20170918Attachment 94A.pdf

2017
Electric Service
Requirements
Revised 01/18/2017
(Blue Book)
This booklet supersedes all previous editions.
Important! See major changes.
This manual with the most current changes will also be available online at:
www.avistautilities.com/assets/eservicemanual.pdf
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MAJOR CHANGES

Available Fault Current and AIC rating requirements. See section 1.22.

Single phase 120/240V services may not exceed 800 amps of continuous load. For services
exceeding 800 amps, a three phase 120/208V or 277/480V service is required. Also all
service meters to be located on outside of building. See Sections 1.8, 3.1 and 4.1.2.

8” x 8” Treated posts are allowed for single phase residential service in lieu of Class 5 poles if
stipulations are met. See Sections 2.2.7 and 2.2.8.

The point of delivery is to be located outside and above ground except in the Spokane
Downtown Network. See Section 1.6.

Avista requires the customer to bring their service entrance including point of attachment up
to the current Avista standards when the service is altered before permanent connection will
be made. See Section 1.10.

Avista will no longer attach to house knobs or chubs on new or altered construction. See
Section 2.2.4.

Avista will terminate in the termination/pull section of switch boards located outside only. See
Section 2.3.1 Switch Board.

480V 200 amp self contained meter cans that are stand alone and not attached to a building
must be mounted on unistrut attached to two 2 inch rigid steel pipes ( with threaded steel
caps) imbedded in concrete. See Sections 2.3.8 and 4.1.6.

Stand alone 400 amp single phase 120/240 self contained meter cans with additional 200
amp breaker boxes mounted alongside the meter can must be mounted on unistrut attached
to two 2 inch rigid steel pipes ( with threaded steel caps) imbedded in concrete. See Sections
2.3.8 and 4.1.6.

400 amp single phase self contained meter cans with a 400 amp main breaker and no
additional breaker boxes alongside can still be mounted on unistrut attached to a full treated
6X6 post imbedded in concrete. See Sections 2.3.8 and 4.1.6.

If you find any errors please Contact the Electric Meter Shop or your Construction Project
Coordinator. See Contact Information later in this book.
Thanks,

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TABLE OF CONTENTS
MAJOR CHANGES ...................................................................................................... I 
PREFACE .................................................................................................................... 6 
SAFETY ....................................................................................................................... 7 
CONTACT INFORMATION .......................................................................................... 9 
1.0 GENERAL SERVICE REQUIREMENTS ............................................................. 10 
1.1 UTILITY RATES & REGULATIONS .................................................................................. 10 
1.2 ELECTRICAL PERMIT & INSPECTION ............................................................................ 10 
1.3 CONNECTION REQUIREMENTS ..................................................................................... 10 
1.4 AVAILABILITY OF SERVICE ............................................................................................. 10 
1.5 SERVICE AGREEMENT ................................................................................................... 10 
1.6 POINT OF DELIVERY ....................................................................................................... 11 
1.7 FLAT RATE ACCOUNTS .................................................................................................. 14 
1.8 AVAILABLE PHASE and VOLTAGE ................................................................................. 14 
1.9 SERVICE ENTRANCE CONDUCTORS ............................................................................ 14 
1.10 SERVICE CHANGES ...................................................................................................... 17 
1.11 LOAD ADDITIONS ........................................................................................................... 17 
1.12 INSTALLATION AND REPAIR ........................................................................................ 17 
1.13 LANDSCAPING ............................................................................................................... 17 
1.14 TREE TRIMMING ............................................................................................................ 17 
1.15 OTHER UTILITIES ........................................................................................................... 18 
1.16 EQUIPMENT PROTECTION ........................................................................................... 18 
1.17 CUSTOMER OWNED EQUIPMENT ON AVISTA POLES .............................................. 18 
1.18 METER SEALS ................................................................................................................ 18 
1.19 MOTORS ......................................................................................................................... 18 
1.20 SERVICE CONDUIT ........................................................................................................ 18 
1.20.1 General Requirements .................................................................................................................. 18 
1.20.2 Conduit Type ................................................................................................................................. 19 
1.20.3 Conduit Trade Size and Number .................................................................................................. 19 
1.20.4 Sweep Size ................................................................................................................................... 20 
1.20.5 Location of Conduit Sweeps at Avista Poles ................................................................................ 21 
1.21 CLEARANCE OF RESIDENTIAL GAS & ELECTRIC METERS ...................................... 22 
1.22 AVAILABLE FAULT CURRENT AT POINT OF DELIVERY ............................................ 23 
1.23 METER ENCLOSURE INSTALLATION IN FLOOD ZONES ........................................... 24 
2.0 RESIDENTIAL SERVICE REQUIREMENTS ....................................................... 26 
2.1 RESIDENTIAL SERVICE CUSTOMER CHECKLIST ........................................................ 26 
2.2 OVERHEAD SERVICE ...................................................................................................... 27 
2.2.1 Point of Delivery .............................................................................................................................. 27 
2.2.2 Service Mast ................................................................................................................................... 27 
2.2.2B Service Mast Cont. ....................................................................................................................... 27 
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2.2.3 Multiple Masts ................................................................................................................................. 28 
2.2.4 Anchor Point ................................................................................................................................... 28 
2.2.5 Service Clearances ......................................................................................................................... 29 
2.2.6 Overhead House Mast .................................................................................................................... 29 
2.2.7 Overhead to Overhead Service Pole .............................................................................................. 31 
2.2.8 Overhead to Underground Service Pole .......................................................................................... 33 
2.2.9 Overhead Service Clearances At Building ..................................................................................... 35 
2.2.10 Clearances to Buildings and Appurtenances ................................................................................ 37 
2.2.11 Overhead Service Clearances Over Ground and Buildings ......................................................... 40 
2.2.12 Clearances Around Swimming Pools and Hot Tubs..................................................................... 42 
2.3 UNDERGROUND SERVICES ........................................................................................... 44 
2.3.1 Point of Delivery .............................................................................................................................. 44 
2.3.2 Service Ditch ................................................................................................................................... 44 
2.3.3 Service Ditch Detail ........................................................................................................................ 45 
2.3.4 Clearance to Transformers ............................................................................................................. 47 
2.3.5 Clearance to Other Equipment Buildings & Swimming Pools ......................................................... 49 
2.3.6 Residential Underground Service ................................................................................................... 51 
2.3.7 Direct Buried Underground Service Pedestal ................................................................................. 54 
2.3.8 Post Type Meter Pedestal .............................................................................................................. 56 
3.0 COMMERCIAL SERVICE REQUIREMENTS ...................................................... 58 
3.1 GENERAL .......................................................................................................................... 58 
3.1.1 Customer Responsibility ................................................................................................................. 58 
3.1.2 Avista Responsibility ....................................................................................................................... 58 
3.2 OVERHEAD SERVICES .................................................................................................... 58 
3.2.1 Point of Delivery .............................................................................................................................. 58 
3.2.2 Mast Location .................................................................................................................................. 59 
3.2.3 Anchor Points .................................................................................................................................. 59 
3.2.4 Current Transformers ..................................................................................................................... 59 
3.2.5 Multiple Masts ................................................................................................................................. 59 
3.2.6 Transformer Mounted Metering ...................................................................................................... 59 
3.3 UNDERGROUND SERVICES ........................................................................................... 59 
3.3.1 Point of Delivery .............................................................................................................................. 59 
3.3.2 Single Phase ................................................................................................................................... 59 
3.3.3 Three Phase ................................................................................................................................... 59 
3.3.4 Transformer Delivery Point ............................................................................................................. 60 
3.3.5 Delivery Point at Secondary Enclosure .......................................................................................... 60 
3.3.6 Building Delivery Point .................................................................................................................... 60 
3.3.7 Vehicle Barriers ............................................................................................................................... 61 
3.3.8 Handholes ....................................................................................................................................... 65 
3.4 PADMOUNTED EQUIPMENT DRAWINGS ...................................................................... 66 
3.4.1 Three-Phase Transformer Concrete Pads ..................................................................................... 66 
3.4.2 Pedestal Mounted Meter Enclosure – For Dedicated Transformer ................................................ 68 
3.4.3 Secondary Enclosures .................................................................................................................... 69 
3.4.4 Padmounted Secondary Enclosure ................................................................................................. 72 
3.4.5 Conduit Entrance 3-Phase Padmounted Junction Enclosures ....................................................... 77 
4.0 METERING REQUIREMENTS ............................................................................. 78 
4.1 GENERAL .......................................................................................................................... 78 
4.1.1 Listing .............................................................................................................................................. 78 
4.1.2 Location .......................................................................................................................................... 78 
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4.1.3 Meter Room Requirements ............................................................................................................. 78 
4.1.4 Meter Identification ......................................................................................................................... 79 
4.1.5 Security ........................................................................................................................................... 79 
4.1.6 Meter Mounting ............................................................................................................................... 79 
4.1.7 Lifting Handles ................................................................................................................................ 80 
4.1.8 Sprinkler Service ............................................................................................................................. 80 
4.2 SELF CONTAINED METERING ........................................................................................ 80 
4.2.1 Manual Circuit Closing (MCC) Sockets .......................................................................................... 80 
4.3 METERING EQUIPMENT RATINGS AND TYPE .............................................................. 81 
4.3.1 Approved Self-Contained Sockets .................................................................................................. 81 
4.3.2 Self-Contained In-Line Socket Diagrams ....................................................................................... 83 
4.4 INSTRUMENT TRANSFORMER METERING ................................................................... 84 
4.4.1 Current Transformer Location ......................................................................................................... 84 
4.4.2 Metering Conduit Requirements ..................................................................................................... 84 
4.4.3 CT Enclosures - General Requirements ......................................................................................... 84 
4.4.4 Multi-Meter: Combination CT & Self-contained .............................................................................. 84 
4.4.5 Pulling/Termination Enclosure Utility Space ................................................................................... 85 
4.4.6 Notes ............................................................................................................................................... 86 
4.4.7 Switchboard Metering ..................................................................................................................... 87 
4.4.8 Single Phase Current Transformer Metering .................................................................................. 88 
4.4.9 Three Phase Current Transformer Metering .................................................................................. 89 
4.5 CELL TOWER METERING ............................................................................................... 90 
5.0 SERVICE VOLTAGES ........................................................................................ 91 
6.0 CUSTOMER GENERATION REQUIREMENTS .................................................. 93 
6.1 Generation Interconnection ................................................................................................ 93 
6.2 Emergency / Standby Generation ...................................................................................... 95 
7.0 TEMPORARY OR CONSTRUCTION SERVICE .................................................. 97 
7.1 Temporary Overhead Service ............................................................................................ 98 
7.2 Temporary Underground Service ....................................................................................... 99 
8.0 SPOKANE NETWORK UNDERGROUND SERVICE POLICY .......................... 100 
8.1. Point of Delivery ............................................................................................................. 100 
8.2. Service Voltages ............................................................................................................. 101 
8.3 Enclosures and Conduit Runs ........................................................................................ 101 
8.4 Easements ...................................................................................................................... 102 
8.5 Metering .......................................................................................................................... 102 
8.6 Generation ...................................................................................................................... 102 
8.7 Other Items ..................................................................................................................... 102 
9.0 ELECTRICAL FORMULAS & COMMON TERMS ..................................................... 103 
APPENDIX A – LIST OF FIGURES............................................................................... 105 
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APPENDIX B – LIST OF TABLES ................................................................................ 107 
INDEX ...................................................................................................................... 108 

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PREFACE
If you are planning to install, repair, or upgrade your electric service, you probably have some
questions and concerns. Avista has designed this handbook to help guide you through the process.
This handbook includes Avista’s requirements. They must be met before a new or modified electric
service can be connected. Although we have tried to include everything, please call your nearest
Avista Utilities office for further details or questions. Spending some extra time during your project’s
planning phase can save time and minimize confusion as it moves ahead.
This handbook supersedes all previous editions. It is published yearly, but since requirements are
subject to change without notice please coordinate your work with Avista.
For the purposes of this book, residential services are those that serve individual residences,
apartments, mobile homes or living units for domestic purposes. Commercial services include all
other services.
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SAFETY

CALL BEFORE YOU DIG

CALL 2 DAYS BEFORE YOU DIG

NATIONAL # 811

LOCAL AREA NUMBERS
SPOKANE _________________________________ 1-800-424-5555
PULLMAN-MOSCOW ________________________ 1-800-424-5555
LEWISTON ________________________________ 1-800-324-1585
CLARKSTON _______________________________ 1-800-553-4344

COEUR D’ALENE AREAS:
BENEWAH – SHOSHONE CO _________________ 1-800-398-3285
BONNER – BOUNDARY CO ___________________ 1-800-626-4950
KOOTENAI CO _____________________________ 1-800-428-4950

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CONTACT INFORMATION

Avista Utilities Call Center

1-800-227-9187
Clarkston / Lewiston / Orofino [phone]
Coeur d’Alene [phone]
Colville 1-800-227-9187
Davenport [phone]
Deer Park 1-800-227-9187
Electric Meter Department 1-800-227-9187
Grangeville [phone]
Kellogg [phone]
Othello 1-800-227-9187
Pullman / Moscow [phone]
Sandpoint 1-800-227-9187
Spokane [phone]
St. Maries [phone]

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1.0 GENERAL SERVICE REQUIREMENTS
These guidelines are based on the typical utility practices necessary to supply reliable and safe service. All
meter and service equipment required for the construction of new or remodeled installations as well as
services disconnected for a period of one year or more and all seasonal installations must meet these
guidelines. In addition installations must conform to the rules and regulations of the inspection authorities
having jurisdiction. These regulations include, but are not limited to the National Electrical Code, National
Electrical Safety Code, State Rules and Regulations, City and County ordinances and codes, and rules on
file with or issued by the Public Utility Commission.
1.1 UTILITY RATES & REGULATIONS
Copies of Avista's currently effective rates, rules, and regulations filed with the Public Utility Commission are
available to you on request or at www.avistautilities.com.
1.2 ELECTRICAL PERMIT & INSPECTION
The customer or their electrician is responsible for obtaining an electrical permit before work is started and
having their completed work inspected by the authority having jurisdiction. The authority having jurisdiction
may be a federal, state, local, or other regional department or individual such as a fire chief; fire marshal;
chief of a fire prevention bureau, labor department, or health department; building official; electrical
inspector; or others having statutory authority. Federal buildings must have electrical inspection by third
party.
1.3 CONNECTION REQUIREMENTS
Avista will connect a new service meeting our requirements that has an inspection sticker posted on site.
When Avista disconnects a service to allow an electrical upgrade or altered service it will be reconnected if
the modifications meet our current standard requirements and;
1. If work is performed by the property owner – a final inspection approval must be posted on site
2. If work is performed by a licensed electrician - inspection requirements vary by local electrical
inspection office. The electrician should call the local Avista office for current Avista standard
requirements. See Contact Information in a previous section.
3. Inspection of that service and equipment is required before reconnection and service must meet
current Avista standards. In some cases an official inspection by the governing agency may also
be required.
4. If any service has been disconnected for a period of one year or more both an Avista
inspection and a local electrical inspection by the governing agency is required.
5. 48 hour notice must be given to Avista for removal of any meter locking device.
6. Avista will not attach any services and facilities to trees.
7. Replacement of mobile homes at a service constitute a major change and require both an
Avista inspection and a local electrical inspection by the governing agency.
8. Seasonal installations that are shut off for less than a year are subject to an Avista safety
inspection and can be required to bring installation up to current code requirements if deemed
unsafe.
1.4 AVAILABILITY OF SERVICE
It is important that Avista be provided, as soon as possible, with accurate load information and other
requested data before the purchase or installation of equipment and wiring. This will allow Avista to
determine the availability of service, service location and available voltage.
1.5 SERVICE AGREEMENT
For new installations a signed service agreement and payment is needed before Avista’s work can be
scheduled.
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1.6 POINT OF DELIVERY
The point of delivery is the location where Avista’s service conductors and the Customer’s service entrance
conductors are connected. Avista requires a building be served using a single point of delivery, supplied
through a single meter installation, at a single voltage and phase classification unless permitted by
exception.
 Avista owns, installs, and maintains equipment on the source side of the point of delivery as well as
the meter and instrument transformers. The Customer is responsible for the equipment on the load
side.
 Buildings, subdivided into individual tenant spaces, require multiple meters for the individual tenants.1
The service entrance conductors for these meters must be fed from a main disconnect, switch board
or bussed together to provide a single point of delivery.
 Metering equipment is located outside of building as close as practical to the point of delivery, but in
no case more than 25 feet.
 The customer is responsible for providing equipment to Avista specifications needed to provide one
point of connection. See the Residential, Commercial Sections or Spokane Network Service section
for acceptable point of delivery equipment.
 The point of delivery is to be located outside and above ground except in the Spokane Downtown
Network. Avista will no longer pull underground secondary conductors through an outside wall or
through a slab into a customer’s building or structure. The point of delivery will be on the outside wall
in a customer provided Pulling/termination enclosure or free standing pulling enclosure mounted on
(2) 2 inch rigid steel pipe (in concrete) with unistrut as needed and must be within 25 feet of metering
equipment. An underground service over 1200 amps will require outside mounted switch gear if
multiple meters are needed and the transformer is not dedicated to one service.
Note: Contact with the appropriate Avista representative during the early planning and design
phase of a project is recommended to help alleviate costly and time consuming modifications
(made by the customer) and required by the utility to meet these requirements.

Exceptions Allowing Multiple Services:
Exceptions require prior written approval by Avista and if required, approval by the authority having
jurisdiction: Additional services may be subject to Exceptional Costs.
 Buildings with multiple privately owned townhouses or zero lot line construction must be provided
with an individual point of delivery for each premise.
 Single buildings that are sufficiently large to make two or more services necessary.
For example it may be impractical to serve an industrial plant with a single service that has
sufficient capacity for any and all future loads. It may also be impractical to design long feeders with
acceptable voltage drops. Voltage drop calculation per National Electrical Code shall be provided
by the customer to confirm this problem.
 Large commercial multi-story buildings require a single point of delivery. Metering for individual
premises may be provided with a minimum number of meter rooms located on various floors if it is
impractical to design long feeders with acceptable voltage drop. Voltage drop calculation per
National Electrical Code shall be provided by the customer.
 Buildings designed for multiple services to supply enhanced reliability.

