20230505122 Supplemental Attachment B.pdf

Distribution Feeder Management Plan (DFMP) – System-Wide Programs - Design Criteria Manual 1
DFMP
Distribution Feeder
Management Plan
Structure-Specific Programs
Design Criteria Manual
Staff_PR_122 Supplemental Attachment B Page 1 of 37

Distribution Feeder Management Plan (DFMP) – Structure-Specific Programs - Design Criteria Manual
(Applicable to Transformer Change Out Program (TCOP) and Wood Pole Management (WPM)) 2

Table of Contents

TABLE OF FIGURES .....................................................................................................................3
INTRODUCTION ...........................................................................................................................4
ARRESTERS ...................................................................................................................................5
AVIAN/RAPTOR PROTECTION ..................................................................................................8
CROSS ARMS.................................................................................................................................9
CUTOUTS .....................................................................................................................................11
FUSING .........................................................................................................................................13
GROUNDS ....................................................................................................................................14
GUYING ........................................................................................................................................15
INSULATORS ...............................................................................................................................17
OVERHEAD CONDUCTOR ........................................................................................................20
OPEN WIRE SECONDARY ........................................................................................................22
STREET AND AREA LIGHTS ....................................................................................................23
TRANSFORMERS ........................................................................................................................26
UNDERGROUND .........................................................................................................................29
WOOD POLES ..............................................................................................................................31
REDUCED SCOPE .......................................................................................................................35
VERSION HISTORY ....................................................................................................................36

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Table of Figures

FIGURE 1: EXAMPLE OF OLDER ARRESTER WITH AIR GAP. EARLY EXPULSION ARRESTER BY JOSLYN
SUPPLY CO. 1940 VINTAGE ..................................................................................................... 6
FIGURE 2: CHANCE BRAND PORCELAIN ......................................................................................... 12
FIGURE 3: PORCELAIN BOX ............................................................................................................ 12
FIGURE 4: OPEN LINK .................................................................................................................... 12
FIGURE 5: Q-Q ............................................................................................................................... 12
FIGURE 6: LOAD BREAK (ELEPHANT EAR) ..................................................................................... 12
FIGURE 7: V-SHAPED, GE DURA-BUTE BUTYL WITH CAST IRON TOP AND BOTTOM .................... 12
FIGURE 8: DAMAGED INSULATOR .................................................................................................. 18
FIGURE 9: DAMAGED INSULATOR .................................................................................................. 18
FIGURE 10: POLE WITH CHARRING AT CROSS ARMS INDICATING 34.5 KV EPOXILATOR DEAD END
INSULATOR DETERIORATION ................................................................................................. 19
FIGURE 11: SINGLE LED ON STREET LIGHT POLE 100W-TYPE CODE 431L 200W-TYPE CODE
531L ...................................................................................................................................... 23
FIGURE 12: SINGLE LED ON LINE POLE 100W-TYPE CODE 435L 200W-TYPE CODE 535L .......... 23
FIGURE 13: DOUBLE LED ON STREET LIGHT POLE 100W-TYPE CODE 441L 200W-TYPE CODE
541L ...................................................................................................................................... 23
FIGURE 14: 100W EQUIVALENT-TYPE 3 ......................................................................................... 24
FIGURE 15: 200W EQUIVALENT-TYPE 3 ......................................................................................... 24
FIGURE 16: 100W EQUIVALENT-TYPE 5 ......................................................................................... 24
FIGURE 17: 200W EQUIVALENT-TYPE 5 ......................................................................................... 24
FIGURE 18: PIPE CLAMPS ON EXISTING MAST ARMS TO BOND THE MAST ARM TO SYSTEM NEUTRAL25
FIGURE 19: NEW ALUMINUM MAST ARMS AND GROUND/BOND PER AVISTA STANDARDS ............... 25

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Distribution Feeder Management Plan (DFMP) – Structure-Specific Programs - Design Criteria Manual
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INTRODUCTION

The Designer shall perform and document the design result from the following in accordance
with the DFMP – Structure-Specific Programs - Process Manual.

Design, install, replace, and maintain all arresters in accordance with the National Electric Safety
Code (NESC), Avista’s Distribution Standards, and Avista’s Existing Facilities Replacement
Modification Guidelines document.

