UNITED STATES DEPARTMENT OF AGRICULTURE 

Rural Utilities Service 

RUS BULLETIN 1728F-804

SUBJECT: Specifications and Drawings for 12.47/7.2 kV Line Construction

Incorporated by reference in 7 CFR Part 1728

TO: All RUS Electric Borrowers 

 RUS Electric Staff 

EFFECTIVE DATE: October 2005

OFFICE OF PRIMARY INTEREST: Distribution Branch, Electric Staff Division 

FILING INSTRUCTIONS: This bulletin is a revision of previous RUS Bulletin 50-3 

(D-804), (dated May 9, 1983) “Specifications and Drawings for 12.5/7.2 kV Line Construction” 

and has been renumbered, renamed and updated as RUS Bulletin 1728F-804, “Specifications and 

Drawings for 12.47/7.2 kV Line Construction.” Replace previous Bulletin 50-3 with this 

bulletin. This bulletin should be filed with 7 CFR 1728. 

PURPOSE: The specifications and drawings of this bulletin have been published to set forth 

RUS requirements, specifications and standards for the construction of 12.47/7.2 kV overhead 

electric distribution lines and associated equipment and construction assembly units that RUS 

electric borrowers install. 

GENERAL: This new bulletin 1728F-804 was derived from previous RUS Bulletin 50-3 

identified above. Listed below are some of the significant changes and additions that were made 

during the update of this bulletin: 

(a) RUS has discontinued 82 assemblies and 24 guide drawings previously in 

Bulletin 50-3. Borrowers shall no longer use these discontinued assemblies and 

guide drawings for new construction. 

(b) A total of 167 assemblies and 8 guide drawings were re-used, redrawn, and 

renumbered using the new RUS standard numbering format. (New Exhibit 5 at the 

end of the bulletin briefly explains the new numbering format.) The new drawings 

of these re-used assemblies and guide drawings show in parentheses the old 

assembly and guide drawing numbers from Bulletin 50-3. Borrowers must use the 

new assembly and guide drawing numbers, however, borrowers may elect to 

continue using the old numbers of these assembly and guide drawings, but only 

for the 167 assemblies and 8 guide drawings and their old numbers if they make 

the following changes:
 (1) Make washer additions or changes on 37 of the re-used assemblies, and, 

 (2) Make other slight material changes to 35 of the old assemblies. 

(c) Exhibit 3 at the end of this bulletin tabulates: (1) all of the discontinued assemblies 

and guide drawings of old Bulletin 50-3, (2) all of the re-used assemblies and 

guide drawings with both their old and new numbers, and (3) the required washer 

and material changes (if any) in the transition from the re-used old assembly to the 

new assembly. 

(d) This new bulletin contains a total of 214 new assemblies (95 of which are narrow 

profile assemblies) and 32 new guide drawings. 

(e) The bulletin has been reformatted into 19 separate sections or categories. Each of 

the sections contains an index of drawings and the construction drawings of 

assemblies designed to perform a similar function. Ten of the sections contain 

new and revised construction specifications and informational details pertaining to 

the assemblies within the section. 

(f) "Design parameters", which define and usually limit maximum line angles or 

mechanical loading (tension), have been added to most of the drawings. 

(g) New tables have been added to define maximum line angles on pole top assemblies 

and permitted unbalanced conductor tensions on crossarm assemblies. Page 1 of 

Exhibit 1 documents the formula and data used to determine the maximum line 

angles in the tables in Exhibit 1. Exhibit 2 documents the formula and data used to 

determine permitted unbalanced conductor tensions on crossarms. 

(h) Each drawing has been given a new, shorter, and more uniform title or name. 

(i) Three sets of coordinated “narrow profile,” one, two and three-phase assemblies 

for all line angles have been incorporated into this bulletin. 

(j) New specifications explaining the conditions that borrowers may modify the 

assemblies and drawings of this bulletin are provided in the “General Construction 

Specifications.” 

(k) New specifications and conditions for the use of stirrups were added in Section L. 

(l) New specifications and conditions for grounding or insulating guy wires were 

added in Section G. 

April 1, 2005 

____________________________ _________________ 

Curtis M. Anderson Date 

Acting Administrator 

Rural Utilities Service 
BULLETIN 1728F-804: INDEX

SECTION CATEGORY DESCRIPTIONS

1-a General Construction Specifications

1-b Conductor Installation Specifications

1-c Construction Specifications for Pole Top Assemblies

1-d Narrow Profile Assemblies Grouped by Bracket Configuration

A SINGLE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS

Index A

Single-Phase Primary Pole Top Construction Drawings

B TWO-PHASE PRIMARY POLE TOP ASSEMBLY UNITS

Index B

Two-Phase Primary Pole Top Construction Drawings

C THREE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS

Index C

Three-Phase Primary Pole Top Construction Drawings

D DOUBLE-CIRCUIT PRIMARY POLE TOP ASSEMBLY UNITS

Index D

Double-Circuit Primary Pole Top Construction Drawings

E GUYING ASSEMBLY UNITS

Index E

Construction Specifications for Guys

Guying Construction Drawings

F ANCHOR ASSEMBLY UNITS

Index F

Construction Specifications for Anchoring

Soil Classifications (Table)

Anchor Construction Drawings

G TRANSFORMER ASSEMBLY UNITS

Index G

Construction Specifications for Transformers

Transformer Construction Drawings

H GROUNDING ASSEMBLY UNITS

Index H

Construction Specifications for Grounding

Grounding Construction Drawings
BULLETIN 1728F-804: INDEX (Continued)

SECTION CATEGORY DESCRIPTIONS

J SECONDARY ASSEMBLY UNITS

Index J

Construction Specifications for Secondary Conductors and Services

Secondary Construction Drawings

K SERVICE ASSEMBLY UNITS

Index K

Service Construction Drawings

L TYING ASSEMBLY UNITS

Index L

Construction Specifications for Connectors, Stirrups, Clamps, 

Taps and Jumpers

Tying Guide Drawings

M MISCELLANEOUS ASSEMBLY UNITS AND GUIDES

Index M

Right-of-Way Clearing Specifications

Miscellaneous Construction Drawings and Guides

N NEUTRAL ASSEMBLY UNITS

Index N

Neutral Construction Drawings

P PROTECTION ASSEMBLY UNITS

Index P

Construction Specifications for Raptor Protection

Protection Construction Drawings

Q METERING ASSEMBLY UNITS

Index Q

Metering Construction Drawings

R OIL CIRCUIT RECLOSER ASSEMBLY UNITS

Index R

Oil Circuit Recloser Construction Drawings

S SECTIONALIZING ASSEMBLY UNITS

Index S

Sectionalizing Construction Drawings
BULLETIN 1728F-804: INDEX (Continued)

SECTION CATEGORY DESCRIPTIONS

W WOOD POLES, CROSSARMS AND BRACES

Index W

Construction Specifications for Poles and Crossarms

Pole Setting Depths (Table)

Pole and Crossarm Guides and Assembly Drawings

Y VOLTAGE ALTERATION EQUIPMENT ASSEMBLY UNITS

Index Y

Voltage Alteration Equipment Construction Drawings

EXHIBITS

1 CALCULATIONS AND TABLES OF MAXIMUM LINE ANGLES

Calculation of Maximum Line Angles

Table I: Maximum Line Angles (Pin Insulators) - 500 lbs./Conductor

Table II: Maximum Line Angles (Pin Insulators) - 750 lbs./Conductor

Table III: Maximum Line Angles (Pin Insulators) - 1,000 lbs./Conductor

Table IV: Maximum Line Angles (Pin Insulators) - 1,500 lbs./Conductor

Table V: Maximum Line Angles (Pin Insulators) - 2,000 lbs./Conductor

Table VI: Maximum Line Angles (Spool Insulators) - 1,500 lbs./Conductor

Table VII: Maximum Line Angles (Spool Insulators) - 2,250 lbs./Conductor

2 LONGITUDINAL LOADING ON CROSSARM ASSEMBLIES

TABLE A: Permitted Unbalanced Conductor Tension - (1 phase/side of pole)

TABLE B: Permitted Unbalanced Conductor Tension - (2 phases/side of pole)

3 DISPOSITION OF ASSEMBLIES IN BULLETIN 50-3 (D 804)

4 NEW ASSEMBLIES AND GUIDE DRAWINGS IN BULLETIN 1728F-804

5 RUS STANDARD FORMAT AND MEANING OF OVERHEAD

DISTRIBUTION ASSEMBLY NUMBERS

6 TABLE OF SELECTED SI TO METRIC CONSVERSIONS
Bulletin 1728F-804 

Section 1-a 

GENERAL CONSTRUCTION SPECIFICATIONS

All construction shall be performed in a safe, thorough, and skillful manner in accordance with 

the staking sheets, plans and specifications, and the construction drawings. 

The provisions of 7 CFR 1724.50, “Compliance with National Electrical Safety Code (NESC)” 

apply to all borrower electric system facilities regardless of the source of financing. A borrower 

must ensure that its electric system including all distribution, transmission, and generating 

facilities, is designed, constructed, operated, and maintained in accordance with all of the 

applicable provisions of: 

(1) the most current provisions of the NESC, and 

(2) all applicable and current electrical and safety requirements of any State or local 

governmental entity. 

Any electrical standard requirements established by RUS are in addition to, and not a 

substitution for nor modification of (1) and (2) listed immediately above. 

The permitted loading, strength, and spacing (separation) of structures, assemblies and 

conductors shown on the assembly drawings in this bulletin are based on and are in compliance 

with the 2002 Edition of the NESC. 

Copies of the NESC may be obtained from the Institute of Electrical and Electronics Engineers, 

Inc., (IEEE) at the following address: 

 IEEE Customer Service 

 445 Hoes Lane, PO Box 1331 

 Piscataway, NJ 08855-1331 

 Telephone: 1-800-678-4333 

Overhead distribution circuits shall be constructed with not less than the Grade C strength 

requirements as described in section 26, Strength Requirements, of the NESC when subjected to 

the loads specified in NESC Section 25, Loadings for Grades B and C. Distribution lines that 

underbuild transmission circuits or that cross over limited access highways and railroad tracks 

shall be constructed with not less than the Grade B strength requirements as described in NESC 

Section 26. 