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 At the request of a Customer, multiple buildings or structures in close proximity used in a single
integrated commercial, industrial, or institutional enterprise can be considered a single premise and
served from a single point. In this case the Customer shall own and be responsible for installation,
operation and maintenance of the electrical distribution system between buildings. Under some
circumstances Avista may provide, own and maintain this system under an agreement.
 Existing single space buildings sub-divided into two or more separate buildings having two or more
separate addresses due to installations of approved fire-walls and parapets shall still be considered
as a single building to be served through single point metering unless such walls are load bearing. In
the event that separation is due to a load bearing wall, Avista will recognize the previous single space
building as two or more completely separate buildings and allow a single point of service to each
buildings.
 Buildings accommodating multiple services that have walls moved such as strip malls, the electrical
services must be altered to match new space and preapproved by Avista representative.
Location
Contact an Avista Construction Representative to determine the location of the point of delivery and
meter before installing any equipment. Avista provides service locations based on capacity requirements,
service quality, safety, access, and cost. All of the following will be considered when determining the location
for the point of delivery.
 Point of delivery at a location with line of site to Avista’s facilities.
 For accessibility it should be installed outside in an unlocked area. Enclosed patios, porches,
carports, and fenced areas which prevent access must be avoided. Fenced areas accessible by
Avista must be preapproved by Avista representative.
 Provide required clearances from and over present and future buildings, garages, driveways,
parking areas etc for overhead service conductors.
 Provide required clearances from buried objects, like septic systems, drain fields and fuel tanks for
underground service conductors.
 Avista will not route underground primary URD cable or service wire under buildings. Any building
built over existing underground primary or secondary conductor will not be energized until overbuilt
conductor is moved at customer expense. Reference: NESC 351 C2.
 Altered Services – normally do not require relocation unless there are serious conflicts with Avista’s
service location requirements. For example serious conflicts would be failure to meet code required
clearances, critical access, or safety concerns.
 Preferred Residential Locations
Failure to install service entrance in a location approved by the utility could result in customer
having to move equipment at their expense
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Figure 1- New Underground or Overhead Electric Service
Transformer or Handhole on the Street Side

Figure 2 - New Underground Service
Transformer in the Backyard
AVISTA FACILITIES
10ft

AVISTA FACILITIES
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Figure 3- New Overhead Service
Transformer in Backyard
1.7 FLAT RATE ACCOUNTS
Avista requires all loads to be metered, but reserves the right to flat rate certain fixed loads under special
circumstances (such as lighting). The terms related to any flat rate situations must be set forth in an
agreement between Avista and the customer. Under no circumstances will Avista flat rate any variable
loads.
1.8 AVAILABLE PHASE and VOLTAGE
The number of phases and service voltage are subject to availability at your location. Contact an Avista
Construction Representative for determination. Special permission is required for more than one service
voltage serving a single building.
On three phase services, all single phase loads must be balanced between the three phases, except for a
four wire delta service.
A list of available service voltages can be found in the Standard Service Voltages section of this booklet.
Single phase 120/240V services cannot exceed 800 amps of continuous load. If load exceeds 800
amps then service must be 3 phase 120/208 or 277/480 volt. All service meters to be located on
outside of building.
1.9 SERVICE ENTRANCE CONDUCTORS
Service entrance conductors must be specified and installed in accordance with the national, state and local
electrical codes. In addition they must meet Avista’s specific requirements.
 The neutral conductor shall be marked with a white strip or tape.
 The customer service entrance conductors will be connected to bottom position in socket.
 On four-wire, 120/240 volt delta installation, an orange marker shall be used to identify that phase
which is approximately 208 volts to ground (high leg or power leg). This shall be located on the right
side of the meter socket, CT landing platform and in the middle of the main disconnect.

 Metered and non-metered circuits shall not be run in the same raceway or conduit.

VISTA TRANSFORMER
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SCOPE:
This standard documents the long standing practice of only marking secondary cable at the service point
with tape that marks phase rotation and not phase designation.

Figure 4 - Cable Phase Rotation Marking

AVISTA Utilities Distribution Standards DU-7.120 ESR Page 1 of 2
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NOTES:
N1. Always verify voltage and rotation before working on any existing 3 phase service regardless of existing
markings.
N2. Avista’s standard practice is to use red, white and blue tape only for marking phase rotation on the utility
side of the service point. No other color tape will be used to mark rotation on the utility side of the service
point.
N3. On a 4 wire 120/240 service, always mark the high leg or (power leg) blue. The other two hot legs shall
be marked red and white.
N4. The NEC code for marking the high leg or (power leg) on a 4 wire 120/240 meter socket or weatherhead
is orange. Always connect the blue marked conductor to the orange marked lug or conductor for this
voltage. On 3 phase services and secondaries, red, white and blue tape is used for marking phase
rotation only, and does not indicate any specific voltage.
N5. Avista will supply ABC or CBA rotation to the weatherhead or meter socket. On new installations, it is up
to the electrician to establish the desired rotation.
N6. Red, white and blue tape can also be used for marking both ends of service conductors during
installation on multiple run services.
N7. Red, white and blue tape matches the red, white and blue leads on Avista standard purchased rotation
meters.
N8. The NEC code for marking the neutral is white. Avista does not mark the neutral. On multiplex
underground cables, the neutral conductor is marked with a yellow stripe. The NESC code does not
specify any color coding for phase rotation or voltage.
N9. While performing maintenance on an existing 3 phase overhead or underground service, the
established rotation must be maintained.
N10. During a scheduled or unscheduled outage, customer electrician may need to be on site to reestablish
the correct phase rotation.
N11. All secondary and service cables shall be marked on both ends using Avista standard cable marking tags
(575-0830). Refer to DU-4.320 for instructions on punching out the necessary information for a specific
run of cable.

REFERENCES:
R1. Refer to DU-4.320 Cable Marking CMT.
R2. Refer to Avista Electric Service Requirements Book latest edition.

AVISTA Utilities Distribution Standards DU-7.120/ESR Page 2 of 2
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1.10 SERVICE CHANGES
Whenever major changes, relocations, or additions are made to the electrical service, metering must be
modified to meet current Avista standards.
Avista will consider a service to be altered when one of the following occurs and will require the customer to
bring their service entrance including point of attachment up to the current Avista standards before
permanent connections will be made.
a) Customer mast of conductors in mast are changed/moved/ or upgraded.
b) Location of the service entrance is moved.
c) The meter can is changed/repaired/ or upgraded.

In the event of Avista replacing an existing Delta 480V 3-wire 3 phase service with a 277/480V Wye 4-wire 3
phase service, Avista will notify customer in writing that the existing 3-wire three phase service has been
replaced with a 3 phase 277/480V 4-wire service. Available fault currents will change significantly at
the service if the neutral is connected at the service (see Section 1.22 for Available Fault Current).
The neutral will be available from Avista for connection at the service panel.
1.11 LOAD ADDITIONS
It is the customer’s responsibility to notify Avista when adding significant load. Before installing electric
tankless water heating systems, central air conditioners, electric vehicle chargers, central electric space
heating, large motors and/or other major loads please contact Avista. Avista representatives will help to
determine it the transformer and service wires are adequate for the increased load. In some cases Avista
will need to install larger transformers and wires to accommodate the increased load. The costs of these
changes may be charged to the customer.
1.12 INSTALLATION AND REPAIR
The customer provides, maintains, and operates at their expense all wiring and equipment, except the
meter, on the load side of the point of delivery.
The customer owns the meter socket and is responsible to remove or remount it to facilitate the installation
of siding. Siding shall be installed so as not to interfere with the installation or removal of the meter.
Avista provides, maintains, and operates at their expense all wiring, poles and equipment, on the source
side of the point of delivery. In addition Avista is responsible for the installation, repair, and calibration of the
electric meter.
Note: On new construction and customer requested changes/alterations to the existing system, the
customer will be responsible for the costs of material and labor required by the utility to meet the
customer’s request. Contact local Avista representative for details on requirements and costs.
1.13 LANDSCAPING
Avista provides information on acceptable methods for screening of pad-mounted transformers and
switching enclosures. These designs should be tailored to fit specific needs of the home or business owner.
This information is available from your local Construction Office or at:
http://www.avistautilities.com/services/electricity/pages/default.aspx

1.14 TREE TRIMMING
The customer is responsible to keep trees and bushes away from overhead service conductors from the pole
to the building. Avista will disconnect the service to make trimming safe. Call Avista 2 working days in
advance of the work. Service disconnects done on weekends and after normal Avista business hours will
require a charge to the customer.
A minimum of 1' of clearance is required from insulated triplex and 3' for open three-wire services.
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1.15 OTHER UTILITIES
It is the customer’s responsibility to coordinate the use of a joint ditch or poles before the permanent service
is connected. Required clearances between utilities must be met.
1.16 EQUIPMENT PROTECTION
It is the responsibility of the customer to provide power conditioning devices that may be required to provide
the quality of “power” necessary for optimum performance of their sensitive equipment such as computers or
other electronic appliances. Since power disturbances can be created on the utility or customer side of the
delivery point, the best locations of these devices may be at the equipment.
Residential customers using computers or critical non-interruptible equipment are encouraged to upgrade
their meter sockets to provide manual circuit closing to prevent accidental outages during meter
maintenance.
Customers are responsible to provide protection for their equipment that could be damaged by single
phasing of three-phase loads.
Customers are responsible for ice protection.
1.17 CUSTOMER OWNED EQUIPMENT ON AVISTA POLES
Customer owned metering, switches, luminaries, signs or other equipment shall not be mounted on Avista's
poles.
1.18 METER SEALS
The purpose of meter seals is for safety and prevention of tampering. Under normal circumstances, only
Avista personnel shall remove seals. It is the customer’s responsibility to notify Avista prior to the
removal of meter seals for any reason. Seals may be removed only in an emergency. Avista must be
notified as soon as possible thereafter. Red seals must not be cut.
Caution: With some types of meter bases, removal of the meter does not de-energize the service.
Any person, who cuts Avista seals and/or wrongfully obtains electric service by by-passing, tampering with,
or modifying a meter, may be convicted of a crime and billed for costs associated with investigation.
Bypassing meter sockets by electricians or customers is not allowed for any reason without Avista approval.
All power must be metered.
1.19 MOTORS
Three phase motors 35 horsepower or larger and frequently started 10 horsepower and larger motors may
require reduced-voltage starting equipment. Avista requires reduced-voltage starting in some cases to limit
voltage flicker and the problems it causes. Avista will furnish starting flicker calculations on request. The
allowed starting current will depend on the frequency of starting, and the size of the electrical service.
Customers can install reduced voltage starting equipment to reduce voltage flicker. Three phase motors 25
horsepower or larger require closed delta or wye service.
1.20 SERVICE CONDUIT
The following information is intended for the installation of electrical service conductor. This information does
not apply to roadway crossings or primary conduit systems.
1.20.1 General Requirements
 Conduit is required in all areas that could be covered by asphalt or concrete, or where required by
Avista.
 Run conduit as straight as possible with the exception of the sweeps required by Avista. The conduit
route, distance, sweep angles, size and number of runs must be pre-approved by the Avista Customer
Project Coordinator.
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 Avista must approve conduit installation prior to backfilling. Do not backfill the last 5 feet to the
transformer or handhole until Avista crews have completed the connection. (Note: The conductor will
not be energized until the backfill has been completed.)
 The customer is responsible to obtain all necessary permits.
 Conduits that are run to the base of a pole must terminate with a sweep at the exact location on the
pole designated by Avista.
 Multiple runs must be bundled together. Conduit sweeps entering handholes or transformers must also
be bundled together. Service conduits enter the left hand side of a single phase transformer as viewed
from the front.
 Pull strings are required on all conduit runs and should be approximately 1/8 inch in diameter and must
be adequate to pull a 1/2 inch rope the entire distance of the conduit run when required.
 The ends of the conduit must be taped or capped, and sealed to keep dirt and water out of the conduit.
Customer is responsible for any obstructions within the conduit.
1.20.2 Conduit Type
 All conduits shall be gray electrical PVC.
 Conduit thickness shall be rated at Schedule 80 above ground or Schedule 40 buried.
 Riser conduits shall be plumb.
 All conduit connections must be glued and fully seated.
 Swedge couplings required on all 2”, 3”, and 4” pipe.
 Factory bell ends are allowed for connections in lieu of swedge couplings.
NOTE* Telescoping coupling (Slip Coupling) inserted in the riser conduit just before the meter in residential
applications is strongly advised as a measure to allow for the settling of the ground and to prevent damage
to the customer’s meter base. Check with your local Avista representative to see if these couplings are
required in your area.
1.20.3 Conduit Trade Size and Number
 For conduit runs with up to three sweeps (270 degrees or less), including the source and the
termination sweeps, and up to 200 feet in length, the diameter of the conduit shall be as specified
below. For other designs contact Avista.
 For commercial systems consider future upgrades in service size that might require larger size or
additional conduit runs.
 Heated bends are allowed up to 30 degrees. The conduit diameter and consistency of the radius must
be maintained.

Service Entrance
Ampacity (Amps)
Residential
(Single Phase)
Commercial
(Single or Three Phase)
200 or less 1 @ 2” 1 @ 3”
201-400 1 @ 3” 1 @ 3”
401-600 1 @ 4” 1 @ 4”
601 & Up Contact Avista Contact Avista
Staff_PR_094 Attachment A Page 20 of 110

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1.20.4 Sweep Size
Conduit Size Minimum Sweep
Radius
2” 24”
3” 30”
4” 36”

                                            Figure 5 ‐ Electric Conduit Sweep Specifications 
 Any conduit sweep that extends above the ground line must be schedule 80 PVC.

2, 3, and 4” Swedge couplings are available at CED 3717 E Main Spokane [phone] and Graybar
4001 E Ferry Spokane [phone]

Staff_PR_094 Attachment A Page 21 of 110

2017 Electric Service Requirements 01/18/2017 Page 21

1.20.5 Location of Conduit Sweeps at Avista Poles

                                        Figure 6- Location of Sweeps on Avista Poles
NOTES:
N1. Risers are not allowed on Avista Utilities air switch poles.
N2. No later than two business days prior to any excavation deeper than 12 inches, the excavator is
required by law to mark the area of excavation and contact the local “One Call” office.
N3. Minimize the disturbance of soil, at the pole, to prevent loss of treated soil and premature deterioration
of the butt of the pole.
N4. All excavations for handholes, manholes and vaults must be no closer, to the pole, than five feet or the
depth of the excavation (A = B), whichever is greater.
N5. Backfill must be tamped or otherwise compacted to prevent settling and must be protected from
erosion.
N6. The joint user is responsible for the cost of installing risers, conduits, ditches and manholes which it
uses for its communications cables. Risers which connect to communication handholes, manholes or
vaults will be owned and maintained by the communication company. Risers which connect to Avista
Utilities handholes, manholes, or vaults will be owned and maintained by Avista Utilities.
N7. Equipment such as power supplies must be mounted under the electric crossarm and must not block
space for additional communication attachments or climbing space. Large boxes should be installed
below the communications space and approved by the Avista Utilities Joint Use Administrator prior to
installation (R2).
REFERENCES:
R1. Refer to DO-1.431 for Joint Use on Air Switch Poles.
R2. Refer to DO-1.443 for Joint Use Power Connections.
R3. Refer to DO-1.449/DU-1.458/ESR for Joint Use New Riser Installations.
AVISTA Utilities Distribution Standards DU-1.460 ESR Page 1 of 1
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2017 Electric Service Requirements 01/18/2017 Page 22

1.21 CLEARANCE OF RESIDENTIAL GAS & ELECTRIC METERS

                                   Figure 7- Residential Gas and electric Meter Clearances
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1.22 AVAILABLE FAULT CURRENT AT POINT OF DELIVERY
Customer must provide service entrance equipment rated to interrupt the amount of fault current
available. Contact Distribution Engineering for information on available fault current at the service point and
for information for arc flash study. Minimum main circuit breaker fault duty rating shall be 10,000 amperes
for residential and 22,000 amperes minimum for multi-family and all commercial installations. Higher ratings
may be required depending on transformer and service wire size and proximity to service entrance. Please
reference maximum fault currents for frequently used transformers below.
Note* All construction temps require a minimum of 15 ft of #2 AL conductor between transformer and
meter.
SINGLE PHASE TRANSFORMER FAULT CURRENT CALCULATIONS at (240V) WITH CONDUCTOR
(Important) When max. available fault current exceeds 10,000 amps the customer will be required to
provide equipment that has an AIC rating that exceeds the max. available fault current.
Max Fault current
Transformer KVA at transformer Conductor size ,length and fault current in amps
15 5208 under 10,000 amps AIC needed with 4/0AL and smaller
25 8013 under 10,000 amps AIC needed with 4/0AL and smaller
37.5 11161 2AL @15ft =7413 2/0AL @15ft =8771 4/0AL @15ft =9399
50 14881 2AL @15ft =8890 2/0AL @15ft =10915 4/0AL @15ft =11906
75 20833 2AL @15ft =10719 2/0AL @15ft =13809 4/0AL @15ft =15434
100 26042 2AL @15ft =11949 2/0AL @15ft =15920 4/0AL @15ft =18119
167 33135 2AL @15ft =13250 2/0AL @15ft =18317 4/0AL @15ft =21290
NOTE: This table is only for reference to help with residential services and single phase temporary
service installations. If your application is not shown here you need to call Avista Utilities to get the
correct max. fault current for your particular transformer and location.
Note: A permanent label with service equipment AIC rating must be affixed to outside of service equipment for
all multi-family and commercial meter installations.
Table 1- Point of Delivery Available Fault Current
Note: Perform NEC Calculations for all Conductor Sizes.
3-Phase Padmount Transformers
Transformer 
KVA 
Secondary 
Voltage 
Max Fault Current 
(AMPS) 
Transformer 
KVA 
Secondary 
Voltage Max Fault Current (AMPS) 
45 208 8922 300 208 41637 
45 480 3866 300 480 18043 
75 208 14870 500 208 42058 
75 480 6444 500 480 18225 
112.5 208 22306 750 208 39280 
112.5 480 9666 750 480 17021 
150 208 27758 1000 208 52374 
150 480 12028 1000 480 22695 
225 208 41637 1500 480 34043 
225 480 18043 
Staff_PR_094 Attachment A Page 24 of 110

2017 Electric Service Requirements 01/18/2017 Page 24

1.23 METER ENCLOSURE INSTALLATION IN FLOOD ZONES

                                           Figure 8- Flood Zone Meter Enclosure Installation

AVISTA Utilities Distribution Standards DO-7.316/DU-9.134 ESR Page 1 of 2
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NOTES:
N1. When elevation of the meter enclosure is required by the authority having jurisdiction, the permanent
installation of deck/platform and stairs shall be installed and provided by customer prior to energizing the
facility.
N2. Meter and conduit to face downstream when installed near flowing water such as rivers and streams.
N3. Additional meter protection required in areas with possible log flows.
N4. Stairs must be treated wood, no taller than 8” rise per step.
N5. Guard rails needed if deck or platform 12” or higher, above grade.