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Distribution Feeder Management Plan (DFMP) – Structure-Specific Programs - Design Criteria Manual
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ARRESTERS

 Overhead1
o Design arresters on all overhead transformers to be replaced or if replacing the
cutout.2
o Design arresters on each phase of the end of line dead-end structures unless there is a
transformer located within a few spans to conform to Avista’s Distribution
Standards.3 4
o Design a fiberglass standoff bracket for an arrester on single phase overhead
construction when no equipment cross arm is available to conform to Avista’s
Distribution Standards.5

1 Question: Should # 4 copper that is used on existing lightning arresters be changed out for braided wire that
creates a visible indication of when a lightning arrester blows? #6 apparently works for this too. Apparently an
outage is not needed to change out the #4 wire on a lightning arrester. Is this within scope? (Spokane General
Foreman Meeting, Fall, 2014) Answer: No need to change out the #4 on an existing lightning arrester. (Mark Weiss,
Jan. 2015)
2 Reference: DO-1.007, 4.146, 4.425
3 Question: Where should a lightning arrester be placed when located at a double dead end and a 3 phase end off an
intersection? (Spokane General Foreman Meeting, Fall, 2014) Answer: Only need to add on one location, not on
both, unless arresters are installed nearby. (Mark Weiss, Jan. 2015)
4 Reference: DO-1.007, 4.425
5 Reference: DO-1.007, 2.318, 4.146
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 Underground
o Design arresters at each riser pole location to conform to Avista’s Distribution
Standards.6

 Other
o Check, as well as possible from the ground, the required clearances from the arrester.
7 8
o Replace cracked or blown porcelain arresters and butyl rubber arresters with signs of
chalking.
o Replace older style arresters that have an external air gap.

Figure 1: Example of older arrester with air gap. Early expulsion arrester by Joslyn Supply Co. 1940 Vintage

6 Reference: DO-4.425 and DO-1.140
7 Question: May arresters be installed above the arm and below the arm—are both acceptable? (Spokane General
Foreman Meeting, Fall, 2014) Answer: Yes, arresters may be framed either way provided current standards are met.
(Mark Weiss, Jan. 2015)
8 Reference: DO-2.113, DO-3.324, DO-2.110
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o Only reframe arresters that are currently framed above the cross arm to below the
cross arm if the arrester is “Identified For Replacement”.9
o Design arrester wildlife protectors on all new overheard transformers.10
o Add bushing caps as required.
o Add arresters to protect poles with Air Switches. Mark Weiss to review.
o Arresters shall be installed at the same level (all arm-mounted or all tank-mounted.)
o For double dead-end poles with no jumpers, locate one set of arresters on an adjacent
pole if there are no arresters within a few spans. (Trying to avoid 6 arresters on a
double dead-end pole.)

 Compare the cost of the “Identified For Replacement” components versus the cost of
replacing the entire pole using the “Component Versus Pole Replacement Analysis Tool” to
determine what should be replaced.11

9 Question: Are the outages associated with squirrels that could result from arrester(s) being framed above the cross
arm large enough to support reframing the arrester(s) below the cross arm? (Mark Weiss, DFMP Review Meeting)
Answer: No, because Squirrel outages = 262, Total sustained outages = 7,589, squirrel outages as a percentage of
overall outages = 3.45% (Reliability Data from Amber Fowler to Reuben Arts, 2014)
10 Reference: DO-4.176
11 Reference: DO-1.005
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Distribution Feeder Management Plan (DFMP) – Structure-Specific Programs - Design Criteria Manual
(Applicable to Transformer Change Out Program (TCOP) and Wood Pole Management (WPM)) 8

AVIAN / RAPTOR PROTECTION

 Design appropriate avian protection using:
o Cutout covers13
o Insulator pin and conductor covers14
o Primary Connection Protection15

 Replace double-deadend, wood cross arms with the appropriate fiberglass cross arm if
raptor nests are a known problem in the area. Alternatives are:
o Perch Nesting Deterrents16
o Cross Arm Bird Cover17

12 Reference: DO-2.801 and 2.802
13 Reference: DO-2.810
14 Reference: DO-2.820
15 Reference: DO-2.826
16 Reference: DO-2.864
17 Reference: DO-2.860
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Distribution Feeder Management Plan (DFMP) – Structure-Specific Programs - Design Criteria Manual
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CROSS ARMS