The drawings of equipment and materials shown in the construction assemblies depict the 

general categories of items found in RUS Informational Publication 202-1, “List of Materials 

Acceptable for Use on Systems of RUS Electrification Borrowers” (“List of Materials”). Any 

drawing of any piece of equipment or material that resembles a specific product of a 

manufacturer is unintentional. 
Bulletin 1728F-804 

Section 1-a 

GENERAL CONSTRUCTION SPECIFICATIONS (Cont.) 

Materials to be used for construction are designated by one or two lower-case alphabetic 

characters shown on the drawings and in the “ITEM” column in the drawing material blocks. 

For example, “b” designates a steel, pole top pin. A borrower shall use, at its discretion, any of 

the applicable pole top pins from category “b” of the “List of Materials 

The drawings in this bulletin show the use of two, 4 1/4 inch, American National Standards 

Institute (ANSI) Class 52-9A suspension insulators for 12.47/7.2 kV primary deadends. 

However, borrowers may alternatively use two, 6-inch, ANSI Class 52-1 suspension insulators, 

or one polymer distribution insulator, all of which are contained in category “k” in the “List of 

Materials.” In the case of polymer insulators, the quantity (“QTY”) of the insulators to be used 

must be modified accordingly in the material blocks of the drawings. 

Normally crossarm pins and post-type insulators come equipped with washers and locknuts. 

Thus, the washers and locknuts for crossarm pins are not tallied in the “QTY” (quantity) 

columns in the material boxes on the construction drawings. However, the crossarm pin washers 

and locknuts are shown on the construction drawings in parenthesis to depict proper 

construction. If crossarm pins or post type insulators are purchased without washers, locknuts or 

studs, the quantity totals in the material boxes on the construction drawings will need to be 

adjusted accordingly. 

Locknuts shall be installed on all threaded material and hardware in addition to nuts and 

washers. The threads on installed bolts shall protrude past the lock washers a minimum of one 

inch but not more than two inches. 

Sometimes it may be prudent or necessary to modify RUS standard distribution assemblies to 

solve encountered construction problems. For example, a standard C6.1 assembly may need to 

be modified with heavy-duty crossarm braces (assembly W3.2) to support large conductors. 

RUS has not produced the scores of new assemblies like the example because the resulting 

bulletin would be quite unwieldy. Therefore, borrowers themselves may develop and use 

assemblies similar to the example without additional RUS approval. Borrowers’ assemblies not 

specifically approved by RUS shall not have component spacing less than, or permitted 

longitudinal loads (strengths) greater than those on correlated RUS standard assemblies. 

Borrowers need to properly account for the new assembly material and assign assembly numbers 

recognizably different than RUS standard assembly numbers. 

RUS approval and assembly number changes are not required to add the following types of 

information to RUS assembly drawings: material inventory numbers, bolt lengths, jumper wire 

sizes, types of connectors, armor rods, etc. 
Bulletin 1728F-804 

Section 1-b 

CONDUCTOR INSTALLATION SPECIFICATIONS

Conductors shall be handled with care and shall not be trampled on or run over by vehicles. 

Each reel shall be examined and the wire shall be inspected for cuts, kinks, or other damage. 

Damaged portions shall be cut out and the conductor spliced. The conductors shall be pulled 

over suitable rollers or stringing blocks properly mounted on the pole or crossarm to prevent 

binding or damage while stringing. 

Conductors shall be sagged evenly and in accordance with the conductor manufacturer's 

recommendations. The air temperature at the time and place of sagging shall be determined by 

the use of a certified thermometer. The sag of all conductors after stringing shall be in 

accordance with the engineer's instructions. 

For new construction, splices shall be no closer than 1,000 feet from one another and there shall 

be no more than 3 splices per mile in any primary phase or neutral conductor. Furthermore, 

splices shall not be located within 10 feet of any supporting structure. For all construction, 

splices shall not be located in Grade B crossing spans and preferably not in adjacent spans. 

Splices shall be installed in accordance with the manufacturer's specifications and 

recommendations. 

All conductors shall be cleaned thoroughly by wirebrushing before splicing or installing 

connectors or clamps. A suitable oxidation inhibitor shall be applied before splicing or applying 

connectors over aluminum conductor. 
Bulletin 1728F-804 

Section 1-c 

CONSTRUCTION SPECIFICATIONS FOR POLE TOP ASSEMBLIES

The neutral conductor shall be installed on the same side (preferably the roadside) of all tangent 

and small angle poles throughout each line section. See “Construction Specifications for Poles 

and Crossarms” in Section W of this bulletin for additional pole and crossarm construction 

specifications. 

Neutral attachments may be lowered on standard pole top assemblies a distance not exceeding 

2 feet for the purpose of economically meeting conductor clearance requirements of the NESC. 

Neutral attachments may be lowered on standard pole top assemblies a distance not exceeding an 

additional 6 feet for the purpose of performing construction and future line maintenance on these 

assemblies from bucket trucks designed for such work. 

The conductor shall be tied to the top groove of pin-type or post-type insulators on tangent poles. 

On angle structures the conductor shall be tied on the side of the insulator opposite the direction 

of the strain. Pin-type and post-type insulators shall be tight on the pins and brackets, 

respectively, and the top groove shall be in line with the conductor after tying. Borrowers shall 

not allow any upstrain on pin-type or post-type insulators. 

A 3 inch by 3 inch (minimum), square, curved washer (item “d”) shall be used abutting the pole 

when installing primary deadend, neutral deadend and guy assemblies directly to the pole. These 

washers mitigate the crushing of wood fibers and facilitate the permitted longitudinal loads 

shown on the construction drawings. 

A 2 1⁄4 inch (minimum) square washer shall be placed under the shoulder of 7.2 kV crossarm 

insulator pins whose surface area abutting the crossarm is less than 4 square inches. These 

washers mitigate the crushing of wood fibers and facilitate the permitted transverse loading 

shown in the maximum line angle tables in Exhibit 1. 

The maximum line angles on tangent construction assemblies shall be limited to 5 degrees for 

small conductors and 2 degrees for conductors larger than # 1/0 because of likely slippage of the 

neutral conductor off of a spool-type insulator. Furthermore, based on additional calculations by 

the design engineer, these maximum line angles may need to be reduced for NESC Grade B 

construction. 

Deadend and suspension angle pole top assemblies attached directly to poles shall be designed to 

hold the sum of all expected loads multiplied by the appropriate overload factors of NESC Table 

253-1. 

RUS has applied the applicable strength factors for Grade C construction from 

NESC Table 261-1A in the calculations for permitted longitudinal loading shown in the design 

parameters on the drawings. The permitted longitudinal loading on primary deadend assemblies 

attached directly to poles is based on 50 percent of the rated ultimate strength of the suspension 

insulators shown on the assembly drawings. 
Bulletin 1728F-804 

Section 1-c 

CONSTRUCTION SPECIFICATIONS FOR POLE TOP ASSEMBLIES (cont.)

The maximum line angles for pole top primary assemblies in the tables in Exhibit 1 are based on 

the RUS designated maximum load on crossarm insulator pins, post type insulators, or pole top 

pins and the assumed conductor tensions tabulated on page 1 of Exhibit 1. The applicable 

overload factors from NESC Table 253-1, for Grade C construction, have already been applied 

in the calculations for the maximum line angles. For large conductor sizes, the design engineer 

may need to calculate new (smaller) maximum line angles for NESC Grade B construction. 

The permitted unbalanced conductor tensions on primary deadend assemblies attached to 

crossarms are based on the results of the equations and methodology explained in Exhibit 2 of 

this bulletin. RUS has applied the overload factors of NESC Table 253-1 and used the assumed 

conductor tensions tabulated on page 1 of Exhibit 1 to calculate the permitted unbalanced 

conductor tensions shown in Tables A and B of Exhibit 2 of this bulletin. The permitted 

unbalanced conductor tensions on crossarm assemblies shall be reduced by 40 percent for NESC 

Grade B construction.

 

RUS categorizes conductor sizes as follows: 

• Small conductors are conductors with a rated breaking strength of less than 4,500 pounds 

(20,000 newtons), e.g., 1/0 Aluminum Conductor - Steel Reinforced (ACSR) and smaller. 

• Large conductors are conductors with a rated breaking strength of 4,500 pounds 

(20,000 newtons) or greater but less than 10,000 pounds (45,000 newtons), e.g., 2/0 ACSR 

through 4/0 ACSR or 336.4 kcmil (18/1) ACSR. 

• Extra large conductors are conductors with a rated breaking of 10,000 pounds 

(45,000 newtons) or greater, e.g., 266.8 kcmil (26/7) ACSR and larger. 