REFERENCES:
R1. NEC Article 682.2
R2. Overhead services must comply to Avista Overhead Construction standard DO-6.260/ESR.
R3. NESC Article 112.C

AVISTA Utilities Distribution Standards DO-7.316/DU-9.134 ESR Page 2 of 2
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2.0 RESIDENTIAL SERVICE REQUIREMENTS
For the purposes of this book, residential service is defined as an individual residence, apartment, mobile
home or living unit used for domestic purposes.
2.1 RESIDENTIAL SERVICE CUSTOMER CHECKLIST
Avista has provided this checklist for the residential customer to assure that all customer work has been
completed before Avista comes to connect the service.
OVERHEAD SERVICE
□ Avista has agreed with the proposed location of service entrance and meter location. (i.e. meter location
with meter 4’ to 6’ up from the ground (See Service Location).
□ A service agreement with Avista has been signed by customer and returned with payment.
□ An insulated strike knob on the mast or strike plate on the house has been installed 8” below the weather
head and 18” of extra wire has been left hanging out of the weather head for utility connection. Neutral
wire extending from weather head has been taped with white tape for identification.
□ Service entrance has been inspected and passed by the State or City Electrical Inspector.
□ Avista has approved the mast height. If the mast is 24” above the roof, or the distance from the building
to the Avista pole exceeds 100’, or the distance from the meter pole to the Avista pole exceeds 125”,
then a back guy on the mast or meter pole is required.
□ 8”x8” meter pole was approved by Avista for this application before it was installed and meets all
requirements.
□ AIC rating of service equipment has been verified to be adequate to handle the available fault current
from the supply transformer with the reduction due to the conductor size and length added in to the total.
UNDERGROUND SERVICE
□ Avista has approved the proposed location of service entrance and meter location (See Service
Location).
□ A service agreement with Avista has been signed by customer and returned with payment.
□ A locate request has been called into the National One Call center (#811) at least 2 business days before
digging is scheduled to begin.
□ Location of transformer and ditch route has been approved by Avista prior to digging.
□ Pulling string has been installed into conduit by customer and all conduit joints have been glued and
proper sized sweeps have been installed on conduit ends (page 10 of handbook) and all conduit that
exits the ground is schedule 80, including the sweep.
□ Ditch and conduit have been inspected by Avista for proper depth and placement of conduit including
sand bedding (if needed) BEFORE backfilling ditch.
□ Service entrance has been inspected and passed by State or City Electrical Inspector.
□ AIC rating of service equipment has been verified to be adequate to handle the available fault current from the
supply transformer with the reduction due to the conductor size and length added in to the total.
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2.2 OVERHEAD SERVICE
2.2.1 Point of Delivery
The point of delivery for self contained metering is at the ends of the service entrance conductor extending
from the mast head. An extra 18” of wire must extend beyond weather head for utility connection and neutral
wire must be taped in white tape or marked by factory stripe.
2.2.2 Service Mast
Service on the gable end of the house must have the meter and attachment point on the gable end. Meters
on metal structures or on buildings with metal roofs, are to be placed on the gable end of the structure to
protect them from ice and snow from the roof.
Avista will no longer attach to a customer provided steel “Dead Mast” or “Roof Horse”. Other options will
need to be considered when trying to lift an overhead service wire over a shop or garage. Contact your local
Avista representative “BEFORE” construction.
Services on buildings without metal roofs not on the gable end of the house or building must be mast-
type extending through the roof. Roof masts must be within 4 ft of the roof’s edge. Services under the
eaves of sloping roofs are only allowed by special permission and must meet all requirements for
service and meter protection as well as meet all clearance requirements (services terminating under
the eaves of metal roofs are not allowed anytime).
Masts extending through metal roofs must be protected from sliding snow & ice by back guying,
mast with guy kit, strut or by building a “Roof Cricket (similar to a chimney cricket) above the mast
with the minimum dimensions of 16” high by 24” wide by 28” deep.
2.2.2B Service Mast Cont.
Electric meters that are under the eaves of buildings with metal roofs must have protection from
sliding snow & ice. Metal roof snow brakes or mini roofs attached to the wall above the electric
meter and cantilevered over the electric meter are not adequate protection.
Adequate protection consists of either –(1) A “Roof Cricket” (similar to a chimney cricket with a
minimum dimension of 16” high by 24” wide by 28” deep) built just above the mast. –(2) Extension of
existing roof overhang to 36” by 48” wide over the electric meter. –(3) Small gable roof (not shed
roof) 24” by 24”, 8 inches above the electric meter attached to the wall and being supported at all 4
corners by 4”X4” commercially treated posts sunk into the ground 18” embedded in concrete.
Note: “Roof Cricket” is to be 24” wide to protect the meter below the roof and needs to be lagged
through the roof sheathing and into a roof framing member.

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2017 Electric Service Requirements 01/18/2017 Page 28

Roof Cricket:

                                              Figure 9- Roof Cricket
2.2.3 Multiple Masts
Avista will connect the service entrance conductors from multiple masts together and supply them with single
set of service drop conductors. Group multiple masts together within 24" of one another. Extend service
entrance conductor from each mast to a common point near the service drop attachment. Avista will
normally make the connections between customer and utility conductors unless size and/or number of
conductor prevent this. Check with Avista for approval.
2.2.4 Anchor Point
All service entrances must be located so that the utility service drop can be anchored to the building at only
one point. These anchoring points must meet Avista strength and height requirements. The strength needed
will depend on the service drop conductor size and number. Guying may be required on a roof mast used as
the anchor point. Contact Avista for information.
Overhead service drops will be run and attached to the anchor point by Avista. The anchor point is furnished
and installed by the customer or their electrician.
Service anchor brackets attached to service masts are preferred. Avista will not anchor to PVC or EMT
conduit. Avista will no longer attach to house knobs or chubs on new or altered construction. (A
strike plate with 2 or 4 lags is the recommended attachment point when not attaching to the mast).
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2017 Electric Service Requirements 01/18/2017 Page 29

2.2.5 Service Clearances
The anchor point must be located to provide the required clearances over buildings and ground. Clearances
are shown later in this section are for reference only. Call Avista to determine design clearances based on
service conductor size and length.
2.2.6 Overhead House Mast

Figure 10- Overhead House Mast
AVISTA SUPPLIED MATERIAL:
Overhead service conductor from transformer, “H” connectors to connect to customer service wire,
And deadend service clamps to attach to mast.

CUSTOMER SUPPLIED MATERIAL:
Service wire, meter base, mast conduit, and attachment bracket with insulator. The attachment bracket can
be mounted on the mast or building. Screw type attachment brackets (house knob or chub) are inadequate
for modern services. They are no longer allowed for new or altered construction. A strike plate with 2 or 4
lag screws is recommended.

AVISTA Utilities Distribution Standards DO-6.230 ESR Page 1 of 2
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2017 Electric Service Requirements 01/18/2017 Page 30

NOTES:
N1. Avista owned equipment must meet National Electrical Safety Code and Avista Utilities
Standard Practices which may vary from National Electrical code and local requirements in
some cases.
N2. Avista can assist the customer in determining the service location, attachment height and
metering equipment requirements. Call the local office number listed in the Electric Service
Requirements Handbook early in the planning stage.
N3. Contact local inspectors for specific information regarding design of the service entrance.
N4. The service entrance must be inspected by local authorities and approved by
Avista before service conductors can be installed.
N5. Avista prefers no couplings in the mast above the roofline when the mast is being used for the anchor
point for the service conductor.

REFERENCES:
R1. WAC 296-46B-230
R2. NESC 234
R3. Refer to DO-3.330 for clearances to other buildings.
R4. Refer to DO-6.210 for service drop clearances.
R5. Refer to DO-6.270 (ESR Section 2.2.9) for service drop clearances to attached buildings
R6. Refer to DO-6.107 through DO-6.149 for stringing sag and tension of service conductors.

AVISTA Utilities Distribution Standards DO-6.230 ESR Page 2 of 2
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2017 Electric Service Requirements 01/18/2017 Page 31

2.2.7 Overhead to Overhead Service Pole

                        Figure 11- Overhead to Overhead Service Pole

NOTES:
N1. The customer provides and installs all equipment on the load side of Avista’s mast head connections;
pole, ground rod, mast conduit, weather head, meter socket, service panel, entrance wires, service bracket
(service attachment point), and down guy if required.
N2. The customer must construct the service entrance per local code requirements and have it inspected by
local authorities before Avista Utilities conductor can be installed. Permit and inspection sticker must be
displayed.
N3. Contact Avista Customer Project Coordinator for help in determining service attachment height, pole
locations and clearance from cable TV and telephone conductors. Avista must determine the service
attachment point to meet required clearances.
AVISTA Utilities Distribution Standards DO-6.260 ESR Page 1 of 2
Staff_PR_094 Attachment A Page 32 of 110

2017 Electric Service Requirements 01/18/2017 Page 32

NOTES CONT:
N4. The service pole must be a class 5 (N8) or better new commercial butt treated Western Red Cedar or
Full Pressure Treated pole or approved 8” x8” post (N9). Set the pole to a depth of 2ft plus 10% of pole
height or at least 5 ft. The pole must be plum and have truck access.
N5. 5/16” galvanized steel guy cable and approved anchor is required if the service drop is longer than 125
feet and/or if the span crosses other structures, or if required by Avista or the electrical inspector. Two
to 1 slope required.
N6. Extend the service wire tails 18 inches or more from the weather head to allow for Avista’s connections.
The neutral wire shall be marked with a factory white stripe or white tape.
N7. Depending on the meter socket style, line and load side conduit may need reversal.
N8. Class 5 dimensions
Length of Pole (ft) 20 25 30 35 40 45 50
Minimum circumference at 6 ft
from butt (in)
25.0 28.0 30.0 32.0 34.0 36.0 37.5
N9. An 8”X8” square post can be used for a permanent overhead single phase residential
service with the following stipulations:
Post is (non laminated) full length commercially treated and has a length (before being installed into the
ground) of no longer than 25ft and that the access to the post is bucket truck accessible.
Service wire being attached by Avista Utilities is no larger than a #2 triplex (1 run) and the span is 75 ft or
less and it does not pass over a roadway ( Passing over residential driveways is allowed if the driveway is
not subject to large truck traffic: i.e. garbage truck )
An insulated strike plate or thru bolt with insulated clevis is installed 8 inches below the weather head for the
attachment point. A house knob or “Chub” is no longer an approved attachment point.
Post will be installed in a hole with a minimum of 12 inch diameter totally filled with concrete and will be to
the depth of 4 ft for posts up to 20ft and 5 ft depth for poles from 20 ft 6 inch to 25 ft.
Permission to use a post instead of a pole for each application has been PREAPPROVED by the local
Avista office BEFORE it is installed. (The post can and will be rejected by the Avista field representative
if it is determined to be subpar in anyway: i.e. (large multiple knots in one location, deep surface rot,
excessively twisted, large chunks missing or if post begins to pull over under the required tension of
the service wire upon connection or anytime thereafter. )

AVISTA Utilities Distribution Standards DO-6.260 ESR Page 2 of 2
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2017 Electric Service Requirements 01/18/2017 Page 33

2.2.8 Overhead to Underground Service Pole

Figure 12- Overhead to Underground Service Pole
NOTES:
N1. The customer provides and installs all equipment on the load side of Avista’s mast head connections;
pole, ground rod, mast conduit, weather head, meter socket, service panel, entrance wires, service
bracket (service attachment point), and down guy if required.
N2. The customer must construct the service entrance per local code requirements and have it inspected
by local authorities before Avista Utilities conductor can be installed. Permit and inspection sticker
must be displayed.

AVISTA Utilities Distribution Standards DO-6.261 ESR Page 1 of 3
Staff_PR_094 Attachment A Page 34 of 110

2017 Electric Service Requirements 01/18/2017 Page 34

NOTES CONT:
N3. Contact Avista Customer Project Coordinators for help in determining service attachment height, pole
locations and clearance from cable TV and telephone conductors. Avista must determine the service
attachment point to meet required clearances.
N4. The service pole must be a class 5 (N7) or better new commercial butt treated Western Red Cedar or
Full Pressure Treated pole or 8”x8” treated post (N8). Set the pole to a depth of 2ft plus 10% of pole
height or at least 5 ft. The pole must be plum and have truck access.
N5. 5/16” galvanized steel guy cable and approved anchor is required if the service drop is longer than 125
feet and/or if the span crosses other structures, or if required by Avista or the electrical inspector. Two
to 1 slope required.
N6. Extend the service wire tails 18 inches or more from the weather head to allow for Avista’s connections.
The neutral wire shall be marked with a factory white stripe or white tape.
N7. Class 5 dimensions
Length of Pole (ft) 20 25 30 35 40 45 50
Minimum circumference at 6 ft from butt (in) 25.0 28.0 30.0 32.0 34.0 36.0 37.5
Minimum circumference of top of pole 19 inches
N8. An 8”X8” square post can be used for a permanent overhead single phase residential
service with the following stipulations:
1) Post is (non laminated) full length commercially treated and has a length (before being installed into
the ground) of no longer than 25ft and that the access to the post is bucket truck accessible.
2) Service wire being attached by Avista Utilities is no larger than a #2 triplex (1 run) and the span is 75
ft or less and it does not pass over a roadway (Passing over residential driveways is allowed if the
driveway is not subject to large truck traffic: i.e. garbage truck)
3) An insulated strike plate or thru bolt with insulated clevis is installed 8 inches below the weather head
for the attachment point. A house knob or “Chub” is no longer an approved attachment point.
4) Post will be installed in a hole with a minimum of 12 inch diameter totally filled with concrete and will
be to the depth of 4 ft for posts up to 20ft and 5 ft depth for poles from 20 ft 6 inch to 25 ft.
5) Permission to use a post instead of a pole for each application has been PREAPPROVED by the
local Avista office BEFORE it is installed. (The post can and will be rejected by the Avista field
representative if it is determined to be subpar in anyway: i.e. (large multiple knots in one
location, deep surface rot, excessively twisted, large chunks missing or if post begins to pull
over under the required tension of the service wire upon connection or anytime thereafter. )
AVISTA Utilities Distribution Standards DO-6.261 ESR Page 2 of 3

REFERENCES:
R1. Refer to DO-3.302 through DO-3.366 for Clearances.
R2. Refer to DO-1.413 and DO-1.416 for Joint Use Clearances.
R3. Refer to DO-6.210/ESR and ESR Section 2.2.11 for Service Clearances.
R4. Refer to ANSI 05.1 for Pole Classes.

AVISTA Utilities Distribution Standards DO-6.261 ESR Page 3 of 3
Staff_PR_094 Attachment A Page 35 of 110

2017 Electric Service Requirements 01/18/2017 Page 35

2.2.9 Overhead Service Clearances At Building

                       Figure 13- Overhead Service Clearances at Building

AVISTA Utilities Distribution Standards DO-6.270 ESR Page 1 of 2
Staff_PR_094 Attachment A Page 36 of 110

2017 Electric Service Requirements 01/18/2017 Page 36

NOTES:
N1. A roof. balcony, or area is considered readily accessible to pedestrians if it can be casually accessed
through a doorway, ramp, window, stairway, or permanently mounted ladder by a person on foot who
neither exerts extraordinary physical effort nor employs tools or devices to gain entry. A permanently
mounted ladder is not considered a means of access if its bottom rung is 8 ft or more from the ground or
other permanently installed accessible surface.
N2. These clearances to building openings apply to the closest point on the service drop;
conductor, drip loop, or connectors. They do not apply to the meter.
N3. Service attachment height must be such that these minimum building clearances as well as clearances
above ground, driveways and streets can be met. Avista can assist the
customer in determining the service mast height to meet these requirements. Call the local
office number listed in the Electric Service Requirements Handbook early in the planning
stage.
N4. Services cannot be connected if service drop attachment height prevents required
clearances from being met.
N5. Meter sockets that are installed within 15 inches from center of meter to wall of structure (inside corner)
will not be approved or hooked up.

REFERENCES:
R1. NESC 234C3
R2. NEC 230.24
R3. Refer to DO-6.230 (ESR Section 2.2.6) for house mast specifications.
R4. Refer to DO-6.107 through DO-6.149 for stringing sags and tensions of service conductors.
R5. NESC Table 234-1 1(b)(1)

AVISTA Utilities Distribution Standards DO-6.270 ESR Page 2 of 2
Staff_PR_094 Attachment A Page 37 of 110

2017 Electric Service Requirements 01/18/2017 Page 37

2.2.10 Clearances to Buildings and Appurtenances

Figure 14- Clearances to Buildings and Appurtenances
AVISTA Utilities Distribution Standards DO-3.330 ESR Page 1 of 3
Staff_PR_094 Attachment A Page 38 of 110

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                                 Table 2- Clearances to buildings and Appurtenances

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NOTES:
N1. For conductors above surfaces provided the vertical clearances above based on final unloaded sag at
+176 degrees F (R5).
N2. For conductors below projections use the initial unloaded sag at -20 degrees F (R4).
N3. Check with local fire departments for ladder space clearances.
N4. Clearances are code requirements or Avista Utilities Standard Practices. Clearances less than those
listed or higher voltages must be approved by the Avista Utilities Engineering Department.
N5. A roof, balcony, or area is considered readily accessible to pedestrians if it can be casually accessed
through a doorway, ramp, window, stairway, or permanently mounted ladder by a person on foot who
neither exerts extraordinary physical effort nor employs tools or devices to gain entry. A permanently
mounted ladder is not considered a means of access if its bottom rung is 8 ft or more from the ground
or other permanently installed accessible surface.
N6. The transitional areas marked “T” in the above drawings should be treated as horizontal clearance
area.