 Determine which cross arms to replace with fiberglass arms. This analysis includes
considerations in regards to condition, length, balanced loading, leaning, attached equipment
and materials, etc.18

 Replace all primary wood cross arms with the appropriate fiberglass cross arm if any of the
following apply:19
o Cross arms are split and cannot be repaired with a split bolt.
o Contains wood pins that are floating sinking, split or the pin is leaning in the hole.
o Cross arms that don’t contain the appropriate angle pins.20

 Replace double-deadend, wood cross arms with the appropriate fiberglass cross arm if either
of the following apply:
o The arms and insulators are NOT in good operating condition.
o Raptor nests are a known problem in the area.21

 If an equipment arm is identified for replacement, relocate the attached hardware to the
primary cross arm.

 Cross arms will always be replaced if the pole is being replaced.

18 Cross arm replacement is condition-based (not brand, type, etc.) (Rodney Pickett, DFMP Weekly Review
Meeting, 1-14-15)
19 The first steel pin specification was created in 1987. Wood pin hole adapters may have been used in the interim
and a plastic version was brought in the 2006 timeframe. Distribution Engineering deleted the hole adapters in 2012,
which allowed a steel pin to be installed in a wood pin cross arm. Without the adapters, requires changing the arm
out if it previously had wood pins (or using salvaged wood pins). (Mark Weiss, DFMP Weekly Review Meeting, 5-
13-15)
20 Reference: DO-2.407
21 Reference: DO-2.8
22 Reference: AFM Layer – “Avian Protection Zone”
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 Compare the cost of the “Identified For Replacement” components versus the cost of
replacing the entire pole using the “Component Versus Pole Replacement Analysis Tool” to
determine what should be replaced.23

23 Reference: DO-1.005
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CUTOUTS

 If the pole, cross arm or transformer is being replaced, the porcelain cutout shall also be
replaced.

 Replace cracked porcelain cutouts and butyl rubber cutouts with signs of chalking.

 Do not replace cutouts based only on age.

 Design Fuse Marking Signs on all poles with a line cutout that are “Identified for
Replacement” by sending the pole number and a map to the Regional Operations
Engineer.24

 If cutout(s) located on an equipment arm are identified for replacement, relocate the
cutouts to the primary cross arm.

 If replacing a cutout on an existing single phase pole with an “Identified for
Replacement” crossarm with the neutral in the low position and there are no obstructions:
o Install a fiberglass standoff bracket for a cutout on single phase armless overhead
construction.25

 Replace the following types of cutouts:
o Chance brand porcelain
o Porcelain Box
o Grasshopper
o Open Link
o Q-Q

24 Reference: DO-4.410
25 Reference: s DO-1.007, DO-2.318, and DO-4.146
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o Load Break (elephant ear)
o V-shaped, GE Dura-Bute butyl with cast iron top and bottom

Figure 2: Chance Brand
Porcelain

Figure 3: Porcelain Box

Figure 4: Open Link

Figure 5: Q-Q

Figure 6: Load Break
(Elephant Ear)

Figure 7: V-Shaped, GE
Dura-Bute Butyl with
Cast Iron Top and
Bottom

 Compare the cost of the “Identified For Replacement” components versus the cost of
replacing the entire pole using the “Component Versus Pole Replacement Analysis Tool”
to determine what should be replaced.26

26 Reference: DO-1.005
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FUSING

 General
o Install a new fuse of the correct size when replacing and installing a new pole, cross
arm, or cutouts.
o Consult the Regional Operations Engineer to provide the following:
 Recommendations for fusing a specific line cutout “Identified for
Replacement”.

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Distribution Feeder Management Plan (DFMP) – Structure-Specific Programs - Design Criteria Manual
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GROUNDS

 Design pole grounds and ground rods at each new installed primary pole location.27

 Design ground wire and ground rods on all poles with primary devices and equipment.28

 Identify and replace pole grounds in the following situations:
o Cut or damaged pole grounds, or

 Identify and report to Joint Use Administrator all independent (foreign-owned) grounds that
are on the same pole as an Avista pole ground.29

 Compare the cost of the “Identified For Replacement” components versus the cost of
replacing the entire pole using the “Component Versus Pole Replacement Analysis Tool” to
determine what should be replaced.30

27 Reference: DO-3.510, DO-3.512
28 Reference: DO-3.500
29 Reference: DO-1.419
30 Reference: DO-1.005
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Distribution Feeder Management Plan (DFMP) – Structure-Specific Programs - Design Criteria Manual
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GUYING