Primary pole top assemblies identified as “large conductors” in the drawing titles shall be used to 

support large and extra large conductors. Large conductor assemblies may also be used for small 

conductors. Furthermore, large and extra large conductors may be installed on assemblies not 

designated as large conductors provided that the expected transverse or longitudinal loads 

(multiplied by the appropriate NESC overload factors) do not exceed the permitted loads or 

tensions shown on the design parameters of the drawings. For any conductor size, the 

horizontal, vertical or transverse loads shall not exceed the permitted strength of crossarms, 

crossarm pins, insulators, or insulator bracket assemblies. Usually, extra large conductors 

require that pin type and post type insulators have a “C” neck for conductor sizes up through 

477.0 (18/1) ACSR and “J” necks for conductor sizes up to 795 kcmil, depending on the armor 

rods selected. 
Bulletin 1728F-804

Section 1-d

`

(APPLICATIONS: Convert existing standard 1-phase; Standard pole framing)

MAX. LINE ANGLES 1-PHASE 2-PHASE 3-PHASE

Tangent A1.1, A1.2 B1.1N, B1.2N C1.1N, C1.2N

 " A1.1P, A1.2P B1.1NP, B1.2NP C1.1NP, C1.2NP

 " (NESC Grade B) A2.1, A2.2 B2.1N, B2.2N C2.1N, C2.2N

 " (NESC Grade B) A2.1P, A2.2P B2.1NP, B2.2NP C2.1NP, C2.2NP

Table I A1.3 B1.3N C1.3N

Table II A1.3P B1.3NP C1.3NP

Table III A2.3 B2.3N C2.3N

Table III C2.3NG

Table IV A2.3P B2.3NP C2.3NP

"STAGGERED" ASSEMBLIES ( 2-foot spacing )

MAX. LINE ANGLES 1-PHASE 2-PHASE 3-PHASE

Tangent A1.4N, A1.5N B1.4N, B1.5N C1.4N, C1.5N

 " A1.4NP, A1.5NP B1.4NP, B1.5NP C1.4NP, C1.5NP

 " (NESC Grade B) A2.4N, A2.5N B2.4N, B2.5N C2.4N, C2.5N

 " (NESC Grade B) A2.4NP, A2.5NP B2.4NP, B2.5NP C2.4NP, C2.5NP

Table II A1.6N B1.6N C1.6N

Table II A1.6NP B1.6NP C1.6NP

Table IV A2.6N B2.6N C2.6N

Table IV A2.6NP B2.6NP C2.6NP

"VERTICAL" ASSEMBLIES ( 4-foot spacing )

 (APPLICATIONS: Large line angles; Tree and building clearances)

MAX. LINE ANGLES 1-PHASE 2-PHASE 3-PHASE

Tangent B1.7N, B1.8N C1.7N, C1.8N

(APPLICATIONS: New construction; Transmission underbuild)

 NARROW PROFILE ASSEMBLIES GROUPED BY BRACKET CONFIGURATION

"STANDARD" ASSEMBLIES ( 1-foot, 9-inch spacing )

( Same as

 " B1.7NP, B1.8NP C1.7NP, C1.8NP

 " (NESC Grade B) ( SamB2.7N, B2.8N C2.7N, C2.8N e as

"Staggered"

 " (NESC Grade B) B2.7NP, B2.8NP C2.7NP, C2.8NP

Table II B1.9N C1.9N

Assemblies )

"Staggered"

Table II B1.9NP C1.9NP

Table IV B2.9N C2.9N

Table IV B2.9NP C2.9NP

MISC. ASSEMBLIES

A1.04N, A1.04NP Single support brackets and insulators (Single-phase, Table II)

A2.04N, A2.04NP Double support brackets and insulators (Single-phase, Table IV)

A5.3NG Single-phase tap guide (Narrow profile)

A5.4NG Single-phase tap guide with cutout and arrester (Narrow profile)

D1.4N, D1.4NP Single support - Double-circuit ("Staggered assembly", Tangent)

D1.45, D1.5NP Single support - Double-circuit ("Staggered assembly", Tangent)

D2.9N, D2.9NP Double support - Double-circuit ("Vertical assembly", Table IV)

P1.1NG Surge arrester on narrow profile bracket (Single-phase, Guide)

S1.1N Cutout on narrow profile bracket (Single-phase)

Note: Number suffixes "N", "P", and "G" denote Narrow profile assembly, Post type insulator assembly,

 and Guide drawing (no materials), respectively.

Assemblies )
INDEX A 

SINGLE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

A1.01 (M5-2) SINGLE SUPPORT - PRIMARY 

A1.01P (M5-18) 

A1.011 (M5-5) 

A1.011P (M5-7) 

A1.011L 

 

A1.04N SINGLE SUPPORT – NARROW PROFILE 

A1.04NP 

 

A1.1 (A1) SINGLE SUPPORT (TANGENT) 

A1.2 (A1A) 

 

A1.1P (A1P) SINGLE SUPPORT (TANGENT) (POST INSULATORS) 

A1.2P (A1AP) 

 

A1.3 SINGLE SUPPORT 

 

A1.3P SINGLE SUPPORT (POST INSULATORS) 

 

A1.4N SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

A1.5N 

 

A1.4NP SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

A1.5NP (POST INSULATORS) 

 

A1.6N SINGLE SUPPORT – NARROW PROFILE 

 

A1.6NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

A1.11 (A9-1) SINGLE SUPPORT ON CROSSARM 

 

A1.11P (A9-1P) SINGLE SUPPORT ON CROSSARM (POST INSULATORS) 

 

A1.12G SINGLE PHASE JUNCTION GUIDE 

 

A2.01 DOUBLE SUPPORT - PRIMARY 

A2.01P 

A2.021 

A2.021P 

 

A2.04N DOUBLE SUPPORT – NARROW PROFILE 

A2.04NP 

 

A2.1 (A1-1) DOUBLE SUPPORT (TANGENT) 

A2.2 (A1-1A) 
INDEX A 

(Page 2) 

SINGLE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

A2.1P (A1-1P) DOUBLE SUPPORT (TANGENT) (POST INSULATORS) 

A2.2P (A1-1AP) 

 

A2.3 (A2) DOUBLE SUPPORT 

 

A2.3P (A2P) DOUBLE SUPPORT (POST INSULATORS) 

 

A2.4N DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

A2.5N 

 

A2.4NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

A2.5NP (POST INSULATORS) 

 

A2.6N DOUBLE SUPPORT – NARROW PROFILE 

 

A2.6NP DOUBLE SUPPORT – NARROW PROFILE 

 (POST INSULATORS) 

 

A2.21 (A9) DOUBLE SUPPORT ON CROSSARMS 

 

A2.21P (A9P) DOUBLE SUPPORT ON CROSSARMS (POST INSULATORS) 

 

A3.1 (A3) SUSPENSION ANGLE 

A3.2 

A3.3 

 

A3.4 SUSPENSION ANGLE 

A3.5 

A3.6 

A3.7 

A3.8 

A3.9 

 

A4.1 (A4) DEADEND ANGLE (90° - 150°) 

 

A4.2 DEADEND ANGLE (15° - 90°) 

 

A5.01 (M5-24) SINGLE DEADENDS 

A5.02 (M5-8) 

A5.03 

 

A5.1 (A5) SINGLE DEADENDS 

A5.2 (A5-2) 

A5.3 
INDEX A 

(Page 3) 

SINGLE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

A5.4 SINGLE DEADENDS 

A5.5 

A5.6 

A5.7 

A5.8 

A5.9 

 

A5.2G SINGLE PHASE TAP GUIDE 

 

A5.3NG SINGLE PHASE TAP GUIDE – NARROW PROFILE 

 

A5.4NG SINGLE PHASE TAP GUIDE – NARROW PROFILE 

 (WITH CUTOUT AND ARRESTER) 

 

A5.21 (A7) SINGLE DEADEND ON CROSSARMS 

A5.31 (A7-1) 

 

A6.1 (A6) DOUBLE DEADEND (STRAIGHT) 

 

A6.2 DOUBLE DEADEND (FEED THROUGH) 

 

A6.21 (A8) DOUBLE DEADEND ON CROSSARMS 

 

A6.22G DOUBLE DEADEND GUIDE (FEED THROUGH ON 

CROSSARMS) 

 








































INDEX B 

TWO-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

B1.1N SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

B1.2N 

 

B1.1NP SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

B1.2NP (POST INSULATORS) 

 

B1.3N SINGLE SUPPORT – NARROW PROFILE 

 

B1.3NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

B1.4N SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

B1.5N 

 

B1.4NP SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

B1.5NP (POST INSULATORS) 

 

B1.6N SINGLE SUPPORT – NARROW PROFILE 

 

B1.6NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

B1.7N SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

B1.8N 

 

B1.7NP SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

B1.8NP (POST INSULATORS) 

 

B1.9N SINGLE SUPPORT – NARROW PROFILE 

 

B1.9NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

B1.11 (B1) SINGLE SUPPORT ON CROSSARM (TANGENT) 

B1.12 (B1A) 

 

B1.11P (B1P) SINGLE SUPPORT ON CROSSARM (TANGENT)

B1.12P (B1AP) (POST INSULATORS) 

 

B1.13 SINGLE SUPPORT ON CROSSARM 

 

B1.13P SINGLE SUPPORT ON CROSSARM (POST INSULATORS) 

 
INDEX B 

(Page 2) 

TWO-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

B1.14 (B9-1) SINGLE SUPPORT, NEUTRAL ON CROSSARM 

 

B1.14P (B9-1P) SINGLE SUPPORT, NEUTRAL ON CROSSARM 

 (POST INSULATORS) 

 

B2.1N DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

B2.2N 

 

B2.1NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

B2.2NP (POST INSULATORS) 

 

B2.3N DOUBLE SUPPORT – NARROW PROFILE 

 

B2.3NP DOUBLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

B2.4N DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

B2.5N 

 

B2.4NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

B2.5NP (POST INSULATORS) 

 

B2.6N DOUBLE SUPPORT – NARROW PROFILE 

 

B2.6NP DOUBLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

B2.7N DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

B2.8N 

 

B2.7NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

B2.8NP (POST INSULATORS) 

 

B2.9N DOUBLE SUPPORT – NARROW PROFILE 

 

B2.9NP DOUBLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

B2.21 (B2) DOUBLE SUPPORT ON CROSSARMS 

 

B2.21P (B2P) DOUBLE SUPPORT ON CROSSARMS (POST INSULATORS) 

 

B2.22 (B9) DOUBLE SUPPORT, NEUTRAL ON CROSSARMS 

 

B2.22P (B9P) DOUBLE SUPPORT, NEUTRAL ON CROSSARMS 

 (POST INSULATORS) 
INDEX B 

(Page 3) 

TWO-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

B2.24 (B1-1) DOUBLE SUPPORT ON CROSSARMS - TANGENT 

B2.25 (B1-1A) 

 

B2.24P (B1-1P) DOUBLE SUPPORT ON CROSSARMS - TANGENT 

B2.25P (B1-1AP) (POST INSULATORS) 