REFERENCES:
R1. NESC 234.
R2. WAC 296 – 155 – 459(1)(d).
R3. Refer to DO-3.334 for Other Structures.
R4. Refer to Section DO-3.2 for Sag & DO-6.1 for Conductors.
R5. Refer to DO-3.270 for Final Vertical Sag at 176 Degrees F and DO-6.149 for Services and Secondary
Final Vertical Sag 176 Degrees F.
R6. Refer to DO-3.302 for Blowout (In Feet).

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2.2.11 Overhead Service Clearances Over Ground and Buildings

Figure 15- Overhead Service Clearances over Ground and Buildings
DIRECTIONS:
D1. Provide the clearances shown using the final sag listed in DO-6.149.
NOTES:
N1. Clearances are code or Avista Utilities Standard Practices. Clearances less than those
listed or for higher voltages must be approved by the Avista Utilities Engineering
Department.
N2. Trees cannot be used to support service conductor.
N3. A roof, balcony, or area is considered readily accessible to pedestrians if it can be casually
accessed through a doorway, ramp, window, stairway, or permanently mounted ladder by
a person on foot who neither exerts extraordinary physical effort nor employs tools or
devices to gain entry. A permanently mounted ladder is not considered a means of access
if its bottom rung is 8 ft or more from the ground or other permanently installed accessible surface.

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NOTES CONT:
N4. In areas subject to combine harvesting increase clearances to 20 ft when possible.
N5. Altered services will require the customer to change clearances (as needed) to meet Avista’s current
clearance requirements.

REFERENCES:
R1. NESC 232
R2. NESC 234

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2.2.12 Clearances Around Swimming Pools and Hot Tubs

Figure 16- Clearances Around Swimming Pools and Hot Tubs
PHASE TO GROUND VOLTAGE
Grounded
Guys &
Grounded
Neutrals
Multipl
ex 0 -
750V
Bare
Wire 0
- 15kV
Bare
15 -
50kV

Horizontal limit for overhead
clearances from inside wall of
pool
10.0 ft 10.0 ft 10.0 ft 10.0 ft
A
Clearances in any direction
from the edge of pool, water
level or base of the diving
platform
22.0 ft 22.5 ft 25.0 ft 27.0 ft
B Clearance in any direction from
the diving platform or tower 14.0 ft 14.5 ft 17.0 ft 18.0 ft
V Vertical clearance over
adjacent land
See DO-
3.314(R4) -- -- --
                            Table 3- Clearances Around Swimming Pools and Hot Tubs

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NOTES:
N1. Conductors over a pool are not recommended.
N2. Wires and conductors within the distance A of the edge of a swimming pool must meet the clearance
requirements above.
N3. Wading pools must meet the requirements of DO-3.314(R4).
N4. Hot tubs and therapeutic pools (near residence) must meet the requirements of DO-3.330 (R7).
N5. Provide the minimum vertical clearances above based on the final unloaded sag at 176 degrees F as
listed in DO-3.270(R5).
N6. Add the blowout displacement listed in DO-3.302(R6) to meet the horizontal and directional clearances
above.

REFERENCES:
R1. NESC 234E1(Table 234-3), 351C1.
R2. NEC 680-8.
R3. Refer to DU-4.222/ESR for Clearances to Other Equipment, Buildings and Swimming Pools.
R4. Refer to DO-3.314 for Vertical Clearance to Ground & Roadway.
R5. Refer to DO-3.270 for Final Vertical Sag 176 Degrees F.
R6. Refer to DO-3.302 for Blowout.
R7. Refer to DO-3.330 Clearances to Buildings and Appurtenances.
.

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2.3 UNDERGROUND SERVICES
2.3.1 Point of Delivery
Self-Contained Meters
Avista will terminate utility service lateral conductors in the customer supplied meter socket.
Instrument Rated Meters
Avista will terminate utility service lateral conductors on the customer provided current transformer mounting
bracket landing lugs.
Self-Contained Meter Modules
2 – 6 Units:
Avista will terminate utility service conductors on the bus of a 2 to 6 meter modules.
More than 6 Units:
Avista will terminate utility service conductors at the main disconnect feeding several multiple meter
modules.
Switch Board
Avista will terminate in the termination/pull section of switch boards located outside. Termination of Avista
secondary wire in switch boards located in buildings will no longer be allowed. Customer will be required to
furnish outside Switch Board gear when the ampere rating exceeds 1200 amps on non-dedicated
transformer services. An option in this case is for the customer to install, own and maintain service
conductors from the building to Avista transformer. Switch boards shall meet EUSERC requirements with
manufacturing drawings to be preapproved by Avista. See additional information in the Meter
Requirements Section 4.4.7.
2.3.2 Service Ditch
The ditch route, width and the need for sand padding and bedding must be pre-approved by the Avista
Customer Project Coordinator.
All ditching must be inspected and approved by Avista personnel prior to backfilling and crew scheduling.
Conductor will not be energized until the ditch has been fully backfilled. All ditches must be in accordance
with Avista design requirements. Truck access is desirable. Time and material charges may result from
additional trips necessary for energizing or correction of facilities.
Customer is responsible for backfilling and returning landscape back to required condition, haul-off, and all
compaction requirements, including select backfill if required. Customer is also responsible for obtaining all
required permits.
State law requires all excavators to notify “One-Call” 48 hours in advance so that all utilities may locate and
mark buried facilities before trenching begins. The law requires that the ditch be hand-dug within 2 feet of a
locate mark. Extreme caution should be used. All hand-digging must be completed prior to inspection by
Avista.
Ditches may be dug to within 6 inches of a padmount transformer or handhole. Allow more distance if soil
conditions cause ditch to cave in. Extreme caution should be used. The conduit must be installed to the end
of the ditch and the sweep left unattached for Avista crews to complete.
Ditches may be dug to the base of a pole to a point designated by the Avista Customer Project Coordinator.
A 3 foot depth by 2 foot width ditched area must be provided at the bottom of the meter base to allow for
adequate work space. Ditch must be in relation to final grade within 2”- 4”, including all drainage areas.
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2.3.3 Service Ditch Detail

                                                           Figure 17- Service Ditch Detail
NOTES:
N1. Gas service pipe and electric conduit should not be run in the water ditch. Avista requires 5’ separation
between water mains and electric cable. Refer to DU-1.410.
N2. Bedding and padding for services in conduit shall be classified as select backfill. Select
backfill is clean, screened material consisting of 3/4" minus rock and sand free of rubbish,
cinders, chemical refuse or other materials that could cause damage to the conduit.
N3. All customer ditches must pass Avista Utilities inspection.
N4. Approved backfill shall not contain any rock larger than 4 inches.
N5. Electric and communication cables may be installed with less than 12 inches separation
when the general joint use requirements and the requirements of this standard are met. All
parties
with less than 12 inches separation must agree to random lay. Refer to DU-1.420.
N6. All cables must have at least 12 inches radial separation from URD structures such as
natural gas lines, fuel lines, building foundations, other cables not in random lay, etc.
N7. Gas services should be installed with a 5' minimum longitudinal separation from sewer utility
pipelines or storm drains or at further distances as specified by the appropriate regulating
agency.

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REFERENCES:
R1. NESC Section 35.
R2. Refer to DU-1.420 for Joint Use Random Lay.
R3. Refer to Gas Standard Trenching and Backfilling 3.15.
R4. Refer to DU-7.450 for Service Cable Ditch.
R5. Refer to Electric Service and Meter Requirements.

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2.3.4 Clearance to Transformers

Figure 18- Clearance to Transformers
NOTES:
N1. The locations of the pad, transformer, and the point of delivery shall be as specified by
Avista Utilities prior to the start of site preparation and construction.
N2. The transformer shall be located to provide the following clearances. Boom truck access must be
provided.

CLEARANCE TO: SHALL BE NO LESS THAN
A. Noncombustible wall (N6) 2 feet
B. Wall with combustible component (N6, N7) 8 feet
C. Doors, windows, or other openings 8 feet
D. Combustible eaves, decks, or patio roofs 8 feet horizontal from eave,
14 feet or less above grade (N7) deck, or roof
E. Other vertical obstructions Boom truck Access Required
F. Gas Meter 3 feet
G. Propane Tank Refer to DU-4.222

N3. The front of the transformer shall open away from the building. An area clear of all obstructions
including landscaping must be provided for a radius of 10 feet from the front of the transformer,
to provide personnel access for the operation and maintenance of the transformer. In addition, the
grade of the ground at the pad-mounted transformer shall be such that any oil leaking from the
transformer will flow away from the building.
N4. Transformers shall not be covered, concealed, disguised, or enclosed. Where fences are
permitted, they must be at least two (2) feet from the transformer on all sides (or more if required to
allow the doors to open fully), must allow unrestricted access to the front, and must meet the
clearance requirements listed above.

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NOTES continued:
N5. Pedestal and meter cabinets shall not be in front of or obstruct the transformer doors. The minimum
distance from the edge of the three phase transformer pad to the meter is 1 foot (R6, R7).
N6. The local Fire Marshall or Building Code Inspector will determine the classification of the structure.
Normally, the following are classified as noncombustible: concrete, structural masonry with wood or
timber framing, and all-steel where no combustible material can be erected against the interior
surface. Steel siding with wood framing is considered combustible.
N7. Transformers containing only non-combustible fluid (FR-3) and duly labeled may be placed within
four (4) feet of a wall or overhanging eave containing combustible components.
N8. The pad shall be located and sized to permit the required clearances. No part of the transformer
shall extend beyond the outer edge of the pad. (See R7, DU-5.122, for concrete pad dimensions
and construction details).
N9. Phone and TV pedestals must not be in front of the transformer and must be at least 2’ away from
sides and back of transformer.

REFERENCES:

R1. WAC 296-46B-450.
R2. WAC 296-24-95703.
R3. International Building Code Chs. 6, 7
R4. Distribution Engineering FR3 Policy and Cold Weather Documents.
R5. Refer to DU-4.222 for clearances to Propane Tanks and equipment
R6. For metering cabinet and cans, see Electric Service and Metering Requirements Book.
R7. Refer to DU-5.122 Concrete Pads Three-Phase Transformers.
R8. Landscape Screening for Pad-mounted Transformers booklet.

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2.3.5 Clearance to Other Equipment Buildings & Swimming Pools
SCOPE:
This standard provides direction for establishing clearances to existing buildings and other equipment when
installing underground distribution cables and equipment.
                     Figure 19- Clearances to Other Equipment Buildings and Swimming Pools
AVISTA Utilities Distribution Standards DU-4.222 ESR Page 1 of 3

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Propane Tank Capacity
(gallons of water)
Minimum Distance
to Buried Tank (ft)
Minimum Distance to Above-
Ground Tank (ft)
< 501 10 10
501 - 2000 10 25
2001 – 30,000 50 50
30,001 or more 50 Contact Distribution
Engineering

Table 4- Required Distance between Underground Distribution Equipment and Propane Facilities
NOTES:
N1. Transformers and secondary pedestals shall have a minimum of 4' clearance from fire hydrants to
facilitate water maintenance and fire department operations. Secondary handholes may be substituted
where 4' minimum clearance is not attainable.
N2. Clearance to fuel tank shown is ONLY applicable for tanks containing fuel oil. Required clearances to
Propane tanks are defined in Table 1; propane tank capacity MUST be confirmed before construction
begins.
N3. If any Propane handling facility other than a tank is involved, or if the electrical distribution equipment is
downhill from the propane equipment, contact Distribution Engineering.
N4. Electric Distribution Equipment located within 15 feet of a propane tank shall be approved for National
Electric Code Class I, Group D, Division 2 application.
N5. Cables may not be installed under above-ground pools.
N6 Refer to Joint Use section for clearances to other underground utilities. (R8)
N7. Maintain 5' minimum distance between water main and electric.
N8. Use polycrete handholes for installation in driveways or areas where vehicles may drive over.
N9. Avista Utilities will not install underground primary or service wire under any portion of a building. (R1,
R4)
N10. Above-ground transformers or junction enclosures must be located at least five feet back from curb,
road edge, or other traffic area unless bollards or other protective devices are installed between the
curb or road edge and the transformer.

REFERENCES:
R1. NESC 351C1 & 351C2
R2. NEC 500.5(2); 500.6(4)
R3. Liquefied Petroleum Gas Guide NFPA 58, 2004; Sections 6.3, 6.20.2
R4. Refer to Avista Utilities Electric Service Requirements book.
R5. Refer to DU-5.020 for Transformer Clearances
R6. Refer to DU-7.325 for Traffic Rated Handhole
R7. Refer to DO-3.338 for Swimming Pools
R8. Refer to Section DU-1.4 for Joint Use

AVISTA Utilities Distribution Standards DU-4.222 ESR Page 2 & 3 of 3
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2.3.6 Residential Underground Service

                                      Figure 20- Residential Underground Exterior Service

These are general Avista Utilities requirements. The customer or their electrician must consult the local
electrical code authority for specific requirements. An electrical inspection permit decal must be
displayed before a service connection can be made.

AVISTA Utilities Distribution Standards DU-9.130 ESR Page 1 of 3

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Figure 21- Residential Underground Exterior Service 2

AVISTA Utilities Distribution Standards DU-9.130 ESR Page 2 of 3

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NOTES:

N1. The company will pull service conductor into flush or recessed mounted 200 or
400 amp meter sockets. The socket must be rated for underground services.
N2. Use only the off-center knockouts in the bottom of the meter socket. Applies to 200 and 400 amp cans.
N3. Avista to seal the source side conduit in recessed mounted meter bases. Use Fire Barrier Water Tight
Sealant stock number 668-0600 with Fire Barrier Packing
Material stock number 668-0601 if needed.
N4. Tamping required to prevent the conduit from pulling out of meter base.
N5. Meter must be mounted on gable end of home or shop/garage having a metal roof or must
have the same protection spelled out in Section 2.2.2B of the Electric Service Requirement
Handbook.
N6. Customer to provide expansion coupling as needed and when required by local office. EXPANSION
COUPLINGS CANNOT BE USED IF CONDUCTORS CONNECT TO BOTTOM OF METER BASE.
N7. Install adequate slack in service conductors to compensate for possible settling or shifting.

REFERENCES:

R1. See DU-7.450 for ditching requirements.

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2.3.7 Direct Buried Underground Service Pedestal

Figure 22- Direct Buried Underground Service Pedestal

These are general Avista Utilities requirements. The customer or their electrician must consult the local
electrical code authority for specific requirements. An electrical inspection permit decal must be
displayed before a service connection can be made.
The customer furnishes and installs the following:
Direct Buried metal or UV stabilized fiberglass or plastic meter base & pedestal
Utility service trench, backfill, and conduit as required by Avista
Ground rod(s), connectors and bonding wire
Conduit and wire as necessary to serve the home
Conduit sweep or continuous conduit as required

Avista Utilities furnishes and installs the following:
Meter
Utility service wire

AVISTA Utilities Distribution Standards DU-9.131 ESR Page 1 of 2

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Meter Pedestal Requirements
200 amp meter base
Corrosion protection on the buried section of metal pedestals
Meter sealing ring
Ventilation
The utility service cable pull and terminating section shall be lockable, and restricted to Avista use only. This
area must be kept clear for maintenance access.
Unmetered wire between Avista connections and top side of meter base must remain accessible only to
Avista.
Corrosion inhibitor on aluminum connections
Plumb installation with the meter facing away if located within 5 feet of the structure.
Pedestal must not be located under drip eave of building or where sliding snow can impact pedestal.

REFERENCES:
R1. See DU-7.450 for ditching requirements.

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2.3.8 Post Type Meter Pedestal

Figure 23- Post Type Meter Pedestal

NOTES:
N1. These are general Avista Utilities requirements. The customer or their electrician must consult the local
electrical code authority for specific requirements. An electrical inspection permit decal must be
displayed before a service connection can be made.
N2. Customer to furnish and install pole or post.
N3. Customer to furnish and install Meter / disconnect enclosure and sealing ring.
N4. Customer to furnish and install Utility service trench, backfill, and conduit as required by Avista.
N5. Customer to furnish and install ground rod(s), connectors and bonding wire.
N6. Customer to furnish and install conduit and wire as necessary to serve the home.
N7. Avista Utilities to furnish and install meter and utility service wire.
N8. Pedestal must not be located under drip eave of building or where sliding snow could impact pedestal.
N9. Meter pedestal must be at a 6” x 6” new commercially treated post or attached to a minimum 8” top
diameter new commercially butt treated cedar or full treated white wood pole.

AVISTA Utilities Distribution Standards DU-9.132 ESR Page 1 of 2
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NOTES CONT:

N10. Meter pedestal must be installed so the utility service cable pull and terminating section shall be
lockable, and restricted to Avista use only.

N11. Meter pedestal must have corrosion inhibitor on aluminum connections.

N12. Meter pedestal must be kept clear for maintenance access.

N13. Meter pedestal must have plumb installation with the meter facing away if located within 5 feet of the
structure.

REFERENCES:

R1. Refer to DU-7.450 for Joint Use Service Ditch Detail.