 Evaluate and ensure all (primary, neutral, secondary districts and Joint Use positions)
new, or to be replaced guy wires and anchors are sized to conform with Avista’s
Distribution Standards.31

 Existing anchors may be re-used if in good condition. Replace anchors if any of the
following apply when replacing the pole or as identified during the Predesign:
o The eye nut is damaged
o The anchor rod is bent
o The anchor rod is rusted or severely pitted
o The anchor has pulled out of the ground more than two inches
o There are anchors closer than three feet apart
o More attachments to the anchor/eye than the eye is rated to hold
o The anchor eye is buried beneath the ground line
o The Height to Length ratio of the guy is insufficient Standard Reference
o The anchor rod is exposed more than the maximum allowable exposure for each
type of installation

 Existing guy wires may be re-used if in good condition. Evaluate slacked guy wires to
determine cause and evaluate for corrective action. Replace guy wires if any of the
following apply:
o The guy wires are frayed
o The guy wires have broken strands
o The guy wires are bent
o The insulator is broken, damaged, or not intact

31 Guying requirements have been basically the same for the last 50 years, so guying must meet current standards
and is not grandfathered. (M. Weiss, DFMP Review Team Meeting, 7-1-15)
32 Reference: Avista Distribution Engineering – “Avista Existing Facilities Replacement Modification Guidelines”
33 Reference: DO-2.520, DO-2.507, and DO-2.564
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 Install guy markers on all Avista guy wires.

 Notify Joint Use if Joint Use facilities are missing down guys, guy markers, or anchors.

 Review and design guy fiber rope insulators in all new guy wire installations and on
poles where Joint Use and/or all types of secondary are present.34

 Use a bollard or fiberglass crossarm in pastures.
o Do not use pole butts or timbers in farmers’ fields to protect guying.

 Guying and anchoring into buildings or structures should be replaced with standard
guying if the pole is being replaced, unless reviewed by engineering.

 Consider alternatives to replacing existing anchors and guy wires at locations of limited
space:
o Span guying or slack spans are acceptable alternatives to changing existing
guying or anchoring.35
o Alternative may be to use a partial self supporting structures or partial self
supporting structures guyed in only full tension direction36

 Evaluate the cost effectiveness of the identified for replacement components versus the
cost effectiveness of replacing the pole using “Component Versus Pole Replacement
Analysis Tool”.

34 Reference: DO-2.502
35 DO-2.392, DO-2.555-2.560
36 (DE buck DE). (DO-2.392)
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INSULATORS

 Avista’s current standard is the vise top plastic pin insulators on wood and fiberglass
cross arms.37

 Use 8kV vise top pin insulators for neutral on cross arm at all voltages.38

 Avista’s current standard DE insulator is polymer insulators on pole deadends, wood and
fiberglass deadend arms.39

 Avista’s current standard DE neutral insulator is 8kV glass insulators for pole deadends,
wood or fiberglass deadend arms.40

 Design a neutral deadend insulator to replace existing spools on AAC and ACSR
conductors only when the pole is “Identified for Replacement”.41 42

 Only use deadend insulators underneath the cross arm on old construction slack spans.
All new construction slack/full spans should adhere to the current standard.43

 Install a One-Rack and a Three-Rack for transformers when pole is “Identified for
Replacement” in urban areas.

 Call out when the conductor needs to be installed under the ear of the insulator at angles
requiring this construction.

37 Reference: DO-1.007
38 Reference: DO-2.460
39 Reference: DO-2.440
40 Reference: DO-2.435
41 There is no specific NESC requirement to insulate the neutral; however, it is common practice to install
insulators. (M. Weiss, DFMP Review Team Meeting, 4-29-15)
42 Reference: DO-2.109
43 Reference: DO-2.116
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 One racks that are bent shall not be “Identified for Replacement”.

 2x2 washers used at the location where the neutral is attached at the pole shall only be
replaced when doing other work on the pole and the neutral is 2/0 ACSR or larger.

 If other work is required on a pole that has a slack span with auto dead-ends, then call out
to replace the auto dead-ends with the appropriate connectors.

 Replace any insulators that show signs of damage (chips), tracking, or deterioration
(chalking).