 

B3.1 (B3) SUSPENSION ANGLE 

B3.2 

B3.3 

 

B3.4 SUSPENSION ANGLE 

B3.5 

B3.6 

B3.7 

B3.8 

B3.9 

 

B4.1G ((B4-1)) DEADEND ANGLE GUIDE (90o – 150o) 

 

B4.2G DEADEND ANGLE GUIDE (15o – 90o) 

 

B5.1 (B5-1) SINGLE DEADENDS 

B5.2 

B5.3 

 

B5.4 SINGLE DEADENDS 

B5.5 

B5.6 

B5.7 

B5.8 

B5.9 

 

B5.21 (B7) SINGLE DEADEND ON CROSSARMS 

B5.31 (B7-1) 

 

B6.21 (B8) DOUBLE DEADEND CROSSARMS 

 












































INDEX C 

THREE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

C1.1N SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

C1.2N 

 

C1.1NP SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

C1.2NP (POST INSULATORS) 

 

C1.3N SINGLE SUPPORT – NARROW PROFILE 

 

C1.3NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

C1.4N SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

C1.5N 

 

C1.4NP SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

C1.5NP (POST INSULATORS) 

 

C1.6N SINGLE SUPPORT – NARROW PROFILE 

 

C1.6NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

C1.7N SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

C1.8N 

 

C1.7NP SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

C1.8NP (POST INSULATORS) 

 

C1.9N SINGLE SUPPORT – NARROW PROFILE 

 

C1.9NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

C1.11 (C1) SINGLE SUPPORT ON CROSSARM (TANGENT) 

C1.12 (C1A) 

 

C1.11L (C1-2) SINGLE SUPPORT ON CROSSARM (TANGENT)

C1.12L (LARGE CONDUCTORS) 

 

C1.11P (C1P) SINGLE SUPPORT ON CROSSARM (TANGENT)

C1.12P (C1AP) (POST INSULATORS) 

 

C1.13 SINGLE SUPPORT ON CROSSARM 

 

C1.13L (C1-4) SINGLE SUPPORT ON CROSSARM 

 (LARGE CONDUCTORS) 

 

C1.13P SINGLE SUPPORT ON CROSSARM 

 (POST INSULATORS) 
INDEX C 

(Page 2) 

THREE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

C1.41 (C9-1) SINGLE SUPPORT, NEUTRAL ON CROSSARM 

 

C1.41L (C9-3) SINGLE SUPPORT, NEUTRAL ON CROSSARM 

 (LARGE CONDUCTORS) 

 

C1.41P (C9-1P) SINGLE SUPPORT, NEUTRAL ON CROSSARM 

 (POST INSULATORS) 

 

C1.81G THREE-PHASE JUNCTION GUIDE 

 

C2.1N DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

C2.2N 

 

C2.1NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

C2.2NP (POST INSULATORS) 

 

C2.3N DOUBLE SUPPORT – NARROW PROFILE 

 

C2.3NG DOUBLE SUPPORT – NARROW PROFILE 

 (ALTERNATIVE GUYING GUIDE) 

 

C2.3NP DOUBLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

C2.4N DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

C2.5N 

 

C2.4NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

C2.5NP (POST INSULATORS) 

 

C2.6N DOUBLE SUPPORT – NARROW PROFILE 

 

C2.6NP DOUBLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

 

C2.7N DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

C2.8N 

 

C2.7NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

C2.8NP (POST INSULATORS) 

 

C2.9N DOUBLE SUPPORT – NARROW PROFILE 

 

C2.9NP DOUBLE SUPPORT – NARROW PROFILE (POST INSULATORS) 
INDEX C 

(Page 3) 

THREE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

C2.21 (C2) DOUBLE SUPPORT ON CROSSARMS 

 

C2.21L (C1-3) DOUBLE SUPPORT ON CROSSARMS 

 (LARGE CONDUCTORS) 

 

C2.21P (C1-3P) DOUBLE SUPPORT ON CROSSARMS 

 (POST INSULATORS) 

 

C2.24 (C1-1) DOUBLE SUPPORT ON CROSSARMS - TANGENT 

C2.25 (C1-1A) 

 

C2.24P (C1-1P) DOUBLE SUPPORT ON CROSSARMS - TANGENT 

C2.25P (C1-1AP) (POST INSULATORS) 

 

C2.51 (C9) DOUBLE SUPPORT, NEUTRAL ON CROSSARMS 

 

C2.51L (C9-2) DOUBLE SUPPORT, NEUTRAL ON CROSSARMS 

 (LARGE CONDUCTORS) 

 

C2.51P (C9-2PL) DOUBLE SUPPORT, NEUTRAL ON CROSSARMS 

 (POST INSULATORS) 

 

C2.52 (C2-1) DOUBLE SUPPORT ON 10-FOOT CROSSARMS 

 

C2.52L (C2-2) DOUBLE SUPPORT ON 10-FOOT CROSSARMS 

 (LARGE CONDUCTORS) 

 

C2.52P (C2-2PL) DOUBLE SUPPORT ON 10-FOOT CROSSARMS

 (POST INSULATORS) 

 

C3.1 (C3) SUSPENSION ANGLE 

C3.2 

C3.3 

 

C3.4 SUSPENSION ANGLE 

C3.5 

C3.6 

C3.7 

C3.8 

C3.9 

 

C3.1L (C3-1) SUSPENSION ANGLE (LARGE CONDUCTORS) 
INDEX C 

(Page 4) 

THREE-PHASE PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

C4.1G ((C4-1)) DEADEND GUIDE (90O – 150O) 

 

C4.2G DEADEND GUIDE (15O

 – 90O) 

 

C5.1 SINGLE DEADENDS - VERTICAL 

C5.2 (C5-1) 

C5.3 

 

C5.4 SINGLE DEADENDS - VERTICAL 

C5.5 

C5.6 

C5.7 

C5.8 

C5.9 

 

C5.11G SINGLE PHASE TAP GUIDE

C5.21 (C7) SINGLE DEADEND ON CROSSARMS

C5.31 (C7-1)

C5.21L SINGLE DEADEND ON CROSSARMS (LARGE CONDUCTORS)

C5.32L

C5.22 (C7-2) SINGLE DEADEND ON CROSSARMS - ALTERNATIVE

C5.32

 

C5.71L (C7A) SINGLE DEADEND ON CROSSARM ASSEMBLY 

 

C5.82G THREE PHASE HORIZONTAL TAP GUIDE 

 

C6.21 (C8) DOUBLE DEADEND ON CROSSARMS 

C6.31 

 

C6.21L DOUBLE DEADEND ON CROSSARMS (LARGE CONDUCTORS) 

C6.31l (C8-3) 

 

C6.52 DOUBLE DEADEND ON 10-FOOT CROSSARMS 

C6.53 

 

C6.52G DOUBLE DEADEND ON 10-FOOT CROSSARMS 

 (FEEDTHROUGH GUIDE) 

 

C6.91G DOUBLE DEADENDS (BUCKARMS) GUIDE 

 
































































INDEX D 

DOUBLE CIRCUIT PRIMARY POLE TOP ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

D1.4N SINGLE SUPPORT - NARROW PROFILE (TANGENT)

D1.4NP (and POST INSULATORS) 

D1.5N 

D1.5NP 

 

D1.81 (DC-C1) SINGLE SUPPORT ON CROSSARMS (TANGENT) 

D1.82 

 

D1.81L SINGLE SUPPORT ON CROSSARMS (TANGENT) 

D1.82L (LARGE CONDUCTORS) 

 

D1.81P SINGLE SUPPORT ON CROSSARMS (TANGENT) 

D1.82P (POST INSULATORS) 

 

D1.83 SINGLE SUPPORT ON CROSSARMS 

 

D1.83L SINGLE SUPPORT ON CROSSARMS 

 (LARGE CONDUCTORS) 

 

D1.83P SINGLE SUPPORT ON CROSSARMS 

 (POST INSULATORS) 

 

D2.9N DOUBLE SUPPORT - NARROW PROFILE 

D2.9NP (and POST INSULATORS) 

 

D2.91 (DC-C2-1) DOUBLE SUPPORT ON CROSSARMS 

 

D2.91L DOUBLE SUPPORT ON CROSSARMS 

 (LARGE CONDUCTORS) 

 

D2.91P DOUBLE SUPPORT ON CROSSARMS 

 (POST INSULATORS) 

 

D3.1G SUSPENSION ANGLE GUIDE 

 

D4.1G DEADEND ANGLE GUIDE 

 

D5.91G THREE PHASE TAP GUIDE 

 

D6.91 (DC-C8) DOUBLE DEADENDS ON CROSSARMS 

 (FEEDTHROUGH) 

 















INDEX E 

GUYING ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

E1.1 (E1-2) SINGLE DOWN GUY (THROUGH BOLT TYPE) 

 

E1.1L (E1-3) SINGLE DOWN GUY - HEAVY DUTY 

 (THROUGH BOLT TYPE) 

 

E1.2 (E3-3) SINGLE DOWN GUY (WRAPPED TYPE) 

 

E1.3L SINGLE DOWN GUY - LARGE CONDUCTORS 

 (POLE BAND TYPE) 

 

E1.4 (E2-2) SINGLE OVERHEAD GUY - (THROUGH BOLT TYPE) 

 

E1.4L (E2-3) SINGLE OVERHEAD GUY - HEAVY DUTY 

 (THROUGH BOLT TYPE) 

 

E1.5 GUY STRAIN INSULATOR 

 

E2.1G DOUBLE DOWN GUY GUIDE - (THROUGH BOLT TYPE) 

 

E3.1LG THREE DOWN GUY GUIDE - HEAVY DUTY 

 (THROUGH BOLT TYPE) 

 

E4.3LG FOUR DOWN GUY GUIDE - LARGE CONDUCTORS 

 (POLE BAND TYPES) 

 

 
Bulletin 1728F-804 

Section E 

Page 1 

CONSTRUCTION SPECIFICATIONS FOR GUYS

The design engineer shall determine the number and type of guys needed to be installed. 