AVISTA Utilities Distribution Standards DU-9.132 ESR Page 2 of 2
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3.0 COMMERCIAL SERVICE REQUIREMENTS
3.1 GENERAL
For the purposes of this book, a commercial premise is used for other than domestic living.
A single point of delivery will be provided to a commercial building. Metering will be located as close as
practical to this point. See Point of Delivery and Service Location sections in General section for additional
information.
Commercial service design requirements vary widely depending on customer needs, site requirements and
electrical design constraints. To determine transformer and service conductor requirements contact Avista
Construction Project Coordinators during architectural design phase and before construction of commercial
site to answer your questions and ours when planning begins. Please provide a copy of the physical and
electrical site plans to the CPC before construction begins. Spending some extra time up front can save time
and minimize confusion as the project moves ahead.
Inside commercial grow operations cannot exceed 800 amps of true load for single phase service.
For loads larger than 800 amps, a 120/208V or 277/480V 3 phase service is required. All service
meters must be located on outside of building.
3.1.1 Customer Responsibility
The customer will supply and install:
 Service entrance mast(s), and anchor points and guying or bracing if needed.
 A single point of connection for Avista service drop or lateral conductors.
 Meter socket for self-contained meter or
 CT enclosure w/CT mounting base and meter socket or enclosure.
 See Metering Requirements for specific information on the metering equipment needed for
various services.
 Additional specific requirements are listed below.
3.1.2 Avista Responsibility
Avista will supply and Install:
 Transformer(s)
 Service conductors to point of delivery
 Current Transformers and instrument wiring if required
 Meter(s)
 Avista will make all electrical connections at agreed upon point of delivery (line side for termination
enclosures and both line/load sides for pad transformers and secondary enclosures).
3.2 OVERHEAD SERVICES
3.2.1 Point of Delivery
The point of delivery for self contained metering is at the ends of the service entrance conductor
extending from the mast head. An extra 18” of wire must extend beyond weather head for utility
connection and neutral wire must be taped in white tape or marked by factory stripe.
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3.2.2 Mast Location
Contact Avista’s Design Representative to determine where on the building to locate the mast. Wall or roof
mounted masts may be used. Roof masts must be within 4 ft of the roof’s edge. Masts on building walls
must be mounted or guarded so that snow and ice damage to the service and metering equipment is
prevented.
3.2.3 Anchor Points
Anchoring points are required to meet Avista strength and height requirements. Commercial services must
meet the clearance requirements in the Overhead Residential Section. The strength needed will depend on
the service drop conductor size and number. Guying may be required on the roof mast used as the anchor
point. Refer to Section 2.2.6 for information.
3.2.4 Current Transformers
Current transformers for building points of delivery will be installed in a wall mounted meter enclosure. See
Meter Requirements Section 4.0 for details. Current transformers will be mounted at the transformer bank
in certain applications. See below.
3.2.5 Multiple Masts
The customer may use multiple masts to feed various distribution panels or to feed multiple meters. Multiple
masts must be grouped together so there is a single point of delivery for Avista’s service drop conductors.
Extend service entrance conductor from each mast to a common point near the service drop attachment.
Avista will normally make the connections between customer and utility conductors unless size, number of
conductors or improperly spaced masts prevent this. Check with Avista for approval.
3.2.6 Transformer Mounted Metering
Avista requires three phase overhead transformer banks larger than 300kVa to be rack mounted using two
poles. Transformer or rack mounted metering is preferred when a single meter is supplied using rack
mounted transformers.

3.3 UNDERGROUND SERVICES
3.3.1 Point of Delivery
The point of delivery for underground services will vary depending on the circumstances described below.
Contact Avista’s Customer Project Coordinator to determine the location in your case.
3.3.2 Single Phase
The point of delivery for single phase underground service is normally at the building. Avista conductors are
run to this point and connected to the landing lugs in a self-contained meter socket, CT mounting base or
pulling/termination enclosure.
3.3.3 Three Phase
The point of delivery and meter for a service from a dedicated transformer will be at the transformer. A
secondary termination enclosure will be required if the number of customer secondary conductors exceeds
maximum conductors allowed in the transformer. See the table in Section 3.4.4 for the maximum number
of conductors.
For multiple meters on a single building the preferred point of service is the outside of the building. Avista
will no longer pull secondary conductor inside a commercial building to the metering point but will stop
secondary conductors at a point outside of a building.
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3.3.4 Transformer Delivery Point
Customer Responsibility, Supply and install
 Concrete transformer pad. See drawing Section 3.4.1 for details:
 Pedestal mounted meter enclosure and conduit. See drawing Section 3.4.2 for details:
 Service conduit and conductor to the secondary section of the transformer.
 Customer provided secondary conductors must extend minimum of 6 feet from top of ground sleeve
for landing on secondary spades.
 Install Avista supplied ground rod in low voltage side of transformer.
 Install Avista supplied ground sleeve which creates a conduit window in the poured concrete
transformer pad.
 Bollards to protect transformer from being struck by vehicle traffic. Refer to Section 3.3.7 for details.
Avista Responsibility: Supply and Install,
 Transformer
 Current Transformers and wiring as required.
 Meter(s)
 Lugs to land customer conductor on the transformer secondary spades. See Section 3.4.4 for
allowed secondary conductors.
3.3.5 Delivery Point at Secondary Enclosure
Customer Responsibility, Supply and install
 Install Avista provided box pad for secondary enclosure See Section 3.4.3 for details.
 Pedestal mounted meter enclosure and conduit See Section 3.4.2 for details:
 Conduit and conductor from the building to the secondary enclosure and conduit from transformer to
enclosure.
 Customer provides enclosure and concrete pad if above 3000A and must get Avista engineering
approval on design.
Avista Responsibility: Supply and Install,
 Transformer
 Provide a Standard 3000 amp diversified load rated secondary enclosure and associated box pad.
 Current Transformers and wiring as required.
 Meter
 Lugs and land customer conductor on the secondary enclosure bus. Customer landing
area is on the bus end away from the transformer see Section 3.4.4.
 Land and install conductor between the transformer and secondary enclosure.
3.3.6 Building Delivery Point
Customer Responsibility, Supply and install
 Contact your local office for conduit and ditch requirements.
 Concrete transformer pads for three phase transformers. See drawing in Section 3.4.1: Note; meter
enclosure shown in this drawing is not required.
 Required metering equipment. See Section 4.0 Metering Requirements for information on metering
equipment needed for various service sizes.
 EUSERC rated Pulling/termination enclosure or external Switch board as needed.
Avista Responsibility: Supply and Install,
 Transformer
 Current Transformers and wiring as required
 Meter(s)
 Install and connect secondary conductors to both transformer and at service delivery point.
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Self-Contained Meters
Avista will terminate service lateral conductors in the meter socket.
Instrument Rated Meters
Avista will terminate service lateral conductors in the current transformer cabinet.
Self-Contained Meter Modules
2 – 6 Units:
Avista will terminate service conductors on the bus of a 2 to 6 meter modules.
More than 6 Units:
Avista will terminate at the main disconnect feeding several multiple meter modules.
Multi-Meter: Combination CT & Self-contained
Avista will terminate in a wall mounted termination/pull box or disconnect supplying individual self contained
or instrument rated meters. See enclosure requirements in the Section 4.0 Meter Requirements Section.

Switch Board
Avista will terminate in the termination/pull section of switch boards located outside. An option in this case is
for the customer to install, own and maintain service conductors from the building to Avista transformer.
Switch boards shall meet EUSERC requirements with manufacturing drawings to be preapproved by Avista.
See requirements in Section 4.4.7 Switchboard Metering.
Multiple Transformers
Contact Avista for design requirements when multiple pad mount transformers are used.
3.3.7 Vehicle Barriers
The customer may be required to install bollards or other vehicle barriers to protect the transformers,
padmounted equipment or meter equipment if they cannot be set 5’ back from curb or are in an area subject
to vehicle traffic. Contact Avista for information regarding bollard placement, spacing. Removable bollards
are not acceptable.

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SCOPE: This standard provides guidance for installation of bollards when protection is required for
padmounted equipment.

Figure 24- Bollard Clearances

AVISTA Utilities Distribution Standards DU-4.234 ESR Page 1 of 3
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Figure 25- Bollard Construction

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NOTES:
N1. The installation of bollards (Guard Posts) may be required when electrical
equipment is exposed to vehicular traffic or minimum clearances around
equipment cannot be met.
N2. The customer is responsible for supplying, installing, and maintaining bollards when required by an
Avista Utilities representative. Avista will supply and install bollards only to protect previously installed
equipment.
N3. See detail on page 1 for clearances to padmount equipment.
N4. If large equipment such as a three-phase transformer or padmount capacitor bank requires bollards for
protection, and if the five (5) foot spacing between bollards cannot be obtained while maintaining
adequate clearance, a single third bollard may be installed subject to the following provisions:
a. There must be a clear possibility of vehicle strikes to the equipment.
b. The bollard must be installed in line with the line between the doors on the equipment (three
phase transformers doors do not typically meet at the exact center of the equipment but are
displaced to the right.
c. The bollard must be installed sufficiently far away from the equipment cabinet so as not to
interfere with door opening.
d. Removable bollards are not permitted.
N5. Plastic tube 8” bollards filled with concrete are preferred for the protection of Avista Utilities equipment.
Steel bollards are not allowed within 6 feet or on access side of Avista equipment. They are easy to
install, yellow in color, maintenance free and locally available (Graybar and Anixter Power Solutions)
and do not require bonding to the equipment cabinet. All other bollards must be approved by an Avista
Utilities representative.
N6. Follow manufacturer's installation instructions. The hole for the bollard should be
3 ft 10 in deep. Setting depth is not critical so long as the bottom of the top section
of the bollard is below the ground line.
N7. Bollards shall be a minimum of 48 inches tall. If several bollards are needed, they
shall be placed at a maximum of 5' on center from each other.

REFERENCES:
R1. Refer to WAC 296-46B-450(f).
R2. Refer to DU-4.512 Grounding/Bonding of Adjacent Equipment.

AVISTA Utilities Distribution Standards DU-4.234 ESR Page 3 of 3
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3.3.8 Handholes

Handholes are to be used at the discretion of Avista for maintenance or repair of the utilities existing facilities.
Contact Avista’s Customer Project Coordinator for approval.
Lids:
Marked “Electric”
Secured using 7/8” (head size=0.0845”) pentahead bolts with captive nuts
Non skid surface.
High density polyethylene, ABS plastic, or polymer concrete.
Exception: Metallic lids if bonded to ground using methods approved by the local electrical inspector.
Material:
High density polyethylene, ABS plastic, polymer concrete or concrete as required for strength.
Strength:
Non-traffic loading minimum 350 lbs/sqft
Incidental traffic minimum H-20 rating. (Not for road applications)

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3.4 PADMOUNTED EQUIPMENT DRAWINGS
3.4.1 Three-Phase Transformer Concrete Pads

Figure 26- Three Phase Transformer Concrete Pads

AVISTA Utilities Distribution Standards DU-5.122 ESR Page 1 of 2
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Table 5- Three Phase Transformer Concrete Pad Dimensions
NOTES:
N1. Direction of entry of high voltage conduits may vary according to the job requirements.
N2. Service conduits must be installed prior to forming and pouring the pad to avoid undermining the pad.
N3. Service conduits must be confined to the low voltage side of the window.
N4. When the number of secondary conductors exceeds the limits in DU-5.124, Avista Utilities will provide a
secondary enclosure.
N5. A ground sleeve will be supplied by Avista Utilities. It shall be centered left to right in the pad.
N6. For transformers larger than 500 kVA, the customer will be required to provide a larger concrete pad.
N7. The meter pedestal shall be located as specified by Avista Utilities Electric Meter Shop. The rigid upright
steel conduits for metering enclosure shall be set in concrete and be capped with steel cap.
N8. Pad shall be located and oriented as specified by Avista Utilities (R2).
N9. Pad shall be constructed on firm undisturbed or well-compacted earth, shall be bedded on 3” of
compacted ¾” gravel and shall be level.
N10. Concrete shall be 5-bag mix with 3/4 inch maximum size aggregate. Top surface shall be broom
finished. Edges shall be rounded.
N11. Concrete shall be at least 4 inches thick and shall be reinforced at half the depth with #4 rebar on 12
inch centers each way. Reinforcing extending around window shall consist of a minimum of 2 rebars.
N12. 2" steel pipe poles should be bonded to transformer ground.
N13. Concrete pad installations must be inspected by Avista before pad is poured and again after pad is
poured.
N14. Install 1” conduit for metering 6” maximum from back of opening on customer side.

REFERENCES:
R1. Avista Utilities Electric Service and Meter Requirements manual.
R2. Refer to Clearances to Other Equipment, Buildings, and Swimming Pools DU-4.222.
R3. Refer to Underground Standard DU-5.120.
R5. Refer to DU-9.215 Pedestal Mounted Meter Enclosure.

AVISTA Utilities Distribution Standards DU-5.122 ESR Page 2 of 2
3-PHASE
KVA DIMENSIONS IN INCHES UNIT ASSEMBLY
A B C H L
45-500 80 90 18 40 25 GNDSLV3
750-1500 90 132 24 40 25 GNDSLV3LRG
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3.4.2 Pedestal Mounted Meter Enclosure – For Dedicated Transformer

Figure 27- Pedestal Mounted Meter Enclosure for Dedicated Transformer

AVISTA Utilities Distribution Standards DU-9.215 ESR Page 1 of 1
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2017 Electric Service Requirements 01/18/2017 Page 69

3.4.3 Secondary Enclosures

Figure 28- Secondary Enclosure Fiberglass Box Pad

AVISTA Utilities Distribution Standards DU-5.123 ESR Page 1 of 3
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Figure 29- Secondary Enclosure Poured In Place Concrete Pad

AVISTA Utilities Distribution Standards DU-5.123 ESR Page 2 of 3
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2017 Electric Service Requirements 01/18/2017 Page 71

NOTES:
N1. When the number of secondary conductors exceeds the limits in DU-5.124, Avista will
provide a standard 3000A secondary enclosure and box pad. Sizes other than the standard enclosure
and box pad shall be provided by the customer.
N2. Pad shall be located and oriented as specified by Avista Utilities (R2). The bus in the
secondary enclosure will be the point of service as defined in Avista Utilities rates and tariffs.
N3. Pad shall be constructed on firm undisturbed or well-compacted earth, shall be bedded
on gravel and shall be level.
N4. Concrete shall be 5-bag mix with 3/4 inch maximum size aggregate. Top surface shall
be broom finished. Edges shall be rounded.
N5. Concrete shall be at least 4 inches thick and shall be reinforced at half the depth with #4
rebar on 6 inch centers each way. Reinforcing shall extend around window.
N6. Direction of entry of utility conduits may vary according to the job requirements.
N7. Conduits must be installed before fiberglass box pad installation or before forming and
pouring the pad to avoid undermining the pad.
N8. The meter pedestal shall be located as specified by Avista Utilities. The rigid conduits shall be set in
concrete. Avista Utilities Meter Shop will determine CT applications. Meter location may vary with
specific application. Leave room to open enclosure doors.
N9. Conduit between transformer and enclosure may be a gutter in some applications.
N10. A separate ground conductor (3/0 copper) must be installed between the transformer
ground rod and the enclosure ground rod.
N11. Area between transformer concrete pad and secondary enclosure box pad or concrete
pad can be concrete. Leave enough room for setting transformer.
N12. Seal the source side conduit where customer conduits enter a building. Fire barrier water-tight sealant
SN 668-0600 with fire barrier packing material SN 668-0601 if needed.
N13. Alternate meter location must be approved by Avista before installation.

REFERENCES:
R1. Avista Utilities Electric Service and Meter Requirements manual.
R2. Refer to DU-5.020, Transformer Clearances.
R3. Refer to DU-5.124, Secondary Enclosure Padmount.
R4. Refer to DU-5.122, Concrete Pads Three-Phase Transformers.
R5. Refer to DU-9.215, Pedestal Mounted Meter Enclosure.

AVISTA Utilities Distribution Standards DU-5.123 ESR Page 3 of 3

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3.4.4 Padmounted Secondary Enclosure

AVISTA Utilities Distribution Standards DU-5.124 ESR Page 1 of 3
Figure 30- Padmounted Secondary Enclosure
Staff_PR_094 Attachment A Page 73 of 110

2017 Electric Service Requirements 01/18/2017 Page 73

TRNSF
KVA
FULL
LOAD
AMPS
SEC
VOLTS
REC MAX
CUST SEC
WIRES PER
PHASE FROM
TRNSF (N6)
CONDUITS
FROM
TRNSF
TO ENCL
PHASE & NEUTRAL WIRES FROM
TRANSF TO SEC ENCLOSURE (N3,
N8)
45 125 208Y/120 3 2-3” PVC 1 x 2/0 AL Quadruplex
75 210 208Y/120 3 2-3” PVC 1 x 350 AL Quadruplex
112.5 315 208Y/120 3 2-4” PVC 1 x 750 AL (500 CU) PH & 1 x 350 Neut
150 415 208Y/120 3 3-4” PVC 2 x 350 AL Quadruplex
225 625 208Y/120 4 3-4” PVC 2 x 750 AL (500 CU) PH & 2 x 350 Neut
300 835 208Y/120 6 5-4” PVC 3 x 750 AL (500 CU) PH & 3 x 350 Neut
500 1390 208Y/120 6 7-4” PVC 5 x 750 AL (500 CU) PH & 5 x 350 Neut
750 2080 208Y/120 8 9-4” PVC 7 x 750 AL (500 CU) PH & 7 x 350 Neut
1000 2775 208Y/120 9 9-4” PVC 9 x 750 AL (500 CU) PH & 9 x 350 Neut

45 54 480Y/277 3 2-3” PVC 1 x 2/0 AL Quadruplex
75 90 480Y/277 3 2-3” PVC 1 x 2/0 AL Quadruplex
112.5 135 480Y/277 3 2-3” PVC 1 x 2/0 AL Quadruplex
150 180 480Y/277 3 2-3” PVC 1 x 4/0 AL Quadruplex
225 270 480Y/277 4 2-4” PVC 1 x 350 AL Quadruplex
300 360 480Y/277 6 2-4” PVC 1 x 750 AL (500 CU) PH & 1 x 350 Neut
500 600 480Y/277 6 3-4” PVC 2 x 750 AL (500 CU) PH & 2 x 350 Neut
750 900 480Y/277 8 4-4” PVC 3 x 750 AL (500 CU) PH & 3 x 350 Neut
1000 1200 480Y/277 9 6-4” PVC 4 x 750 AL (500 CU) PH & 4 x 350 Neut
1500 1800 480Y/277 9 6-4” PVC 6 x 750 AL (500 CU) PH & 6 x 350 Neut
Table 6- Conduits and Conductors From Transformer to Secondary Enclosure

NOTES:
N1. When the customer has more cables to terminate than the recommended number of cables per phase
from the transformer, as shown in the table above, a padmount secondary enclosure shall be installed.
The Avista provided secondary enclosure should be placed onto a fiberglass box pad (R3) where
conditions permit. If use of a box pad for the secondary enclosure is not practical, the customer shall
provide a concrete pad for the transformer and the secondary enclosure (R4).
N2. The customer must provide conduits between the transformer and the secondary enclosure to
accommodate the connecting cables.
N3. Three-phase conductors and one neutral conductor shall be installed in each conduit.
N4. Install cables shown in the table above to obtain full transformer capacity.
N5. Bond the enclosure case to the enclosure ground rod with two - 2/0 conductors.
N6. The customer's cables should be no larger than 750 CU or 1000 AL when terminated in the secondary
enclosure.