Figure 8: Damaged Insulator Figure 9: Damaged Insulator

 Replace all non-vice top existing insulators as part of a cross arm replacement.44

 Vertical clamp top insulators can be used for uplift construction up to 10 degrees.
Vertical angles greater than 10 degrees should use deadend-deadend construction
o DO-2.397

 Replace 34.5 kV Epoxilator dead end insulators that show signs of damage (chips),
tracking, or deterioration (chalking).

44 Another reason to not reuse non-vice top insulators is that there are no new ties available and preformed ties
cannot be reused. (D. Labau, DFMP Review Team Meeting, 3-18-15)
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Figure 10: Pole with Charring at Cross Arms Indicating 34.5 kV Epoxilator Dead End Insulator Deterioration

 Evaluate the cost effectiveness of the identified for replacement components versus the
cost effectiveness of replacing the pole using “Component Versus Pole Replacement
Analysis Tool”.

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OVERHEAD CONDUCTOR

 Review all vertical and horizontal clearance requirements when a pole is replaced.45

 Repair overhead conductor that has frayed.

 Repair overhead conductor whose sag blatantly violates clearance requirements, or install
poles of the appropriate height to conform with Avista’s Distribution Standards.46

 Hot Line Clamps47
o Use aluminum hot line clamps on aluminum conductors only.48
o Use copper hot line clamps on copper and steel conductors only.48
o Hot line clamps are not to be used to connect main lines or heavily loaded
laterals49
o Hot line clamps may be used when connecting taps of conductor sizes 1/0 copper
and smaller. Use ampacts on all jumpers 2/0 ACSR and larger.50

 Slack Spans
o Remove all automatic deadends and sleeves in slack spans if working in the
supply space.51
o Slack spans should only be used when typical guying cannot be utilized.52

45 Reference: DO-1.407 and DO-3.302 to DO-3.374
46 Reference: DO-3.314 and DO-6.210
47 Many bi-metallic hot taps were purchased that are used on copper conductors, but the tin material wears through
and creates a conductor hot spot (burn downs). (Mark Weiss, DFMP Weekly Review Meeting, 5-13-15)
48 Reference: DO-3.465
49 Reference: DO-3.442
50 Reference: DO-3.465
51 Reference: DO-2.116
52 Reference: DO-2.116 and DO-2.392
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 Considerations should be given for the height, class, and setting depth of a pole based on
soil conditions. Contact Distribution Engineering with any design related questions on
slack spans.

 When moving conductor on a pole in the supply space, first investigate if the adjacent
poles are red tagged so that pole change-outs occur first.

 Replace only one span of two wire open wire secondary districts when replacing a street
light pole. Do not replace the entire district.

 Customer-Owned Meter Poles
o Do not use customer-owned meter poles to support secondary conductor that
continue on to serve additional customers.

 Vegetation Management
o Designers shall consult vegetation management when applicable for all overhead
construction.

 Roof Horses53
o Do not install new roof horses.
o If service is being performed on the service or primary, mitigate the roof horse.
 This may involve installing a new service pole or relocating the service
connection to the secondary.54

 Evaluate the cost effectiveness of the identified for replacement components versus the
cost effectiveness of replacing the pole using “Component Versus Pole Replacement
Analysis Tool”.

53 It references having to horse the service over the roof to a meter. They also actually observed where someone
nailed a saw horse to their roof hence Saw horse/ Roof Horse.
54 NESC 217B
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OPEN WIRE SECONDARY

 Consult the Program Administrator about the options to modify the horizontal open wire
secondary districts that require extensive repair work.

 Services should be reviewed for meeting clearance requirements. Services clearly not
meeting clearance requirements shall be addressed. All services needing immediate
attention or difficult to remedy situations shall be input into Maximo for the local office
to address.

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STREET AND AREA LIGHTS

 Replace street and area light fixtures with the appropriate LED fixture on poles that are to
be replaced. The LED Change-Out Program will replace fixtures on poles that are not
being replaced.
o Ensure street light fixture replacement uses the correct type code call out.