Guys shall be attached to the pole as shown in the construction drawings and shall be 

installed before conductors are strung. Deadend structure guys shall be installed, as 

nearly as practicable, in line with the pull of conductors. Guys that bisect line angles 

(bisector guys) at line angle structures shall be installed as nearly as practicable to the 

true bisector of the line angle. 

The distance from the pole to the anchor rod (the guy lead) is recommended to be the 

same distance as from the ground to the guy attachment on the pole. This 1:1 guy slope 

is especially recommended on deadend structures. 

Written permission from RUS is required prior to the installation of sidewalk guys and 

push poles. RUS will consider the use of sidewalk guys and push poles on a case-by-case 

basis. 

The NESC requires that the grade of construction of guys be the same or higher as the 

grade of construction of: (1) the pole or structure to which they are attached, or (2) the 

highest grade required for any conductors supported by the pole or structure. 

The permitted loads shown in the design parameters for guying assemblies have already 

been calculated by RUS by multiplying a strength factor of 0.85 to the RUS designated 

loading (or strength) of the guying assemblies. The strength factor of 0.85 was used by 

RUS as an additional safety factor and is based on the spirit of the rules of NESC 

Section 261 and NESC Table 261-1A. 

The permitted loads shown on the guy assembly drawings shall be reduced by 25 percent 

for NESC Grade B construction. 

The permitted loads on guy wires shall be determined by multiplying the rated breaking 

strength of the guy wire by the strength factor of 0.90 given in NESC Table261-1A. 

Guy strength that must be provided is determined by totaling all loads expected to be 

exerting tension on the guy assembly and guy wire(s) and multiplying this total load by 

the appropriate overload factors according to NESC Rule 253 and as shown in NESC 

Table 253-1. 
Bulletin 1728F-804 

Section E 

Page 2 

CONSTRUCTION SPECIFICATIONS FOR GUYS (cont.)

If the separation on the pole between any guy attachment bolt or hardware and any phase 

conductor attachment bolt is less than 15 inches, then a guy strain insulator assembly 

(E5.1) shall be installed at the top of the guy and the guy wire shall be effectively 

grounded below the insulator by bonding the guy wire to the system neutral and the pole 

ground if present. Alternatively, an insulated extension link (item “eu”) shall be installed 

in the primary conductor tap, deadend, or suspension angle subassembly where it attaches 

to the pole. 

The purpose of this specification is to maintain minimum basic insulation impulse levels 

(BIL) and to increase clearances for line workers. 

Down guy and overhead guy wires shall be effectively grounded in accordance with Rule 

215C2 of the NESC and in accordance with the RUS assembly drawings. Effectively 

grounded guy wires provide a direct path to ground and thus decrease the chances of 

electric shock, serious injury and even death to a person standing on the ground and 

making contact with a guy wire that has accidentally become energized by means of 

contact with a primary, secondary, service or neutral conductor. Furthermore, effectively 

grounded guy wires bonded to anchor rods decrease the overall system impedance to 

ground and improve the chances of primary overcurrent protection devices to operate as 

designed. 

Down guy and overhead guy wires may be insulated in portions of a borrower’s service 

area if all 5 of the following conditions are met: 

(1) The borrower: (1) has records documenting that anchors or anchor rods have 

failed due to corrosion after less than 20 years of service, or (2) has performed 

and documented a study that has determined that insulating down guy wires is an 

adequate and economical method to mitigate predicted premature corrosion of 

anchors and anchor rods in the service area covered by the study. Such studies or 

records shall be made available for RUS review upon request; 

(2) Insulated down guys and their component parts shall be in compliance with all of 

the applicable rules of the NESC; 

(3) Only fiberglass guy strain insulators (item “w”) shall be used to insulate guy 

wires and the insulators shall be installed at the top of the guy wire as depicted in 

assembly drawing E1.5; 

(4) RUS required bonding clamps are securely installed between the anchor rod and 

the guy wire attached to the anchor rod; and 

(5) The borrower has a special regimented maintenance program in place that 

periodically (as experience indicates) checks the insulation integrity of installed 

guy insulators. 
Bulletin 1728F-804 

Section E 

Page 3 

CONSTRUCTION SPECIFICATIONS FOR GUYS (cont.)

Down guys installed on tangent, double deadend assemblies (e.g., A6.1) shall have a 

minimum clearance to the neutral conductor of 6 inches and shall have a guy strain 

insulator(s) installed at the top of the guy that extends from the pole attachment to at least 

12 inches past the neutral conductor.1 Alternatively, two down guys without guy strain 

insulators may be installed, one on each side of the neutral, such that clearance between 

each down guy wire and the neutral conductor is a minimum of 12 inches. For either of 

the above designs, the down guy wire shall be effectively bonded to ground in 

accordance with RUS specifications and the rules of the NESC. 

 

1

 For example, the 6-inch clearance can be met for a down guy with a 30-foot guy lead that is attached to 

the pole 30 feet above the ground and 2.5 feet above the neutral by installing (offsetting) the guy anchor 

6 feet perpendicular to the line of the neutral conductor. 










INDEX F 

ANCHOR ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

F1.6 (F1-1) EXPANDING TYPE ANCHORS 

F1.8 (F1-2) 

F1.10 (F1-3) 

F1.12 (F1-4) 

 

F2.6 (F1-1S) SCREW ANCHORS (POWER INSTALLED) 

F2.8 (F1-2S) 

F2.10 (F1-3S) 

F2.12 (F1-4S) 

 

F3.6 (F1-1P) PLATE TYPE ANCHORS 

F3.8 (F1-2P) 

F3.10 (F1-3P) 

F3.12 (F1-4P) 

 

F4.1 (F4-1E) SERVICE ANCHORS 

F4.2 (F4.1S) 

 

F5.1 (F5-1) ROCK ANCHORS 

F5.2 (F5-2) 

F5.3 (F5-3) 

 

F6.6 (F6-1) SWAMP ANCHORS (POWER INSTALLED) 

F6.8 (F6-2) 

F6.10 (F6-3) 

 
Bulletin 1728F-804 

Section F

CONSTRUCTION SPECIFICATIONS FOR ANCHORING 

As much as practicable, anchors and rods shall be installed in line with, and in the opposite 

direction of, the resultant strain of the conductors. Anchor assemblies shall be installed so that 

approximately 6 inches of the rod remains out of the ground. In cultivated fields or other 

locations as deemed necessary, the projection of the anchor rod above earth may be increased to 

a maximum of 12 inches to prevent burial of the rod eye. 

The backfill of all anchor holes must be thoroughly tamped the full depth. After a cone anchor 

has been set in place, the hole shall be backfilled with coarse crushed rock for 2 feet above the 

anchor and tamped during the filling. The remainder of the hole shall be backfilled and tamped 

with dirt. 

The designated holding powers shown on the anchor assembly drawings are based on the 

maximum holding power of average, Class 5 soil. When the anchor is installed in poorer soils, 

the holding power of the anchor shall be derated. A suggested guide is to derate by 25 percent in 

Class 6 soil and by 50 percent in Class 7 soil. For Class 8 soil it is usually necessary to use 

swamp anchors or power driven screw anchors which can penetrate the poor soil into firmer soil. 

See the “Soil Classifications” table on the following page for soil classes. 

Log type anchors are acceptable for use on distribution systems. Refer to the appropriate 

drawings in RUS Bulletin 1728F-811,“Electric Transmission Specifications and Drawings, 

115 kV through 230 kV” for assembly units and construction details. 
Bulletin 1728F-804 

Section F 

SOIL CLASSIFICATIONS 

Class Engineering Description

 

0 Sound hard rock, unweatherd 

 

1 Very dense and/or cemented sands; 

coarse gravel and cobbles 

 

2 Dense fine sand; very hard silts and 

clays (may be preloaded) 

 

3 Dense clayed sand and gravel; 

very stiff to hard silts and clays 

 

4 Medium dense sandy gravel; very stiff 

to hard silts and clays 

 

5 Medium dense coarse sand and sandy gravels; 

stiff to very stiff silts and clays 

 

6 Loose to medium dense fine to coarse sand; 

firm to stiff clays and silts 

 

7 Loose fine sand; alluvium; loess; 

soft-firm clays; varved clays; fill 

 

8 Peat; organic silts; inundated silts; fly ash 






INDEX G 

TRANSFORMER ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

G1.1G (M27-1A) TRANSFORMER INSTALLATION GUIDE 

 SINGLE -PHASE, POLE-TYPE TRANSFORMER 

 

G1.2G POLE TYPE TRANSFORMER LOCATION GUIDE 

 

G1.2 (G105- ) 

(G136- ) 

SINGLE-PHASE, CSP TRANSFORMER (TANGENT POLE) 

 

G1.3 (G106- ) SINGLE-PHASE, CSP TRANSFORMER (DEADEND POLE) 

 

G1.4 

G1.5 

 SINGLE-PHASE, CONVENTIONAL TRANSFORMER 

 (TANGENT POLE) 

 

G1.6 SINGLE-PHASE, CONVENTIONAL TRANSFORMER 

 (DEADEND POLE) 

 

G1.7 (G9- ) 

(G39- ) 

SINGLE-PHASE, CONVENTIONAL TRANSFORMER 

 (TANGENT POLE) 

 

G1.8 (G10- ) SINGLE-PHASE, CONVENTIONAL TRANSFORMER 

 (DEADEND POLE) 

 

G2.1 (G210- ) TWO-PHASE TRANSFORMER BANK 

OPEN-WYE PRIMARY 

OPEN-DELTA, 4 WIRE SECONDARY 

 

G2.1G TRANSFORMER / METER CONNECTION GUIDE 

THREE-PHASE, OPEN-WYE - OPEN DELTA 

FOR 120/240 VOLT POWER LOADS 

 

G3.1 (G310- ) THREE-PHASE TRANSFORMER BANK 

UNGROUNDED-WYE PRIMARY 

CENTER-TAP GROUNDED DELTA, 4 WIRE SECONDARY 

 

G3.1G TRANSFORMER / METER CONNECTION GUIDE 

UNGROUNDED WYE - CENTER TAP GROUNDED DELTA 

FOR 120/240 VOLT POWER LOADS 
INDEX G 

(Page 2) 

TRANSFORMER ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

G3.2 (G311- ) THREE-PHASE TRANSFORMER BANK 

UNGROUNDED WYE - PRIMARY 

CORNER GROUNDED DELTA, 3 WIRE SECONDARY 

 

G3.2G TRANSFORMER / METER CONNECTION GUIDE 

UNGROUNDED WYE - CORNER GROUNDED DELTA 

FOR 240 OR 480 VOLT POWER LOADS 

 

G3.3 (G312- ) THREE-PHASE TRANSFORMER BANK 

GROUNDED-WYE PRIMARY 

GROUNDED WYE, 4 WIRE SECONDARY 

 

G3.3G TRANSFORMER / METER CONNECTION GUIDE 

GROUNDED WYE - GROUNDED WYE 

FOR 120/208 VOLT POWER LOADS 
Bulletin 1728F-804 

Section G 

CONSTRUCTION SPECIFICATIONS FOR TRANSFORMERS 

It may be necessary, and it is permissible, to lower the neutral attachment on standard 

single-phase conventional type transformer assemblies an additional distance not 

exceeding 2 feet to provide adequate clearances for cutouts. 