N7. Avista will furnish and install lugs on the secondary and service conductors and land those conductors
on the secondary enclosure terminals.

AVISTA Utilities Distribution Standards DU-5.124 ESR Page 2 of 3

Staff_PR_094 Attachment A Page 74 of 110

2017 Electric Service Requirements 01/18/2017 Page 74

NOTES (cont.):
N8. This column lists the number and size of secondary conductors recommended between the transformer
and junction enclosure. It does not apply to longer service runs where voltage drop may be a
consideration. These recommendations are based on the ampacities listed in DU-7.101. The
secondary conductors are sized to meet both the summer and winter ratings of the transformer, taken
as 114% and 160% of the OA rating respectively.
N9. Transformer ground rod and secondary enclosure must be bonded together with a 3/0 CU conductor.
N10. Table values allow ability to go up one transformer size.
N11. Where customer conduits enter a building, the secondary conduits must be sealed below the secondary
enclosure and where the conduits enter the building wall. Use fire barrier water-tight sealant SN 668-
0600 with fire barrier packing material SN 668-0601.
N12. When a secondary enclosure is installed, the point of delivery will generally be the bus bars in the
secondary enclosure (R4). Avista will install lugs at point of delivery. No CT’s will be installed in
secondary enclosures.
N13. Secondary enclosure has not been UL approved and is owned by Avista.

REFERENCES:

R1. NESC 374, NESC 384
R2. NESC 96C
R3. Refer to DU-5.123, Fiberglass or Concrete Pads Secondary Enclosure.
R4. Refer to Avista Utilities Electric Service and Meter Requirements manual.
R5. Refer to DU-7.203, Heavy Duty Lugs.
R6. Refer to DU-7.101, Secondary Cable Characteristics.
R7. Refer to DU-5.122, Concrete Pads Three-Phase Transformer.

AVISTA Utilities Distribution Standards DU-5.124 ESR Page 3 of 3
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Conduit Entrance Single-Phase Transformer

Figure 31- Conduit Entrance Single-Phase Transformer 
NOTES:
N1. Backfill trench for 8 to 10 feet, one foot deep, on all sides of enclosure to anchor primary conduit (R5).
N2. Seal unused conduits with plastic conduit caps.
N3. Other conduit arrangements may be required depending on the situation.
REFERENCES:
R1. NESC 321B.
R2. NESC 360B.
R3. NESC 361A.
R4. NESC 363A.
R5. Refer to DU-3.202 and DU-3.212 for junction enclosures.

AVISTA Utilities Distribution Standards DU-4.750 ESR Page 1 of 1
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Conduit Entrance 1&2-Phase Padmounted Junction Enclosures

Figure 32- Conduit Entrance 1 & 2 Phase Padmounted Junction Enclosures

NOTES:
N1. Backfill trench for 8 to 10 feet, one foot deep, on all sides of enclosure to anchor primary conduit (R5).
N2. Seal unused conduits with plastic conduit caps.
N3. Other conduit arrangements may be required depending on the situation.

REFERENCES:
R1. NESC 321B.
R2. NESC 360B.
R3. NESC 361A.
R4. NESC 363A.
R5. Refer to DU-3.202 and DU-3.212 for junction enclosures.

AVISTA Utilities Distribution Standards DU-4.751 ESR Page 1 of 1
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2017 Electric Service Requirements 01/18/2017 Page 77

3.4.5 Conduit Entrance 3-Phase Padmounted Junction Enclosures

Figure 33- Conduit Entrance 3-Phase Padmounted Junction Enclosures

NOTES:
N1. Backfill trench for 8 to 10 feet, one foot deep, on all sides of enclosure to anchor primary conduit (R4).
N2. Seal unused conduits with plastic conduit caps.
N3. Other conduit arrangements may be required depending on the situation.

REFERENCES:
R1. NESC 321B.
R2. NESC 360B.
R3. NESC 361A.
R4. NESC 363A.
R5. Refer to DU-3.202 and DU-3.212 for junction enclosures

AVISTA Utilities Distribution Standards DU-4.752 ESR Page 1 of 1
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2017 Electric Service Requirements 01/18/2017 Page 78

4.0 METERING REQUIREMENTS
4.1 GENERAL
Only Avista owned metering equipment will be used to provide billing information.
The customer must provide Avista with access for meter reading, maintenance, installation or removal per
WAC 480-100-168.
Consideration shall be given to the safety of Avista employees who must install, test, and read the meters on
a regular basis.
WORK SPACE SHALL BE PROVIDED AROUND THE METERING EQUIPMENT AND KEPT CLEAR AT
ALL TIMES. MINIMUM SPACE SHALL BE 15" ON BOTH SIDES OF THE METER DOWN TO GRADE.
MINIMUM FRONTAL CLEARANCE IS 36" PER NATIONAL ELECTRIC CODE.
4.1.1 Listing
All meter sockets, enclosures shall be listed by a qualified electrical testing laboratory acceptable to the
jurisdiction having the authority.
4.1.2 Location
Metering equipment locations are subject to the following; Exceptions must be approved through the Avista
Meter Department.
 The meter must be located as close as practical to the delivery point.
 Located on the line side of the service disconnect (Hot sequence).
 Each customer premise will be supplied through a single meter.
 At a multi-meter service point, meters will be grouped at one location with all meters located as
closely as practical to the service point (within 25 feet of each other).
 Meters must be grouped together and installed at the service equipment and not separated by walls
or partitions.
 Located outdoors or in approved meter rooms with permission from the Avista Electric Meter
Department. No metering equipment shall be installed at a service switch located in an inaccessible
place such as a manhole or in a vault.
 Marijuana grow operations must have service meters located outside of building.
 Readily accessible, free from vibration, corrosive atmosphere, abnormal temperatures, and well lit
per WAC-480-100-308
 Whenever the customer makes additions, or changes that encloses the meter and prevents access
they may be required to relocate the metering equipment, at their expense, to meet Avista’s
specifications.
 Meters must be protected from ice and water off roofs, damage from doors and materials and
vehicular traffic.
 No Meters are allowed downstream of customer equipment such as dry transformers.
 Meters in backyards (opposite roadway) where address is not visible must have address labelled on
meter can with weatherproof decal.
4.1.3 Meter Room Requirements
 Must meet all electrical and mechanical code requirements.
 Meters must be grouped together in the same room. Not separated by walls or partitions.
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 Located on the ground floor with exterior doors opening outward with direct access to meters.
Exceptions require prior approval through Avista Electric Meter Shop.
 The exterior door shall be equipped with a panic bar.
 If locked, the customer will provide a key for an Avista installed lock box.
 Area must be well lit and not used for storage.
 3 ft working clearance is required in front of each meter and 15” on both sides of meter enclosures.
 Avista will no longer run secondary conductors into customer’s commercial or multi residence
building through the wall or up through the slab. Going forward the “Point of Delivery” will be in an
outside wall mounted Pulling/termination enclosure or a standalone Pulling/termination enclosure
away from the building wall installed on (2) 2 inch rigid steel pipe embedded in concrete with unistrut
for attachment points as needed.
4.1.4 Meter Identification
For multi-unit dwellings with a separate meter for each customer all meter sockets must be marked. The
equipment installer / electrician are responsible to provide a label with the unit number or address. A house
meter for common facilities must be marked as “House Meter”. Marking must be complete before meters
can be installed.
Labels shall be of a engraved or embossed type, minimum size ½” x 2” engraved plastic with sticky back.
Letters or numbers must be a minimum of 5/16”. Individual screw on house numbers/letters will not be
accepted.
Common gas and electric meters must have the same space designation marking; i.e., numbers or letters.
Avista will not install any meters at multi-metered facilities until each individual meter is properly
labeled AND each circuit is physically verified jointly by the installing electrician and Avista’s meter
installer. The building owner must provide Avista’s meter installer or Customer Project Coordinator
with a floor plan or similar document clearly identifying each unit’s physical location and address in
order to perform this physical audit prior to meter installation.
The building owner is responsible for proper identification of electric and gas meters. The building owner
could be held responsible for Avista costs associated with correcting billing errors caused by mixing wiring or
mislabeled meters.
If two electric services service one building or space, a warning tag must be located at each meter point
indicating such. Refer to NEC Article 230.2E.
Labels, as described above, marked with voltage and phasing information are required if two or more
services with different voltages or phasing are supplied to a building.
4.1.5 Security
 No conduit bodies are allowed ahead of meter.
 All removable enclosure covers or doors, raceways or conduits containing unmetered conductors
shall be sealable for locking by Avista.
 Factory installed carriage bolts may be used to seal panel covers that do not require field removal.
 Only rain tight enclosure doors may cover the sealed areas.
 Sealable latches, stud and wing-nuts, or sealing screws shall be used to seal removable doors.
 Acceptable sealing devices;
1) Stud and wing-nut assemblies, ¼ inch x 20 (minimum). The stud and associated wing-nut
shall have 0.0635 inches holes. 2) Sealing screws with 0.0635 inch holes.
4.1.6 Meter Mounting
Meter sockets and/or enclosures must be plumb and level and securely mounted to a rigid surface.
Mounting to metal siding only is not acceptable.
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If a meter socket is to be mounted to a post or pole, it must be mounted on C-channel securely fastened to
the pole/post.
All 480V 200 amp self contained meter cans that are stand alone and not attached to a building must be
mounted on unistrut attached to two 2 inch rigid steel pipes (with threaded steel caps) imbedded in concrete.
Stand alone 400 amp single phase 120/240V self contained meter cans with additional 200 amp breaker
boxes mounted alongside the meter can must be mounted on unistrut attached to two 2 inch rigid steel pipes
(with threaded steel caps) imbedded in concrete.
400 amp single phase self contained meter cans with a 400 amp main breaker and no additional breaker
boxes alongside can still be mounted on unistrut attached to a full treated 6”x6” post imbedded in concrete.
On stone or brick veneer, meter sockets must be flush-mount or surface-mount and not recessed behind the
brick or stone.
Single meters shall be installed between four and six feet to the center of the meter above the floor or
finished grade. Meter modules shall be installed no more than six feet to the center of the top meter and not
less than 24 inches to the center of the bottom meter.
4.1.7 Lifting Handles
When lifting handles are required on panels and covers of enclosures, each handle shall be sized for full
hand grasping, securely attached and designed to support 75 lbs. Chest type handles with a folding bale
grasp are not acceptable.
4.1.8 Sprinkler Service
120V/240 volt sprinkler services must be provided instead of 120 voltage single phase. UL listed
combination meter socket and breaker panel are not available for 120V single phase service.
4.2 SELF CONTAINED METERING
4.2.1 Manual Circuit Closing (MCC) Sockets
Manual circuit closing, MCC sockets allow the meter to be removed without interruption of the electrical
service. When required they must be in working condition. Wiring in the socket must not interfere with the
operation of circuit closers. MCC sockets must be approved by Avista.
The following services require MCC Sockets: (exceptions by permission only)
 All commercial services including meter modules.
 All 480V services and pumps require MCC safety sockets.
 400 A residential services, optional on 200 permanent or temporary services.
 House meters serving common area in apartment buildings.
 Commercial signs.
 Irrigation controls.
 Pumps.
 Interconnected Customer Generators.
 Meter modules with slide type and horn style bypasses are NOT approved.

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4.3 METERING EQUIPMENT RATINGS AND TYPE
4.3.1 Approved Self-Contained Sockets
REQUIRED METERING EQUIPMENT
SERVICE VOLTAGE SERVICE CAPACITY
AMPERES METERING EQUIPMENT

Single-phase
Up to 100 4 terminal 100 amp socket
101 to 200
4 terminal 200 amp socket
MCC required for commercial
MCC optional for residential
201 to 400 4 terminal 400 amp MCC socket
401 to 1,000
Residential
See 1 Phase instrument transformer
metering. DO-7.313 1/3, Section 4.4.8
Electric Serv. Requirements
4 Wire three-phase 120-240 Delta
identify high leg to ground with
orange tape and be connected to
right side of meter or CT platform
Up to 200 7 terminal, 200 amp, manual circuit
closing socket
201 to 1,000
See 3 Phase instrument transformer
metering. DO-7.313 2/3, Section 4.4.8
Electric Serv. Requirements
(Network) Single-phase 120-208
Wye 3 Wire
Up to 100 5 terminal, 100 amp socket
101 to 200 5 terminal, 200 amp socket
201 to 1,000 Instrument transformer metering Avista
installs meter and enclosure
4 Wire, three-phase 120-208 Wye
Up to 200 7 terminal, 200 amp MCC socket
Over 200
See 3 Phase instrument transformer
metering. DO-7.313 2/3, Section 4.4.8
Electric Serv. Requirements
4 Wire, three-phase 277-480 Wye
(N1)
Up to 200 7 terminal, 200 amp MCC safety
socket
Over 200
See 3 Phase instrument transformer
metering. DO-7.313 2/3, Section 4.4.8
Electric Serv. Requirements
Switchgear All Voltages All
Manufacturer supplied 13 terminal Pnl
Mounted Socket w/ Test Switch
Mounts
Avista Supplies Flush Mounted 13
Terminal Meter w/ Trim Can
Table 7- Self-Contained Socket Required Metering Equipment
NOTES:
N1. Three-Wire, three-phase, 480 volt delta is no longer available on new services.
N2. One hundred (100) amp, three-phase, four-wire sockets are not allowed because of
inadequate clearances.
N3. 480V Self-Contained require a safety socket.

AVISTA Utilities Distribution Standards DO-7.315/DU-9.315 ESR Page 1 of 2

Staff_PR_094 Attachment A Page 82 of 110

2017 Electric Service Requirements 01/18/2017 Page 82

Notes:
1. Commercial meter sockets not listed must be individually approved by Avista’s
meter department.
2. Meter modules with slide type and horn style bypasses are not
approved.
3. 480V Self-contained require a safety socket.
4. Avista will not hook up overhead meter sockets being used for underground
service, even if they have been approved by the local authority having jurisdiction
– (They do not have adequate horizontal space).
AVISTA Utilities Distribution Standards DO-7.315/DU-9.315 ESR Page 2 of 2
Staff_PR_094 Attachment A Page 83 of 110

2017 Electric Service Requirements 01/18/2017 Page 83

4.3.2 Self-Contained In-Line Socket Diagrams

Figure 34 - Self-Contained In-Line Meter Socket Diagrams

AVISTA Utilities Distribution Standards DO-7.314/DU-9.314 ESR Page 1 of 1
Staff_PR_094 Attachment A Page 84 of 110

2017 Electric Service Requirements 01/18/2017 Page 84

4.4 INSTRUMENT TRANSFORMER METERING
Current transformers meter and wiring are provided by Avista. The customer provides solidly mounted
approved meter enclosures or sockets, current transformer enclosures, and conduit.
4.4.1 Current Transformer Location
CT’s are normally mounted in an enclosure located on the building.
At Avista's option, current transformers may be mounted in a three-phase pad mount transformer that is
dedicated to only one customer. In this case the meter enclosure is mounted next to the pad or in an
approved location.
CTs will not be mounted in single phase pad transformers.
On overhead transformers larger than 300KVA Avista would prefer to locate CT’s at the transformers on the
rack.
4.4.2 Metering Conduit Requirements
 Conduit length must be such that wire length between meter(s) and current transformer(s) is less
than thirty feet.
 1 inch gray electrical PVC.
 Schedule 80 PVC above or below grade, rigid above grade.
 Minimum sweep radius is 9”.
 Maximum of two 90 degree sweeps.
 Bushings are required at both ends of the conduit run. The local inspector may require grounding
bushings.
 The ends of the conduit must be taped or capped, and sealed to keep dirt and water out of the
conduit. Customer is responsible for any obstructions within the conduit.
 All conduit connections must be glued and fully seated and a pull string installed if there is more than
20’ of one inch conduit.
4.4.3 CT Enclosures - General Requirements
 Weatherproof .
 The conduit must enter in the bottom of the enclosure or on the side within 2" of the bottom with a
rain tight fitting if service is fed from underground.
 Conduit may enter top of enclosure if service is fed from overhead provided rain tight fittings are
utilized.
 Enclosures cannot be used as junction boxes or raceways.
 Lockable.
 Each CT metered service requires its own CT enclosure and meter enclosure or socket.
 Avista will no longer allow or hookup new or repaired CT enclosures mounted on plywood. Unistrut
type cross struts are the required attachment points for enclosures.
 CT cans must have a hinged door with fixed handles for removing.