Figure 11: Single LED on Street
Light Pole 100W-Type Code 431L
200W-Type Code 531L
Figure 12: Single LED on Line
Pole 100W-Type Code 435L 200W-
Type Code 535L
Figure 13: Double LED on Street
Light Pole 100W-Type Code 441L
200W-Type Code 541L

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 Install the LED fixture with the correct distribution light type55

 Type 3 – Install Mid Block

Figure 14: 100W equivalent-Type 3 Figure 15: 200W equivalent-Type 3

 Type 5 – Install at Intersections

Figure 16: 100W equivalent-Type 5 Figure 17: 200W equivalent-Type 5

55 Reference: DO-5.215 and DU-8.215
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 LED lighting needs bonding to the neutral for overhead. Bonding is going to be critical
for the AMI project using antenna attachments to the street light.
o Install pipe clamps on existing mast arms to bond the mast arm to system
neutral56

 Install the new aluminum mast arms and ground/bond per Avista standards

 New aluminum mast arm lengths are 4ft, 8ft and 12ft. The 2ft aluminum mast arms are
for communication57

Figure 19: new aluminum mast arms and ground/bond per Avista standards

56 Reference: Spec 5100.100
57 Reference: DO-5.310 and DO-5.335
Figure 18: pipe clamps
on existing mast arms to
bond the mast arm to
system neutral

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TRANSFORMERS

 Transformer Sizing
o Calculate the correct size of all overhead transformers that are “Identified for
Replacement”.58 59
o If the transformer is undersized, replace with the correctly sized transformer.
o If the transformer is oversized use the Oversized Transformer Cost Comparison
Tool.

 Identified For Replacement Transformers
o Replace all overhead transformers identified as having oil leaks.
o Replace all Pre-1981 overhead transformers if the pole is being replaced.
o Replace the entire bank if two or more transformers in a bank are “Identified For
Replacement” (transformer sizing, oil leaks or Pre-1981). Replace only the
transformer “Identified For Replacement” if only one of the transformers in a
bank is “Identified For Replacement”.
o Re-install 1981 and newer transformers on poles being changed out, unless the
transformer(s) is “Identified For Replacement”.60

 Design transformer and arrester wildlife protectors on all new overheard transformers.61

 Use the guard on 13, 24 and 34.5 kV transformers or capacitor bushings that are
“Identified for Replacement” or if other work is required on the pole.

 Idle or Unused Transformers

58 Reference: DO-4.137, DO-4.105, DU-5.002, DU-5.006
59 Reference: Avista’s Residential Design Workbook on AVAnet (Transformer Sizing Tool, Flicker Tool, and
Voltage Drop Tool
60 Reference: DU-4.206, DU-4.222, DU-4.230, DU-5.020
61 Reference: DO-4.176
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o Remove idle or unused transformers. Verification with the Avista local
construction office is required before removal.
o Metered transformers require customer approval for removal.

 Riser Wire and Connectors
o When replacing a transformer with weatherproof riser wire, replace the riser wire
and connectors.

 Application of Seed-Based Oil Filled Transformers
o Transformers located within 20 feet of a school building shall filled or retro-filled
with FR-3 transformer oil. FR-3 oil reduces fire risk.
o Review and consider moving overhead facilities to underground if appropriate as
it reduces the overall risk. Entrances, exits, and general location (limited exit
points) should be considered in the overall review.62

 Smart Transformers
o Leave smart transformers in-service if they are properly sized and not damaged or
leaking.
o Remove undersized in-service smart transformers and replace with appropriately
sized traditional non-smart transformers.
o Remove damaged or leaking in-service smart transformers and replace with
appropriately sized traditional non-smart transformers.
o Do not install a new “smart-transformer.”

 For Transformer Change-Out Program: Determine if multiple pre-1981 padmount
transformers should be changed out during one outage.

62 Reference: DO-4.105, School Electric Facility Document
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 Evaluate the cost effectiveness of the identified for replacement components versus the
cost effectiveness of replacing the pole using “Component Versus Pole Replacement
Analysis Tool”.

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UNDERGROUND

 Consult the Program Administrator for help in evaluating lines with extensive repair
work to identify if the line should be considered for undergrounding. Undergrounding
will require working with the local office for funding assistance and design guidance.

 Evaluate the cost effectiveness of the identified for replacement components versus the
cost effectiveness of replacing the pole using “Component Versus Pole Replacement
Analysis Tool”.