Where applicable, the external gap on surge arresters shall be set according to the 

manufacturer’s recommended spacing. 

The construction drawings for three-phase transformer banks (e.g., “G3.1”) show cutouts 

(items “af”) and arresters (items “ae) mounted adjacent to one another on the crossarm. 

However, a cutout and arrester, as shown, may be replaced with a combination 

cutout/arrester (item “ax”). This change will require a change in the assembly’s material 

shown on the construction drawings. Moreover, the arresters may be mounted directly on 

the transformer tank. (The cutouts remain on the arm.) Any of the above mounting 

arrangements for three-phase transformer banks are acceptable; the choice is left to the 

design engineer. 

The construction drawings for single-phase conventional transformer assemblies show 

surge arresters mounted directly on the transformer tank which maximizes transformer 

surge protection. Except for single-phase conventional transformers with open link fused 

cutouts (assemblies “G1.7” and “G1.8”), the arrester may be mounted on a crossarm, on a 

bracket (item “fn”) adjacent to the cutout, or a combination cutout/arrester (item “ax”) 

may be used. The choice of using any of these acceptable mounting arrangements is left 

to the design engineer. 

Tank-mounted arresters provide maximum surge protection to transformers because of 

the arresters’ minimum lead lengths. However, when arresters are mounted directly on 

transformer tanks, the fused cutouts have less surge protection and are subject to more 

frequent operations. Nuisance operations on fused cutouts with minimal surge protection 

can be lessened with the use of dual-element fuses. 

The wiring schematics on the three-phase transformer/meter connection guide drawings 

(e.g., “G3.1G”) are based on single-phase transformers with additive polarity. ANSI 

Standard C57-12.20 specifies that all single-phase transformers larger than 200 kVA have 

subtractive polarity. If the transformer/meter connection guides are used for single-phase 

transformers larger than 200 kVA, the schematic diagrams will need to be modified 

accordingly. 

 
















 INDEX H 

GROUNDING ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

H1.1 (M2-11) GROUNDING ASSEMBLY - GROUND ROD TYPE 

 

H2.1 (M2-13) GROUNDING ASSEMBLY - TRENCH TYPE 

 

H3.1 (M2-15) GROUNDING ASSEMBLY - GROUND ROD TYPE 

 (FOR SECTIONALIZING AIRBREAK SWITCH) 

 

H4.1 (M2-15A) GROUNDING ASSEMBLY - PLATFORM TYPE 

 (FOR SECTIONALIZING AIRBREAK SWITCH) 

 

H5.1 (M2-12) GROUNDING IMPROVEMENT ASSEMBLY – PLATE TYPE 

 

H5.2 

H5.3 

(M2-12A) GROUNDING IMPROVEMENT ASSEMBLY – 

 WRAP-AROUND TYPE 

 
Bulletin 1728F-804 

Section H

CONSTRUCTION SPECIFICATIONS FOR GROUNDING 

Ground rods (item “ai”) shall be driven to their full length in undisturbed earth, a 

minimum of 2 feet from the face of the pole. The tops of the ground rods shall be at least 

12 inches below the surface of the earth. The ground wire (item “av”) shall be attached 

to the rod with a ground rod clamp (item “aj”) and shall be secured to the pole with 

staples. The staples on the ground wire shall be spaced 2 feet part, except for the first 8 

feet above the ground and the top 8 feet of the ground wire where they shall be spaced 

6 inches apart. 

The connection between the ground rod and the system neutral should be made by one 

continuous piece of conductor (the pole ground wire), and shall be installed in the 

shortest and most direct path according to the construction drawings. Splices, if required, 

shall be made using a compression type connector and shall be installed a minimum of 6 

inches above the ground line. The pole ground wire shall be connected to the system 

neutral using a compression type connector. 

All equipment shall have at least 2 connections from the frame, case, or tank to the multigrounded system neutral conductor as shown on the construction drawings. The pole 

ground wire may be used for one or both of these connections. 

All neutral conductors on the pole shall be bonded directly to each other, and connected 

to the pole ground wire if present. All equipment ground wires, neutral conductors, 

downguys, messenger wires, and surge-protection ground wires shall be interconnected 

and attached to a common (pole) ground wire in accordance with the requirements of the 

National Electrical Safety Code (NESC). 

Borrowers shall install effectively grounded driven ground rods (assembly H1.1) or 

trench type grounding assemblies (assembly H2.1) a maximum of 1,320 feet (433 meters) 

apart along overhead distribution lines. Customer-owned or other installed electric 

service grounds shall not be counted in the above minimum grounding assembly 

requirement. 

Whereas under certain circumstances, plate type and wrap-around type grounding 

improvement assemblies (assemblies H5.1 and H5.2, respectively) may meet the 

grounding electrode requirements of Rule 094B4 of the NESC, RUS does not allow these 

types of grounding assemblies to be used to meet the NESC requirement of 4 grounds per 

mile because the effectiveness of these types of grounds in “disturbed” earth is often 

questionable. However, RUS encourages the installation of these grounding 

improvement assemblies to augment and improve the overall grounding of the 

distribution system that in turn generally improves the performance of line protection 

devices and improves safety. 






INDEX J 

SECONDARY ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

J1.1 (J8) SECONDARY ASSEMBLIES - (SMALL ANGLE) 

J1.2 (J5) 

 

J2.1 (J10) SECONDARY ASSEMBLIES - (LARGE ANGLE) 

J2.2 (J7), (J7C) 

 

J3.1 (J6), (J11) SECONDARY ASSEMBLIES - (DEADEND, MISC.) 

J4.1 (J12) 

 
Bulletin 1728F-804 

Section J 

CONSTRUCTION R SECONDARY CONDUCTORS 

 AND SERVICE DROPS 

Secondary conductors may be bare or covered wires or multi-conductor service cable. 

mmendations. 

xcept in those 

here conditions may necessitate that covered wires or service cable be 

cordance with 

mbing space on 

struction there shall not be more than one splice per 

conductor in any span, and splices shall be located at least 10 feet from the conductor 

y and service 

The “permitted longitudinal loadings” shown on the assembly drawings are based on 

50 percent of the mechanical-electrical ratings of the insulators. All applied loads must 

be multiplied by the appropriate NESC overload factors when applicable. 

 SPECIFICATIONS FO

The conductors shall be sagged in accordance with the manufacturer’s reco

Conductors for secondary underbuild on primary lines may be bare wires, e

circumstances w

used. Service drop conductors shall be covered wires or service cable in ac

NESC Rule 234C3. 

Secondary and service drop conductors shall be installed such that the cli

poles is not obstructed. For new con

support. Covered conductors or service cables used for both the secondar

drop may be installed in one continuous run. 



INDEX K 

SERVICE ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

K1.1 (K14C) SECRVICE ASSEMBLIES - (POLE MOUNTED)

K1.2 (K11C) 

K1.3 (K14), (K14L) 

 

K1.4 (K11), (K11L) SECRVICE ASSEMBLIES - (POLE MOUNTED) 

K1.5 (K15C) 

 

K2.1 (K10), (K10L) SERVICE ASSEMBLIES 

K2.2 (K10C) 

K2.3 (K10C) 

 

K3.1 (K17), (K17L) SERVICE ASSEMBLIES - (MAST TYPE) 

K3.2 (K16C) 

 

K4.1G (M24) CABLE SERVICE ASSEMBLY GUIDE 

 

K4.2G (M24-10) MAST TYPE SERVICE ASSEMBLY GUIDE 

 






INDEX L 

TYING ASSEMBLIES 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

L1.1 

L1.2 

(M41-1) 

(M41-10) 

PRIMARY ANGLE TYING ASSEMBLIES 

 

L1.3 

L1.4 

L1.5 

(M42-3) 

(M42-21) 

(M42-11) 

PRIMARY DEADEND TYING ASSEMBLIES 

 

L2.1 

L2.2 

 NEUTRAL ANGLE TYING ASSEMBLIES 

 

L2.3 

L2.4 

L2.5 (M42-13) 

NEUTRAL DEADEND TYING ASSEMBLIES 

 

L3.1 

L3.2 

(M41-1) 

(M41-10) 

NEUTRAL & SECONDARY ANGLE TYING ASSEMBLIES 

 

L3.3 

L3.4 

(M42-21) 

(M42-3) 

NEUTRAL & SECONDARY DEADEND TYING ASSEMBLIES - 

(COPPER) 

 

L3.5 

L3.6 

(M42-11) NEUTRAL & SECONDARY DEADEND TYING ASSEMBLIES - 

(ACSR) 

 

L4.1 TYING ASSEMBLIES, SERVICES 

 

L4.2 

L4.3 

L4.4 

 TYING ASSEMBLIES, CABLE SERVICES 

 
Bulletin 1728F-804 

Section L 

CONSTRUCTION SPECIFICATIONS FOR CONNECTORS, STIRRUPS, 

 CLAMPS, TAPS, AND JUMPERS 

Jumpers and other leads connected to line conductors shall have sufficient slack to allow free 

movement of the conductors without causing the jumpers to be pulled from their connectors. 