4.4.4 Multi-Meter: Combination CT & Self-contained
A multi-meter building served using a combination of individually mounted CT rated, self-contained, and/or
meter modules requires a pulling/termination enclosure to provide a single point of delivery. Individual
Staff_PR_094 Attachment A Page 85 of 110

2017 Electric Service Requirements 01/18/2017 Page 85

meters shall be located as close as physically possible, but no case more than 25 ft from the point of
delivery. The utility compartment of the enclosure must meet the requirements below.
4.4.5 Pulling/Termination Enclosure Utility Space

Figure 35- Pulling/Termination Enclosure Utility Space 

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2017 Electric Service Requirements 01/18/2017 Page 86

Approved EUSERC Rated Termination Enclosures (utility underground pull boxes)
Service Amperage # of Phases Buss type Manufacture Model #
------------------------- -------------- -------------- ------------------- --------------
201-400 1 Feed Thru Cooper B-Line R9000C
201-400 1 Feed Thru Eaton 1UGPB400R
401-800 1 Feed Thru Cooper B-Line R9000E
401-800 1 Feed Thru Eaton 1UGPB800R
801-1200 1 Feed Thru Cooper B-Line R9000F
801-1200 1 Feed Thru Eaton 1UGPB1200R
1200 1 Feed Thru Siemens WT11200PU
201-400 3 Feed Thru Cooper B-Line R9000CC
201-400 3 Feed Thru Eaton 3UGPB400R
401-800 3 Feed Thru Cooper B-Line R9000EE
401-800 3 Feed Thru Eaton 3UGPB800R
801-1200 3 Feed Thru Cooper B-Line R9000FF
801-1200 3 Feed Thru Eaton 3UGPB1200R
1200 3 Feed Thru Siemens WT31200PU
1600 3 Feed Thru Erickson TB-469N (NON- EUSERC)
--------------------------------------------------------------------------------------------------------------------------------
201-400 1 Hor. Cross Buss Siemens WET1400BU
401-800 1 Hor. Cross Buss Siemens WET 1800BU
801-1200 1 Hor. Cross Buss Siemens WET11200BU
201-400 3 Hor. Cross Buss Siemens WET3400BU
401-800 3 Hor. Cross Buss Siemens WET3800BU
801-1200 3 Hor. Cross Buss Siemens WET31200BU
4.4.6 Notes
1. The area below the load side lugs is reserved for utility conductors only. Customer conductors
cannot pass through the utility’s section of the cabinet.
2. Terminating facilities for utility conductors shall be aluminum-bodied mechanical lugs with a range
accepting a single #4AWG through 750KCMIL or two #1AWG through 250KCMIL conductors.
Number of lugs for each current range is listed above.
3. Avista will supply and install line side lugs.
4. Lugs shall be secured to prevent turning or misalignment.
5. The minimum pull box access opening (W) is measured between the left and right.
6. Enclosure covers shall be removable, sealable, provided with two lifting handles, hinged and limited
to the maximum size of 9 sqft. Note general sealing requirements above.
7. All customer conduit, sealable conduit, or solid bus bars must exit above utility side
connections and all fittings must be weathertight type.
8. Utility conduits shall enter termination enclosure from the bottom.
9. Termination enclosure must be EUSERC rated and approved.
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4.4.7 Switchboard Metering
A EUSERC approved switchboard metering section is required for service ratings greater than 800 amperes at
building delivery points. They are also normally used for single points of delivery with a combination of self-
contained and instrument transformer rated services exceeding 1200 amperes.
Prior to manufacture contact Avista Utilities for approval of manufactures drawings and to determine
the type of metering, size of current transformers and mounting arrangements.
 Meets EUSERC recommendations.
 All unmetered conductors in separate, sealable, and lockable compartments.
 Must have an accessible instrument transformer mounting section.
 13 terminal socket and test switch slots if CT metered.
 7 terminal socket if self-contained.
 Termination section approved for utility connection.
 Mechanical or compression lug.

Figure 36- Typical Switchboard Multi-Meter Layout

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4.4.8 Single Phase Current Transformer Metering
1 PHASE CURRENT TRANSFORMER METERING
OVERHEAD AND UNDERGROUND
401 TO 800 AMPS RESIDENTIAL & COMMERCIAL

Figure 37- 1 Phase Current Transformer Metering 401 to 800 Amps
           CT Enclosure
 Removable hinged door(s) * Type 3R, ANSI 61 gray
w/sealing and locking provisions

Service Ampacity WxHxD Cooper B-Line Milbank Hoffman
201-400 AMP 30X30X11 inches 303011RTCT CT303011SC A303011CT
401-800 AMP 36X48X11 inches 364811HRTCT CT364811HC A483611HCT

CT Landing Platforms
Part #’s or Equivalent
 Forbar type ANSI C12.11 CT’s * 600V, 50kA AIC
 Line & Load side Mechanical Lugs

Service Ampacity WxHxD Cooper B-Line Milbank
201-400 AMP 30X30X11 inches 6019 HAL K4903
401-800 AMP 36X48X11 inches 6019 HEL K4729

Approved 6 Terminal, 100A Meter Socket
Manufacturer Part #
COOPER B LINE U121315-50365
MILBANK U3504XL Plus (2) 5T8K2

NOTES:
N1. The customer supplies and installs the current transformer enclosure,
mounting base, meter enclosure. Avista supplies and installs the current
transformers, instrument wiring and meter.
N2. Current transformer enclosure must be bonded and grounded per NEC requirements by customer.
N3. Avista will supply, install, and connect conductor to the line side only on
UNDERGROUND services. The customer supplies, installs and connects
conductor on OVERHEAD services.
N4. Customer supplies landing lugs for Avista conductors on UNDERGROUND
services.
N5. CT landing platforms are rated on diversified load.
N6. Inside commercial grow operations cannot exceed 800 amps of true load on single phase service.
AVISTA Utilities Distribution Standards DO-7.313 ESR Page 1 of 2
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2017 Electric Service Requirements 01/18/2017 Page 89
4.4.9 Three Phase Current Transformer Metering
3 PHASE CURRENT TRANSFORMER METERING
OVERHEAD AND UNDERGROUND 201 TO 800 AMPS
Figure 38- 3 Phase Current Transformer Metering 201 to 800 Amps
CT Enclosure
Removable hinged door(s)* Type 3R, ANSI 61 gray
w/sealing and locking provisions
Service Ampacity WxHxD Cooper B-Line Milbank Hoffman
201-400 AMP 36X36X11 inches 363611HRTCT CT363611HC A363611HCT
401-800 AMP 36X48X11 inches 364811HRTCT CT364811HC A483611HCT
400 -1200AMP 48X48X12 inches A1200NECT*
*Includes Landing Platform
CT Landing Platforms
Part #’s or Equivalent
Forbar type ANSI C12.11 CT’s * 600V, 50kA AIC
□Line & Load side Mechanical Lugs
Service Ampacity WxHxD Cooper B-Line Milbank
201-400 AMP 36X36X11 inches 6067 HAL K4904
401-800 AMP 36X48X11 inches 6067 HEEL K4722
NOTES:
N1. The customer supplies and installs the current transformer enclosure, mounting
base, meter enclosure. Avista supplies and installs the current transformer,
instrument wiring and meter.
N2. Avista will supply, install, and connect conductor to the line side only on
UNDERGROUND services. The customer supplies, installs and connects
conductor on OVERHEAD services.
N3. Hi leg/wild leg on 3 phase 4 wire delta services must be on the right hand side
CT landing platform.
N4 For alternate enclosure sizing contact Avista Meter Shop at [phone].
N5. Minimum of 15” of Clearance from latch side and 6” clearance on hinge side of Cooper B-Line or
Hoffman 351 Meter Can to CT Enclosure.
N6. Inside commercial grow operations with three phase service must be 120/208 or 277/480 volt.
N7. Current transformer enclosure must be bonded and grounded per NEC requirements by customer.
AVISTA Utilities Distribution Standards DO-7.313 ESR Page 2 of 2
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4.5 CELL TOWER METERING
Figure 39- Cell Tower Metering
These are general Avista Utilities requirements. The customer or their electrican must consult the local
electrical code authority for specific requirements. An electrical inspection permit must be displayed
before a service connection can be made.
NOTES:
N1 600 AMP pull box with position meter pac for 1 to 3 antenna arrays,
800 AMP pull box with 6 position meter pac for 4 or more antenna arrays.
N2 Manual circuit closing sockets required slide type bypasses are unacceptable.
N3 Avista will provide and install one set service conductors, lugs and meters.
N4 Customer to supply and install all other materials.
N5 Meter pack may be mounted on a building if desired.
N6 Avista lock is required on the gate to fence areas.
N7 Metering must be outside of area of high RF energy so prolonged exposure presents no health risk.
AVISTA Utilities Distribution Standards DO-7.312/DU-9.312 ESR Page 1 of 1
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2017 Electric Service Requirements 01/18/2017 Page 91
5.0 Service Voltages
Figure 40- Service Voltages
AVISTA Utilities Distribution Standards DO-6.302/DU-7.600 ESR Page 1 of 2
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2017 Electric Service Requirements 01/18/2017 Page 92

NOTES:
N1. Available service voltage is determined by Avista based on power and energy needs as well as the
supply system on hand in the area. Requests for service voltages, sizes and special applications other
than those listed should be referred to Distribution Engineering.
N2. Service voltage is measured at the point of delivery. This point is where Utility service conductors and
customer service entrance conductors are connected. Service voltage ranges may differ from those
listed during emergencies or for some rural customers because of the distance from the source.
Voltages may temporarily fluctuate outside the listed ranges as loads start and stop or during fault
conditions.
N3. Objectionable voltage variations caused by customer loads are corrected at customer expense.
N4. Record service voltage at the meter over several days with customer loads operating under stable but
maximum conditions to determine if they are within the allowable range. A single reading with a
multimeter will provide a quick check only. Normally changes should not be made by adjusting
transformer taps.
N5. Primary voltage may be measured by using the secondary of a lightly loaded or unloaded transformer.
Multiply by primary / secondary voltage ratio or the winding ratio if known.
N6. The utility system is designed and operated to limit the maximum voltage unbalance between phases. A
maximum of 3% is expected under normal conditions at the point of delivery of an unloaded service. All
three phase voltages must still be within the Service Voltage Range. Motors and other three phase
equipment may need to be derated for unbalance over 1%.

% Unbalance = Maximum Voltage Deviation from Average Phase Voltage
Average Phase Voltage

Example: For phase voltages of 230, 232, and 225, the average 229: the maximum deviation from
average is 4: and the percent unbalance is (100 x 4)/229 = 1.75 percent.

REFERENCES:
R1. ANSI C84.1 – 2006
R2. WAC 480-100-373
R3. Avista Utilities Schedule 70 Rule 5 "Definitions"
R4. Avista Utilities Schedule 70 Rule 16 "Continuity of Service"
R5. Avista Utilities Schedule 70 Rule 17 "Optional Phase and Voltage"
R6. Avista Utilities Electric Service and Meter Requirements

AVISTA Utilities Distribution Standards DO-6.302/DU-7.600 ESR Page 2 of 2
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2017 Electric Service Requirements 01/18/2017 Page 93
6.0 Customer Generation Requirements
There are two general forms of Customer generation. The first is interconnected with the utility system to
supply energy. The other is an emergency standby system.
6.1 Generation Interconnection
Whether you’re thinking about or moving forward with the installation of an electrical generating system,
Avista has put together the information you will need to interconnect to our system. In some cases, Avista
might also be able to offer a Renewable Generation Incentive (RGI) that provides direct payments to help
offset and recover costs of renewable energy systems in Washington State. More information on this
incentive can be found at:
http://www.avistautilities.com/services/renewable/incentives/Pages/default.aspx
Interconnection requirements are separated into two different types of systems.
The various documents required for interconnection differed by system category. Please be sure to read all
of the information, as approvals are required from Avista before generation can be interconnected with
the utility. If you have any questions, please contact the key contacts for either type of system.
Interconnection of systems 500 kW and less:
Contact: Tyler Dornquast
[e-mail] or call 509-495-4580.
Documents available through our key contact or at:
http://www.avistautilities.com/services/electricity/interconnection/Pages/default.aspx
Interconnection of systems between 500 kW and 20 MW
Contact: Warren Clark at:
[e-mail] or call 509-495-4186.
Documents available through our key contactor or at:
http://www.avistautilities.com/services/electricity/interconnection/Pages/default.aspx
Staff_PR_094 Attachment A Page 94 of 110
2017 Electric Service Requirements 01/18/2017 Page 94
Net-Meter Generation 100 kW or smaller in Washington and Idaho
□Submit an application with application fee to Avista Utilities
Interconnection inverter must be UL1741 listed.
Electrical schematic drawing must be included.
Include provisions for a lockable visible disconnect if required by Avista Utilities or local
jurisdiction.
□Send to: Tyler Dornquast, Avista, PO Box 3727, Spokane, WA 99220-3727.
□Receive written design approval from Avista Utilities.
□Get an electrical permit from government jurisdiction. Follow the National Electric Code (NEC)
as required.
□Complete the installation.
□Customer must install a separate meter base for generation production measurement by Avista
Utilities. Meter base must be Labeled “Generation Production Meter” with permanent plaquard.
(Avista will provide and install the production meter).
□Label lockable, blade type, visual open generation disconnect switch with permanent plaquard.
□Get inspections from a state electrical inspector.
After final electrical inspection approval contact Avista Utilities for production meter
installation and utility inspection. Contact phone [phone].
□Avista Utilities installs new bi-directional and generation production meters.
□Start generating power.
Load Side Taps are NOT recommended inside meter can for generation interconnections, contact
Avista Utilities for Preapproval BEFORE Installation.
Net metered generator disconnect switch must be a lockable, blade type, visual open, disconnect
switch and in the generation circuit along with the Production Meter within ten feet of the existing
Avista revenue meter and readily accessible by Avista personnel.
Figure 41- Generation Production Meter and Disconnect Switch Location
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6.2 Emergency / Standby Generation
This standard describes the minimum requirements of an electric customer served by Avista Utilities who
plans to install a power supply for his personal use during power outages and other emergencies.
Improperly installed emergency power supplies are extremely hazardous for utility workers, the public and
the customer. The customer could be held liable for substantial damages if an improperly installed,
maintained, or operated emergency power system causes any loss to any of the people involved.
In a proper installation:
1. The utility workers will not be exposed to the hazard of electrical shock during their efforts to restore
service.
2.The appliance motors of other customers will not be damaged by trying to operate
with inadequate power from a distant emergency power supply.
3. The emergency power supply itself will avoid damage from operation on a shorted
line or for too large an external load.
4. The electric meter will not be damaged.
5.The customer’s wiring will not be damaged.
Figure 42- Standby Generation
INSTRUCTIONS:
1. When in operation, the emergency power supply must be isolated from the power
utility system so it will not energize the service drop, the distribution transformer and the primary
voltage line.
AVISTA Utilities Distribution Standards DO-7.320 ESR Page 1 of 2
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2017 Electric Service Requirements 01/18/2017 Page 96
INSTRUCTIONS (continued):
a. The Customer must provide and install a ganged disconnect switch on the load side of the
electric meter. This switch must disconnect all ungrounded conductors from one power source
before connecting them to the other (Break before Make Type).
b.Failure to disconnect the emergency power supply system from the utility system may result in
substantial damages, potential injuries and liability to the customer.
2. Service entrance neutrals, ground conductors and grounds must be continuous.
3. The customer shall notify the local Avista Utilities office before and after modifying the service entrance.
Meter removal must be authorized by Avista Utilities. Wiring must comply with all state and local
electrical codes and must be approved and tagged by an authorized electrical inspector before the
meter is replaced and resealed.
4. No customer should work on or permit others to work on his own equipment unless both sources are
disconnected, properly tagged and locked out, and the circuit isadequately grounded.
5.IF THE EMERGENCY POWER SUPPLY IS TO PARALLEL AVISTA'S DISTRIBUTION SYSTEM AT
ANY TIME, CONTACT DISTRIBUTION ENGINEERING FOR PROPER COMPLIANCE BEFORE
EMERGENCY POWER SUPPLY IS OPERATIONAL.
NOTES:
1. The Customer should contact the local Avista Utilities office for additional information.
2. The Customer’s wiring must comply with all state and local electrical codes.
3. The cost of all changes to the customer service entrance, including any changes to the service drop,
are the responsibility of the Customer.
4.This standard is a duplicate of DU-6.020.
REFERENCES:
1.National Electric Code, Articles 700.5A, Article 701.5A, Article 702.5
AVISTA Utilities Distribution Standards DO-7.320 ESR Page 2 of 2
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2017 Electric Service Requirements 01/18/2017 Page 97
7.0 TEMPORARY or CONSTRUCTION SERVICE
There is an installation fee for temporary service and additional charges for correction trips.
Each new house should have one duplex outlet available when temporary power is disconnected.
Temporary single phase service from a 120/208 three phase transformer or transformer bank requires a 5
terminal meter socket.
Temporary CT Enclosures are allowed on wood posted for a period of one year.
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7.1 Temporary Overhead Service
Figure 43- Temporary Overhead Service
DIRECTIONS:
D1. These are general Avista Utilities requirements. The customer or their electrician must consult the local
electrical code authority for specific requirements. An electrical inspection permit must be
displayed before a service connection can be made.
D2. Contact the local Avista Utilities office before installation to request temporary service and to determine
available voltage and location. Whenever possible the temporary service must be located within 125
feet of the nearest pole and as near as possible to the permanent service mast location.
D3. The customer provides and installs all materials shown. Avista will install the service conductor and
meter.
NOTES:
N1. Location and height of post must allow service drop to meet service clearance in
DO-6.210.
N2. The temporary service must be overhead when the permanent service is from an overhead
transformer.
REFERENCES:
R1. Refer to Electric Service Requirements section 1.22 for available fault current at Point of Delivery.
AVISTA Utilities Distribution Standards DO-6.250 ESR Page 1 of 1
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2017 Electric Service Requirements 01/18/2017 Page 99
7.2 Temporary Underground Service
Figure 43- Temporary Underground Service
These are general Avista Utilities requirements. The customer or their electrician must consult the local
electrical code authority for specific requirements. An electrical inspection permit must be displayed
before a service connection can be made.
Contact the local Avista Utilities office before installation to request temporary service and to determine
available voltage and location. The temporary service must be located to avoid interference with existing or
future services.
The customer provides and installs all materials including the service conductor and 2” conduit. The
service conductor must be long enough to reach the source plus 5 feet and be approved by Avista.
Minimum of (3) 8 CU or (3) 6AL with white neutral. Below grade 2” conduit shall be schedule 40 PVC and
schedule 80 PVC above grade. The service conductor length must be long enough to be compliant
with the AIC rating of their service equipment. This may require extra conductor to be coiled up and
buried by the customer opposite the transformer side of the temp meter post. AIC rating and utility
max. available fault current must be noted on outside of temp meter can.
Avista installs the meter and connects the service conductor to the source:
·If the post is between 2 and 5 feet from the source, Avista will dig and backfill the ditch.
·If the post is further than 5 feet from the source, the customer will dig and backfill the ditch. Backfill
can not contain any rock larger than 4 inches. The customer is responsible for the costs required due
to additional trench length.
NOTES:
N1. If the full 3 foot burial depth cannot be met or the backfill does not support the post
adequately, then the post must be braced.
N2. The temporary service must be overhead when the permanent service is from an overhead transformer.
N3. Call before digging to locate buried utilities.
REFERENCES:
R1. Refer to Electric Service Requirements section 1.22 for available fault current at point of delivery.
AVISTA Utilities Distribution Standards DU-9.140 ESR Page 1 of 1
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8.0 SPOKANE NETWORK UNDERGROUND SERVICE POLICY
Revised Nov 19, 2013
Customers served from the Spokane Area Networked Secondary System shall meet the following minimum
requirements:
8.1. Point of Delivery
A. A premise will be served at one voltage and at one service point.
B. Avista will work with the customer to determine the service location and point of delivery based on
the capacity required to serve the customer loads. The following options will be considered by
Avista for a point of delivery:
a.Customer provides switchgear with an Avista approved dedicated utility termination
compartment and an adjoining empty pull section. The termination compartment must meet the
following criteria:
i.The switchgear bus where Avista’s cables attach will be copper and be suitable for
copper two-hole compression connectors with 1-3/4 inch hole spacing.
ii. Must meet the current Electric Utility Service Requirements Committee (EUSERC)
Specifications.
iii.Receive approval from Avista before ordering electrical equipment.
iv.Shall be located preferably against the building’s exterior wall, and must be located
no more than four feet from the building’s exterior wall.
b. Customer must provide a secondary junction enclosure located inside their building on an
exterior wall. Standard junction enclosures are:
30”x30”x18” for services up to 400 amps (Avista Network Standard DN-2.100)
40”x40”x18” for services 400 to 800 amps (Avista Network Standard DN-1.102)
48”x48”x18” for services 800 to 1200 amps (Avista Network Standard DN-2.104)
c.Avista will provide the secondary handhole if the point of delivery is located outside the building.
The standard handhole is Utility Vault 504-LA with outside dimensions of 4’-8” x 4’-8” x 4’-0
high.
C.All conductors will be copper where they contact Avista’s conductors or equipment.
a.The customer must use the least number of cables appropriate for the service size while using
cables that are 500 kcmil or smaller.
b. The customer’s electrician will provide no less than six feet of conductor length in the junction
enclosure or handhole.
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8.2. Service Voltages
A. There are two service voltages available: 208Y/120 volt and 480Y/277 volt.
B. The 3 phase load unbalance shall not exceed 10% at any time on the various phase wires
according to Washington State Electric Tariffs section 70 part 19.
C.A minimum demand of 600 kVA is required to qualify for 480Y/277 volt spot network service.
D.Customer requesting a large 208Y/120 volt service may be served from 208Y/120 volt spot
network.
E. Single-phase 120 volt loads, such as parking lot booths, traffic controllers, signs and lighting, will be
served with special permission from Avista and shall not exceed an estimated metered demand of
25 amps. Required AIC rating for these services will be determined by Avista on a case by case
basis.
208Y/120 volt Service from the Street Grid:
A. Avista will install, own and maintain all equipment located outside the building structure. The
transformer vault and equipment shall be located outside the building structure.
B.A customer construction allowance will be calculated and applied against the customer specific
electric service costs.
C.The customer equipment rating will have an Ampere Interrupting Capacity (AIC) rating of 100,000
amperes or greater. Fuses will have rejection clips so a fuse with lower AIC can not be installed.
Dedicated 480Y/277 and 208Y/120 volt Networks (spot network):
A. Customer shall be responsible for constructing the transformer vault according to Avista’s
specifications and all associated costs.
a.The vault shall be located outside the building structure.
B. With the exception of damage to or customer negligence of the vault, Avista will perform ordinary
and routine vault maintenance and repairs. This includes maintenance, repair, and replacement of
vault equipment and electrical fixtures (Avista policy adaptation January, 1, 2013).
C.Avista will be responsible for cleaning the vault, replacing vault lights and removing storm water.
D. A customer construction allowance will be calculated and applied against the customer specific
electric service costs.
E. Avista will provide the customer with a minimum Ampere Interrupting Capacity (AIC).
8.3 Enclosures and Conduit Runs
A. Avista shall be responsible for the costs associated with the service installation in the public right of
way including:
a. A specified number of four inch Schedule 40 PVC conduits and cable to the customer’s point of
delivery.
b.Replacing the section of sidewalk or pavement required to install the service if not otherwise
being removed.
B.The customer shall be responsible for the following work on their property:
a. The cost of excavation, installing a specified number of four inch Schedule 40 PVC conduits,
conduit spacers, concrete encasement, backfill and compaction.
b. Installing four inch Schedule 80 conduit where the conduit is exposed inside the building.
c. Providing the exterior building wall penetration according to Avista requirements.
C.The customer shall be responsible for the cost of excavation, backfill, conduit and cables for:
Staff_PR_094 Attachment A Page 102 of 110
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a. Temporary services if the temporary service location is different than the permanent service
location.
b. Facilities with no permanent building foundations. (i.e.: pay booths, signs, customer owned
parking lot lighting, etc.)
D.All enclosures provided by the customer shall be sealable and approved by Avista.
E.Avista will utilize existing service conduits when feasible.
8.4 Easements
A. Avista may require an easement for conduits and cables on customer property. These easements
will be granted to Avista at no cost.
8.5 Metering
A. Avista’s meter department must approve metering equipment before ordering. Contact Avista’s
meter department at 509-495-4648 for all metering requirements.
B. Metering equipment will be located on the source side of the main disconnect.
C.Each individual single phase tenant meter position shall be field phase-able so the 3 phase service
is balanced.
D. All 1st floor spaces shall have manual circuit closing sockets.
8.6 Generation
A. Closed transition transfer switch (make before break) is not permitted in the downtown network for
switching customer’s standby or emergency generator.
B. Any interconnection of a customer owned generation facility to the network requires review, studies
as necessary and written approval by Avista.
8.7 Other Items
A. The customer’s technical representative or electrician must provide Avista with final load
calculations, square footage per floor and how each floor will be utilized before equipment is
ordered.
B.The customer’s technical representative or electrician will be responsible for verifying proper phase
rotation after a service modification.
C.Avista shall make the final determination whether a customer(s) qualifies for network service or
whether network service is available at the customer location.
D. When a new service is installed to replace an existing service to a building, the existing
service shall be de-energized as soon as possible (within three days) from the date of
commission.
E. Structures (i.e. awnings, building protrusions, etc.) that are located in a manner that
interferes with Avista’s ability to access and maintain its facilities in a vault or manhole,
shall be removed, relocated, or replaced at the customer’s expense. Any such structure to
be located near (including air space above) Avista’s facilities shall be discussed with Avista
Network personnel prior to installation. .
F. Avista retains the right to modify this policy without notice to meet national, state, and local
jurisdiction electrical and structural codes and regulations and to promote worker,
customer, and public safety.
Staff_PR_094 Attachment A Page 103 of 110
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9.0 ELECTRICAL FORMULAS & COMMON TERMS
To Find Direct
Current
Alternating Current
1Ø 2Ø – 4 Wire* 3Ø
Amperes
from
horsepower
746
%
746
%
746
2 %
746
1.73 %
Amperes
from kilowatts
1000