 Riser
o When replacing a riser pole that has multiple phases in a single conduit, re-install
each phase in its own conduit. Replace risers with multiple phases in a single
conduit that does not meet the current standard.63

 Sweeps
o Conduit
 Conduit is preferred on all underground cable installations.
 Direct buried or plowed in is an acceptable practice in justifiable
situations, however it is not preferred.
 Sweeps shall be installed on underground cable systems in conduit.
 Sweeps shall be installed on direct-buried or plowed-in underground cable
systems to maintain minimum bend radius.64
 Sweeps shall be installed on all riser and other above ground transition
installations.

63 Reference: DU-2.116
64 Reference: “Sweeps are required on cable entrance into box pads and ground sleeves” (per email from Marty
Gulsuth, 7-13-17). This decision supersedes the previous memo from Dave James

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 Conduit shall be installed on all three-phase 600 A underground cable
systems.

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WOOD POLES

 Red Tag Poles
o Replace all Red Tag poles as indicated by Wood Pole Inspections.
o Foreign-owned Red Tag poles shall be addressed using the Joint Use coordination
process (see Joint Use section of DFMP – Structure-Specific Programs – Design
Criteria Manual).65

 Yellow Tag Poles
o Yellow Tag poles shall be stubbed regardless of age, except in backyards with no
truck access where all poles shall be replaced. Collectively evaluate the condition
of the pole and other equipment and conductors being replaced to assist in
determining whether to ultimately replace a pole that could be stubbed.66 67
o Foreign-owned Yellow Tag poles shall be addressed using the Joint Use
coordination process.68

 Pole Class
o Evaluate and ensure all to be replaced poles are classed to conform with Avista’s
Distribution Standards.
o Create call-out on design for replacement of any pole that is visibly under-
classed.69 70 71 72

65 Reference: DO-1.426
66 Source: “Asset Management – “2014.12.23 Pole Top and Crossarm Failure Information Rev. 1.pptx”
67 Reference: Specification S-755 – Installation of Steel Stubs on Wood Poles
68 See Joint Use section of DFMP – Structure-Specific Programs – Design Criteria Manual
69 Reference: Avista Distribution Engineering – “Evaluation of Pre-1977 Existing Installations”
70 Reference: Avista Distribution Engineering – “Avista Existing Facilities Replacement Modification Guidelines”
71 Reference: DO-2.625 and DO-2.630
72 Reference: DO-2.620 and DO-4.138
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 Pole Height
o Evaluate the required pole height on all existing, new, or to be replaced poles to
ensure all poles have vertical clearances that conform to Avista’s Distribution
Standards and the NESC Communications Worker Safety Zone Rule 238E.
o Create call-out on design for replacement of any pole that is visibly under-sized
(height). This may require replacing a physically healthy pole with a new pole of
the correct height and/or class, due to new attachments, loading, and uplift caused
by short spans with different pole heights.73 74

 Pole Top
o Evaluate the Pole Top condition to determine if a pole should be replaced. Split
Bolts shall only be added if there are no pre-existing bisecting bolts.
o Determine if “topping the pole” and framing down conform with Avista’s
Distribution Standards.
o Determine if split bolting is necessary to maintain the integrity of the pole top.75

 Woodpecker Hole Evaluation
o Evaluate the size of any Woodpecker holes and the effect on the strength of the
pole.76

 Leaning Poles
o Poles leaning more than three feet from the vertical at the top of the pole shall be
straightened if pole height and class are adequate or replaced with appropriate
height and class pole.77

73 Reference: DO-2.620
74 Reference: Avista Distribution Engineering – “Avista Existing Facilities Replacement Modification Guidelines”
75 Reference: DO-2.000
76 Reference: Specification S-622 – Specification for the Inspection of Wood Poles
77 Reference: Specification S-755 - Avista Installation of Steel Stubs on Wood Poles
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 Idle or Unused Poles
o Remove idle or unused poles. Verification with Avista local construction office
and landowner is required before removal.
o De-energized pole line sections shall be inspected and kept in the same condition
as energized lines.
o De-energized lines should be bonded and grounded to the system neutral at a
minimum.

 Service Poles
o Steel Poles
 Remove all existing steel service poles and replace with appropriate wood
equivalent.

 Wood-Stubbed Poles
o Remove and replace all existing wood-stubbed poles.
o Do not install steel stubs in poles located in backyards due to climbing safety
issues.

 Slack Span
o Considerations should be given for the height, class, and setting depth of a pole
based on soil conditions. Contract Distribution Engineering with any design
related questions on slack spans.

 Vegetation Management
o Designers shall consult vegetation management when applicable for all overhead
construction.