Even if not shown on the drawings, jumpers shall have at least two bends in a vertical plane, or 

one in a horizontal plane, or the equivalent. 

 

All leads on equipment, such as transformers and reclosers, shall be a minimum of #6 copper 

conductivity. Where aluminum jumpers are used, a connection to unplated bronze terminals 

shall be made by splicing a short stub of copper to the aluminum jumpers using a compression 

connector suitable for the bimetallic connection. 

Connectors and hot-line clamps suitable for the purpose shall be installed as shown on the 

drawings and also in accordance with the manufacturer's specifications and recommendations. 

On all hot-line clamp installations, the clamp and jumper shall be installed so that they are 

permanently bonded to the load side of the line, allowing the jumper to be de-energized when the 

clamp is disconnected. 

Stirrups may be used to connect tap conductors (jumper wires) to primary conductors if the 

following criteria are met: 

• The stirrup and hot line clamp are sized to meet or exceed the current carrying capacity of the 

tap conductor or equipment jumper; 

• All stirrup conductors are made of copper or bronze; 

• All stirrup conductors are made of #2 copper equivalent conductivity or larger; 

• All-purpose or aluminum hot line clamps are not used with stirrups; 

• All stirrups, connectors, and clamps are installed in accordance with the manufacturer’s 

specifications; 

• Stirrups with two compression connectors are not used in areas prone to aeolian vibration; 

• Stirrups are not used to connect main lines together or to connect heavily loaded tap lines to 

main lines. 

Stirrups are not recommended to be used to connect reclosers, autotransformers, or line 

regulators to primary conductors. Stirrups and hot line clamps shall not be used for 

sectionalizing taps nor taps for main lines for operational or maintenance purposes. Permanent 

compression or bolted type connectors shall be used because of their better current carrying 

capabilities and reliability. Line switches, fused cutouts, or solid blade cutouts should be used at 

line locations where occasional line sectionalizing may be required. 

At locations where permanent connections using compression or bolted type connectors are not 

desired, and where the installation of sectionalizing equipment is also not desired, hot line 

clamps (over armor rod on aluminum conductors) shall be installed. 









INDEX M 

MISCELLANEOUS ASSEMBLY UNITS AND GUIDES 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

M1.30G (R1) RIGHT-OF-WAY CLEARING GUIDE 

 
Bulletin 1728F-804 

Section M 

SPECIFICATIONS FOR RIGHT-OF-WAY CLEARING 

The right-of-way shall be prepared by removing trees, clearing underbrush, and trimming 

trees so that the right-of-way is cleared close to the ground and to the width specified. 

However, low growing shrubs, which will not interfere with the operation or maintenance 

of the line, can be left undisturbed if so directed by the property owner. Slash may be 

chipped and blown on the right-of-way if so allowed. Trim, but do not remove shade, 

fruit, or ornamental trees unless otherwise authorized. 

All trimming shall be done using good arboricultural practices. 

The landowner’s written permission is usually required prior to cutting trees outside of 

the right-of-way. Trim trees fronting each side of the right-of-way symmetrically unless 

otherwise specified. Remove dead trees beyond the right-of-way which would strike the 

line in falling. Also, either remove or top leaning trees beyond the right-of-way that 

would strike the line in falling. 

INDEX N 

NEUTRAL ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

N1.1 NEUTRAL ASSEMBLIES - TANGENT 

N1.2 (M5-19) 

 

N1.11 NEUTRAL SUPPORTS ON CROSSARMS 

N2.21 

 

N2.1 NEUTRAL ASSEMBLIES - LARGE ANGLE 

N2.1L 

 

N5.1 (M5-25) NEUTRAL ASSEMBLIES - (SINGLE DEADENDS) 

N5.2 

N5.3 (M5-26) 

 

N6.1 NEUTRAL ASSEMBLY - DOUBLE DEADEND 

 

N6.21 NEUTRAL ASSEMBLY - DOUBLE DEADEND ON CROSSARMS 

 






INDEX P 

PROTECTION ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

P1.01 (M5-6) SURGE ARRESTERS - SINGLE PHASE 

P1.1 

 

P1.1NG SURGE ARRESTER GUIDE - NARROW PROFILE 

 

P1.3 SURGE ARRESTERS - 3 SINGLE PHASE 

 

P3.1G RAPTOR PROTECTION ASSEMBLY GUIDE 

 SUPPORT ON 8-FOOT CROSSARMS (TANGENT) 

 

P3.2G RAPTOR PROTECTION ASSEMBLY GUIDE 

 SUPPORT ON 10-FOOT CROSSARMS (TANGENT) 

 

P3.3G RAPTOR PROTECTION, PERCH GUARDS - GUIDE 

 

P3.4G RAPTOR PROTECTION, SINGLE-PHASE, CSP TRANSFORMER 

 (TANGENT POLE) 

 

P3.5G RAPTOR PROTECTION ASSEMBLY GUIDE 

 THREE-PHASE TRANSFORMER BANK 

 
Bulletin 1728F-804 

Section P

CONSTRUCTION SPECIFICATIONS FOR RAPTOR PROTECTION 

Raptor injury and electrocution around power lines are major wildlife concerns of the 

U.S. Fish and Wildlife Service. Raptors are protected by the Endangered Species Act, 

the Eagle Protection Act, and the Migratory Bird Treaty Act. The electrocution issue 

may be a problem especially on lines with voltages of 69 kV or less. Reports indicate 

that raptor concerns exist primarily on distribution lines in western and southwestern 

states; however, hazards can exist anywhere in the United States where large birds are 

present. 

The provisions included on the “P3” series of construction drawings will help to 

minimize or eliminate bird electrocutions. This construction should be used in areas 

where raptors or other large birds are present. It may be prudent to adopt these designs 

for all new construction. 








INDEX Q 

METERING ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

Q1.1 (M8) SECONDARY METERING - SINGLE-PHASE, 120/240 VOLTS 

 

Q2.1G (M8-10) POLE TYPE SERVICE ASSEMBLY GUIDE 

 

Q2.2G (M8-9) YARD POLE METER INSTALLATION GUIDE 

 

Q3.1 (M8-6) SECONDARY METERING - THREE-PHASE, 120/240 VOLTS 

 (4 WIRE DELTA) 

 

Q3.2 (M8-12) SECONDARY METERING - THREE-PHASE, 240 OR 480 VOLTS 

 (3 WIRE CORNER GROUNDED DELTA) 

 

Q3.3 (M8-11) SECONDARY METERING - THREE-PHASE, 120/208 VOLTS 

 (4 WIRE GROUNDED WYE) 

 

Q4.1 (M8-15) PRIMARY METERING, THREE-PHASE 

 (4 WIRE GROUNDED WYE) 

 







INDEX R 

OIL CIRCUIT RECLOSER ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

R1.1 (M3-10) OIL CIRCUIT RECLOSER 

 

R1.2 (M3-23A) OIL CIRCUIT RECLOSER - (WITH BYPASS CUTOUT) 

 

R2.1 (M3-11A) (THREE) OIL CIRCUIT RECLOSERS 

R3.1 (M3-12A) 

 

R2.2 (M3-24A) (THREE) OIL CIRCUIT RECLOSERS 

R3.2 (M3-25A) (WITH BYPASS SWITCHES) 

 

R3.3 (M3-30) THREE-PHASE OIL CIRCUIT RECLOSER WITH BY-PASS 

SWITCHES 





INDEX S 

SECTIONALIZING ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

S1.01 (M5-9) MISCELLANEOUS CUTOUTS AND DISCONNECT SWITCH 

S1.02 (M5-10) 

S2.01 

 

S1.1 (M3-4) CUTOUT - SINGLE PHASE 

 

S1.1N CUTOUT GUIDE - NARROW PROFILE 

 

S1.3 COUTOUTS - (THREE SINGLE-PHASE) 

 

S2.3 (M3-3B) LINE TENSION SWITCHES – (THREE SINGLE-PHASE) 

 

S2.21 (M3-2A) DISCONNECT SWITCHES - (TWO OR THREE SINGLE-PHASE) 

S2.31 (M3-3A) 

 

S2.32 (M3-15) GROUP-OPERATED AIRBREAK SWITCH - (THREE-PHASE) 

 

S3.1 (M3-41) SECTIONALIZER 

 

S3.2 SECTIONALIZER (WITH BYPASS CUTOUT) 









INDEX W 

WOOD POLES, CROSSARMS AND BRACES 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

W1.1G (M20) POLE FRAMING GUIDE 

 

W2.1G (M19) DISTRIBUTION CROSSARM DRILLING GUIDE 

 

W3.1 (M5-17) CROSSARM BRACES 

W3.2 (M5-13) 

 
Bulletin 1728F-804 

Section W 

CONSTRUCTION SPECIFICATIONS FOR POLES AND CROSSARMS 

Large, dense poles that have no serious defects shall be used at transformer, deadend, 

angle, and corner locations. 

Poles shall be set so that the crossarm gains face in opposite directions on every other 

pole. However at line deadends, the last two poles shall be set so that the pole gains face 

the deadend. On unusually long spans, the poles shall be set so that the crossarm is 

located on the side of the pole away from the long span. On lines that curve, the 

crossarms shall be installed on the side of the pole that faces the midpoint of the curve. 

On sloping terrain, the crossarms shall be installed on the uphill side of the pole. Pole top 

insulator brackets and pole top pins shall be installed on the opposite side of the pole 

from the gain. 