1000
2
1000
1.73
Amperes
from kva
1000
1000
2
1000
1.73
kilowatts
1000

1000
2
1000
1.73
1000
kva
1000
2
1000
1.73
1000
Horsepower
(output)
%
746
%
746
2 %
746
1.73 %
746
Power factor 1000

1000
2
1000
1.73
*For 3W, 2Ø circuits the current in the common conductor is 1.41 times that in either of the other conductors.
Common electrical terms
Ampere I = Unit of current or rate of
electricity flow
Watthour or
Kilowatt hour
Whr = unit of electrical work or
kWhr = 1000 whrs
Volt E = Unit of voltage or potential
difference between two points.
Similar to pressure.
Horsepower Hp = measure of the rate work is
performed
Equivalent to;
746 watts or
raising 33,000 lbs, one ft, in
one minute
OHM R = Unit of resistance to electrical
flow
Demand
factor
The ratio of maximum demand of
a system to the total connected
load.
Volt amperes
or
Kilovolt
ampere
Va = unit of apparent power or
kVa = 1000 volt amperes
Diversity
factor
The ratio of the sum of individual
maximum demands of the various
parts of a system to the maximum
demand of the whole system
Watt or
Kilowatt
W = unit of real power
kW = 1000 watts
Load factor The ratio of the average load over
a designated period of time to the
peak load occurring in that period.
Power factor Pf = ratio of real to apparent
power
Table 8- Electrical Formulas and Common Terms
Staff_PR_094 Attachment A Page 104 of 110
2017 Electric Service Requirements 01/18/2017 Page 104
CALL BEFORE YOU DIG
CALL 2 DAYS BEFORE YOU DIG
NATIONAL # 811
LOCAL AREA NUMBERS
SPOKANE _______________________________ 1-800-424-5555
PULLMAN-MOSCOW ______________________ 1-800-424-5555
LEWISTON ______________________________ 1-800-324-1585
CLARKSTON-800-5534344
COEUR D’ALENE AREAS:
BENEWAH – SHOSHONE CO _______________ 1-800-398-3285
BONNER – BOUNDARY CO ________________ 1-800-626-4950
KOOTENAI CO ___________________________ 1-800-428-4950
Staff_PR_094 Attachment A Page 105 of 110

2017 Electric Service Requirements 01/18/2017 Page 105

APPENDIX A – List of Figures

Figure 1- New Underground or Overhead Electric Service ........................................................... 13 
Figure 2 - New Underground Service .............................................................................................. 13 
Figure 3- New Overhead Service ..................................................................................................... 14 
Figure 4 - Cable Phase Rotation Marking ....................................................................................... 15 
Figure 5 - Electric Conduit Sweep Specifications .......................................................................... 20 
Figure 6- Location of Sweeps on Avista Poles ............................................................................... 21 
Figure 7- Residential Gas and electric Meter Clearances.............................................................. 22 
Figure 8- Flood Zone Meter Enclosure Installation ........................................................................ 24 
Figure 9- Roof Cricket ...................................................................................................................... 28 
Figure 10- Overhead House Mast .................................................................................................... 29 
Figure 11- Overhead to Overhead Service Pole ............................................................................. 31 
Figure 12- Overhead to Underground Service Pole ....................................................................... 33 
Figure 13- Overhead Service Clearances at Building .................................................................... 35 
Figure 14- Clearances to Buildings and Appurtenances ............................................................... 37 
Figure 15- Overhead Service Clearances over Ground and Buildings ........................................ 40 
Figure 16- Clearances Around Swimming Pools and Hot Tubs .................................................... 42 
Figure 17- Service Ditch Detail ........................................................................................................ 45 
Figure 18- Clearance to Transformers ............................................................................................ 47 
Figure 19- Clearances to Other Equipment Buildings and Swimming Pools .............................. 49 
Figure 20- Residential Underground Exterior Service ................................................................... 51 
Figure 21- Residential Underground Exterior Service 2 ................................................................ 52 
Figure 22- Direct Buried Underground Service Pedestal .............................................................. 54 
Figure 23- Post Type Meter Pedestal .............................................................................................. 56 
Figure 24- Bollard Clearances ......................................................................................................... 62 
Figure 25- Bollard Construction ...................................................................................................... 63 
Figure 26- Three Phase Transformer Concrete Pads .................................................................... 66 
Figure 27- Pedestal Mounted Meter Enclosure for Dedicated Transformer ................................. 68 
Figure 28- Secondary Enclosure Fiberglass Box Pad ................................................................... 69 
Figure 29- Secondary Enclosure Poured In Place Concrete Pad ................................................. 70 
Figure 30- Padmounted Secondary Enclosure ............................................................................... 72 
Figure 31- Conduit Entrance Single-Phase Transformer ............................................................... 75 
Figure 32- Conduit Entrance 1 & 2 Phase Padmounted Junction Enclosures ............................ 76 
Figure 33- Conduit Entrance 3-Phase Padmounted Junction Enclosures ................................... 77 
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Figure 34 - Self-Contained In-Line Meter Socket Diagrams .......................................................... 83 
Figure 35- Pulling/Termination Enclosure Utility Space ................................................................ 85 
Figure 36- Typical Switchboard Multi-Meter Layout ...................................................................... 87 
Figure 37- 1 Phase Current Transformer Metering 401 to 800 Amps ........................................... 88 
Figure 38- 3 Phase Current Transformer Metering 201 to 800 Amps ........................................... 89 
Figure 39- Cell Tower Metering ........................................................................................................ 90 
Figure 40- Service Voltages ............................................................................................................. 91 
Figure 41- Generation Production Meter and Disconnect Switch Location ................................. 94 
Figure 42- Standby Generation ........................................................................................................ 95 
Figure 43- Temporary Overhead Service ........................................................................................ 98 

Staff_PR_094 Attachment A Page 107 of 110

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APPENDIX B – List of Tables

Table 1- Point of Delivery Available Fault Current ......................................................................... 23 
Table 2- Clearances to buildings and Appurtenances ................................................................... 38 
Table 3- Clearances Around Swimming Pools and Hot Tubs ....................................................... 42 
Table 4- Required Distance between Underground Distribution Equipment and Propane
Facilities............................................................................................................................................. 50 
Table 5- Three Phase Transformer Concrete Pad Dimensions ..................................................... 67 
Table 6- Conduits and Conductors From Transformer to Secondary Enclosure ........................ 73 
Table 7- Self-Contained Socket Required Metering Equipment .................................................... 81 
Table 8- Electrical Formulas and Common Terms ....................................................................... 103 

Staff_PR_094 Attachment A Page 108 of 110

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INDEX
Avista Utilities
contacts, 9
representative, 11, 12, 14, 18, 60
Bollards, 51, 62, 63
Bypasses
horn style, 83
slide type, 83
Conduit, 15, 19, 20, 21, 22, 27, 29, 30, 45, 54,
55, 61, 73, 75, 77, 79, 80, 82, 87, 90, 103
pull strings, 20
swedge couplings, 20, 21
type, 20
Customer Account
flat rate, 14
Customer Generation, 97
emergency, 99
net-metered, 98
Customer Responsibility
costs, 18, 19, 82, 97, 103
equipment, 11
expense, 18, 81, 96
obstructions, 8, 20, 87
payment, 11, 27
Ditch, 27, 45, 61, 103
backfill, 19, 27, 45, 55, 103
excavators, 45
joint ditch, 18
Electric Vehicles, 18
Electrical Permit, 10, 52, 55, 75, 94, 100, 103
inspection sticker, 10
Equipment
air conditioners, 18
chubs, 29
ct enclosure, 59, 87
current transformer, 45, 60, 87
electric space heating, 18
electric tankless water heating systems, 18
ground rod, 61, 73, 75, 76
handhole, 13, 19, 45, 51, 67
house knobs, 29
junction enclosure, 51, 76, 79, 80
large motors, 18
lugs, 45, 60, 61, 75, 76, 89, 92, 93, 94
luminaries, 19
mast head. See weatherhead
masts, 28, 29, 60
multiple masts, 29, 60
pedestals, 51, 56
power conditioning devices, 18
pulling enclosure, 11
pulling/termination enclosure, 11, 62, 82
raceway, 15
roof cricket, 28, 29
secondary enclosure, 61, 69, 73, 75, 76
sweep, 19, 20, 45, 55, 87
switch gear, 11
switchboard, 11, 45, 62
transformer, 11, 18, 19, 20, 24, 27, 45, 51,
59, 60, 61, 62, 69, 73, 75, 76, 84, 87, 91,
92, 93, 96, 99, 101, 103
weatherhead, 16, 27, 28, 59
Excavation
call before you dig, 7
Facility
anchor point, 29, 30, 60
apartment, 27, 83
balcony, 37, 40
buildings, 11, 12, 38, 41, 50
carports, 12
commercial building, 59, 61
commercial definition, 59
drain fields, 12
eave, 56
federal buildings, 10
fence, 12
flood zones, 25
fuel tanks, 12
future buildings, 12
gable, 28, 54
garage, 54
hot tubs, 43
individual tenant spaces, 11
irrigation, 83
joint use, 51
ladder, 37, 40
landscaping, 18
large commercial multi-story buildings, 12
mobile homes, 6, 27
multiple buildings, 12
patios, 12
porches, 12
residential, 11, 13, 19, 20, 23, 27, 52, 53, 60,
84
roadway crossings, 19
Staff_PR_094 Attachment A Page 109 of 110

2017 Electric Service Requirements 01/18/2017 Page 109

septic systems, 12
slab, 11, 82
stairway, 37, 40
sub-divided, 12
swimming pools, 43, 50, 51
vehicular traffic, 81
wall, 11, 12, 28, 60, 62, 76, 82, 83
window, 37, 40, 61, 69, 73
Fault Current, 24, 104
Gas, 23, 51
Labels, 82
Lifting Handles, 83
lifting handles, 89
Lock, 82, 94
Metering Equipment, 11, 81
MCC Sockets, 83, 84
meter locking device, 10
meter seals, 19
meter socket, 19, 54, 81, 82, 83
self contained sockets, 84
National Electrical Code, 10, 12, 16, 17, 24, 37,
51, 82
Point of Delivery, 11, 12, 18, 28, 59, 60, 76, 88,
96, 104
definition, 11
Project Phase
early planning, 11
Public Utility Commission, 10
Service
accessibility, 12
agreement, 11, 27
altered, 13
capacity requirements, 12
clearances, 23, 30, 36, 38, 39, 40, 41, 43,
50, 51, 63, 73
delta - high leg, 15, 16, 84
delta 3-wire 3 phase, 17
delta four wire, 15
disconnection, 11, 15, 18, 45, 62, 81, 98,
100
fault current, 17, 24
location, 10, 13, 31
major changes, i, 17
multiple services, 12
phase designation, 15
phase rotation, 15, 16, 17
phases, 14, 15, 96
reconnection, 10
residential service definition, 27
service pole, 32, 34
service voltage, 14, 15, 96
single point of service, 12
sprinkler, 83
temporary, 101, 103
underground service, 11, 12, 17, 60
work space, 81
wye service, 19
Trees, 10, 18
Voltage Drop, 12
Voltage Flicker, 19
Voltage Unbalance, 96

Staff_PR_094 Attachment A Page 110 of 110