 Customer-Owned Meter Poles
o Do not use customer-owned meter poles to support secondary conductor that
continue on to serve additional customers.

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 Foreign Owned Poles
o Reference operations flip chart for guidance.

 Other
o When replacing and installing with a new pole, do not re-install the existing
insulators, arrestors, or cutouts. Additional materials and equipment can be
determined at the designer’s discretion based on condition.
o Compare the cost of the “Identified For Replacement” components versus the cost
of replacing the entire pole using the “Component Versus Pole Replacement
Analysis Tool” to determine what should be replaced. (Tool needs to have WPM
units instead of GMP unit descriptions and prices.)78 79 80

78 Reference: s DO-1.005
79 General Reference: DFMP – Structure-Specific Programs - Design Criteria Manual - Joint Use Section for the
Notification and Coordination Process document for information on pole issues related with Joint Users.
80 General Reference: DFMP – Structure-Specific Programs - Design Criteria Manual - Vegetation Management
Section for process to contact Avista Vegetation Management Administrator to request tree trimming on their
projects to establish proper clearance from poles and conductors.
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REDUCED SCOPE

 Replace red-tagged poles.

 Reinforce yellow-tagged poles.

 Replace bad cross-arms.

 Repair bad pole tops.

 Replace:
o Broken Insulators
o Broken or Stolen Grounds
o Targeted TCOP Transformers
o Transformers that show signs of leaking

 Remove:
o Idle Transformers
o Idle Poles

 Compare the cost of the “Identified For Replacement” components versus the cost of
replacing the entire pole using the “Component Versus Pole Replacement Analysis Tool” to
determine what should be replaced.81

81 Reference: DO-1.005
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Version Date Action Change Tracking
1 October 2018  Wood Poles
o Service Poles
 Steel Poles
 Remove all existing steel service poles and
replace with appropriate wood equivalent.
(see comment above)
o Wood-Stubbed Poles
 Remove and replace all existing wood-stubbed poles.
 Do not install steel stubs in poles located in backyards
due to climbing safety issues.
o Customer-Owned Meter Poles
 Do not use customer-owned meter poles to support
secondary conductor that continue on to serve
additional customers.  Transformers
o Smart Transformers
 Leave smart transformers in-service if they are
properly sized and not damaged or leaking.
 Remove undersized in-service smart transformers and
replace with appropriately sized traditional non-smart
transformers.
 Remove damaged or leaking in-service smart
transformers and replace with appropriately sized
traditional non-smart transformers.
 Do not install a new “smart-transformer.”
 Underground
o Sweeps
 Conduit  Conduit is preferred on all underground cable installations.  Direct buried or plowed in is an acceptable
practice in justifiable situations, however it
is not preferred.
 Sweeps shall be installed on underground
cable systems in conduit.
 Sweeps shall be installed on direct-buried
or plowed-in underground cable systems
to maintain minimum bend radius.
 Sweeps shall be installed on all riser and
other above ground transition installations.
 Conduit shall be installed on all three-
phase 600 A underground cable systems.
 Conduit shall be installed on all
underground secondary cables.82
o Riser
 When replacing a riser pole that has multiple phases
in a single conduit, re-install each phase in its own
conduit. Replace risers with multiple phases in a
single conduit that does not meet the current
standard.83
 OH Conductor
o Slack Span
 Considerations should be given for the height, class,
and setting depth of a pole based on soil conditions.
Contract Distribution Engineering with any design
related questions on slack spans.
o Customer-Owned Meter Poles
 Do not use customer-owned meter poles to support
secondary conductor that continue on to serve additional customers.
Revisions

82 “Sweeps are required on cable entrance into box pads and ground sleeves” (per email from Marty Gulsuth, 7-13-
17.) This decision supersedes the previous memo from Dave James.
83 DU-2.116
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o Roof Horses84
 Do not install new roof horses.  Remove service from roof horse if there is a clearance
violation, roof horse is damaged, or work is being
performed on the service. (See note above)  This may involve installing a new service pole or
relocating the service connection to the secondary.85
o Vegetation Management
 Designers shall consult vegetation management with
applicable for all overhead construction.

84 It references having to horse the service over the roof to a meter. They also actually observed where someone
nailed a saw horse to their roof hence Saw horse/ Roof Horse.
85 NESC 217B
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