At line angles and deadends, poles shall be set such that they lean away from the strain of 

the primary conductors. They shall be set such that the final rake is not less than 1 inch 

for each 10 feet of pole height above ground after the conductors are installed at the 

required tension. 

Newly set poles shall be backfilled and tamped to the full depth. Excess dirt shall be 

banked around the base of the pole. 
Bulletin 1728F-804 

Section W 

POLE SETTING DEPTHS 

The minimum depth for setting poles is: 

Length of Pole 

 (Feet) 

Setting in Soil 

 (Feet) 

Setting in All Solid Rock 

(Feet) 

20 4.0 3.0 

25 5.0 3.5 

30 5.5 3.5 

35 6.0 4.0 

40 6.0 4.0 

45 6.5 4.5 

50 7.0 4.5 

55 7.5 5.0 

60 8.0 5.0 

“Setting in Soil” depths apply where: 

• Poles are set in soil; 

• There is a layer of soil of more than two (2) feet in depth over solid rock; or 

• The hole in solid rock is not substantially vertical or the diameter of the hole at the 

surface of the rock exceeds approximately twice the diameter of the pole at the same 

level. 

“Setting in All Solid Rock” depths shall apply where poles are set in solid rock and where 

the hole is substantially vertical, approximately uniform in diameter and large enough to 

permit the use of tamping bars the full depth of the hole. 

Where there is a layer of soil two (2) feet or less in depth over solid rock, the depth of the 

hole shall be the depth of the soil in addition to the depth specified under “Setting in All 

Solid Rock” provided. However, this depth shall not exceed the depth specified under 

“Setting in Soil.” 

On sloping ground, the depth of the hole shall be measured from the low side of the hole. 



INDEX Y 

VOLTAGE ALTERATION EQUIPMENT ASSEMBLY UNITS 

DRAWING NUMBERS DRAWING TITLE (DESCRIPTION)

1728F-804 

 (New) 

Bulletin 50-3 

(Old) 

 

Y1.1 (M7-11) VOLTAGE REGULATOR, POLE MOUNTED 

 (ONE SINGLE-PHASE) 

 

Y1.3 (M7-13) VOLTAGE REGULATOR, PLATFORM MOUNTED 

 (THREE SINGLE-PHASE) 

 

Y2.1 AUTOTRANSFORMER, POLE MOUNTED 

Y2.2 (ONE SINGLE-PHASE, STEP-DOWN) 

 

Y3.1 (M9-11) SINGLE-PHASE CAPACITOR BANK 

 

Y3.2 (M9-12) THREE-PHASE CAPACITOR BANK 

Y3.3 (M9-13) 

 

Y3.4 SWITCHED CAPACITOR BANK - THREE-PHASE 

 






Bulletin 1728F-804 

Exhibit 1 

Page 1 

Calculation of Maximum Line Angles 

The following formula and the data tabulated below were used to calculate the maximum 

line angles on pin and spool insulator assemblies: 

Where: 

θ = Maximum Line Angle (calculated): [Degrees] 

P = Designated Maximum Transverse Load (allowed on pin or insulator): [lbs] 

Fw = Wind Overload Factor for Transverse Loads 

Ft = Wire Tension Overload Factor for Transverse Loads 

Sw = Wind Span (equals 1⁄2 sum of adjacent spans): [ft] 

Ww = Wind Load on Conductor: [lbs/ft] (See Table Below)

T = Design Tension of Conductor: [lbs] (See Table Below)

From NESC Table 253-1 for Grade C Construction: 

Fw = 1.75 for non-crossing spans (Footnote 4 to Table 253-1) 

 = 2.20 for crossing spans 

Ft = 1.30 

CONDUCTOR Maximum Design 

SIZE & TYPE Strength Tension Tension (T)(lbs)

4 ACSR (7/1) 2360 60% 1416 

2 ACSR (6/1) 2850 60% 1710 

2 ACSR (7/1) 3640 60% 2184 

1/0 ACSR (6/1) 4380 60% 2628 

123.3 AAC (7) 4460 60% 2676 

2/0 ACSR (6/1) 5310 50% 2655 

3/0 ACSR (6/1) 6620 50% 3310 

4/0 ACSR (6/1) 8350 40% 3340 

246.9 AAC (7) 8560 40% 3424 

336.4 ACSR (18/1) 8680 40% 3472 

336.4 ACSR (26/7) 14100 35% 4935 

WIND LOAD (Ww) (lbs/ft) by NESC Loading District

LIGHT MEDIUM HEAVY

4 ACSR (7/1) 0.1928 0.2523 0.4190 

2 ACSR (6/1) 0.2370 0.2720 0.4387 

2 ACSR (7/1) 0.2438 0.2750 0.4417 

1/0 ACSR (6/1) 0.2985 0.2993 0.4660 

123.3 AAC (7) 0.2985 0.2993 0.4660 

2/0 ACSR (6/1) 0.3353 0.3157 0.4823 

3/0 ACSR (6/1) 0.3765 0.3340 0.5007 

4/0 ACSR (6/1) 0.4223 0.3543 0.5210 

246.9 AAC (7) 0.4223 0.3543 0.5210 

336.4 ACSR (18/1) 0.5130 0.3947 0.5613 

336.4 ACSR (26/7) 0.5408 0.4070 0.5737 

Ft T

P Fw Sw Ww Sin

× ×

− × ×

=

2

( )

(θ )2/













× ×

− × ×

= ×

Ft T

P Fw Sw Ww Arc

2

( )

θ 2 sin
Bulletin 1728F-804

Exhibit 1

Page 2 

TABLE I

Designated Maximum Transverse Load = 500 Lbs./Conductor

WIND SPAN (feet) 150 200 250 300 350 400

CONDUCTOR SIZE LIGHT LOADING DISTRICT

4 ACSR (7/1) 14 13 13 12 12 11

2 ACSR (6/1) 11 11 10 10 9 9

2 ACSR (7/1) 9 8 8 8 7 7

1/0 ACSR (6/1) 7 7 6 6 5 5

123.3 AAAC (7) 7 7 6 6 5 5

2/0 ACSR (6/1) 7 6 6 5 5 4

3/0 ACSR (6/1) 5 5 4 4 4 3

4/0 ACSR (6/1) 5 5 4 4 3 3

246.9 AAAC (7) 5 5 4 4 3 3

336.4 ACSR (18/1) 5 4 3 3 2 2

336.4 ACSR (26/7) 3 3 2 2 2 1

MEDIUM LOADING DISTRICT

4 ACSR (7/1) 14 13 12 11 11 10

2 ACSR (6/1) 11 10 10 9 9 8

2 ACSR (7/1) 9 8 8 7 7 6

1/0 ACSR (6/1) 7 7 6 6 5 5

123.3 AAAC (7) 7 7 6 6 5 5

2/0 ACSR (6/1) 7 6 6 6 5 5

3/0 ACSR (6/1) 5 5 5 4 4 4

4/0 ACSR (6/1) 5 5 5 4 4 3

246.9 AAAC (7) 5 5 4 4 4 3

336.4 ACSR (18/1) 5 5 4 4 3 3

336.4 ACSR (26/7) 4 3 3 3 2 2

HEAVY LOADING DISTRICT

4 ACSR (7/1) 12 11 10 9 8 6

2 ACSR (6/1) 10 9 8 7 6 5

2 ACSR (7/1) 8 7 6 5 5 4

1/0 ACSR (6/1) 6 6 5 4 4 3

123.3 AAAC (7) 6 6 5 4 4 3

2/0 ACSR (6/1) 6 6 5 4 3 3

3/0 ACSR (6/1) 5 4 4 3 3 2

4/0 ACSR (6/1) 5 4 4 3 2 2

246.9 AAAC (7) 5 4 4 3 2 2

336.4 ACSR (18/1) 4 4 3 3 2 1

336.4 ACSR (26/7) 3 3 2 2 1 1

MAXIMUM LINE ANGLES (Degrees)

Note: Decrease line angle by 1 degree for poles adjacent to a crossing span.

NESC Grade C Construction (Re-calculate for NESC Grade B)

PIN and POST TYPE INSULATOR ASSEMBLIES
Bulletin 1728F-804

Exhibit 1

Page 3

TABLE II

Designated Maximum Transverse Load = 750 Lbs./Conductor

WIND SPAN (feet) 150 200 250 300 350 400

CONDUCTOR SIZE LIGHT LOADING DISTRICT

4 ACSR (7/1) 22 21 21 20 20 19

2 ACSR (6/1) 18 17 17 16 16 15

2 ACSR (7/1) 14 13 13 13 12 12

1/0 ACSR (6/1) 11 11 10 10 10 9

123.3 AAAC (7) 11 11 10 10 9 9

2/0 ACSR (6/1) 11 11 10 10 9 9

3/0 ACSR (6/1) 988 776

4/0 ACSR (6/1) 887 766

246.9 AAAC (7) 887 766

336.4 ACSR (18/1) 877 665

336.4 ACSR (26/7) 555 443

MEDIUM LOADING DISTRICT

4 ACSR (7/1) 21 21 20 19 19 18

2 ACSR (6/1) 18 17 16 16 15 14

2 ACSR (7/1) 14 13 13 12 12 11

1/0 ACSR (6/1) 11 11 10 10 10 9

123.3 AAAC (7) 11 11 10 10 9 9

2/0 ACSR (6/1) 11 11 10 10 9 9

3/0 ACSR (6/1) 988 877

4/0 ACSR (6/1) 988 777

246.9 AAAC (7) 888 776

336.4 ACSR (18/1) 887 766

336.4 ACSR (26/7) 655 544

HEAVY LOADING DISTRICT

4 ACSR (7/1) 20 19 18 17 15 14

2 ACSR (6/1) 16 15 14 13 12 11

2 ACSR (7/1) 13 12 11 10 10 9

1/0 ACSR (6/1) 11 10 9 8 8 7

123.3 AAAC (7) 10 10 9 8 8 7

2/0 ACSR (6/1) 10 10 9 8 8 7

3/0 ACSR (6/1) 887 665

4/0 ACSR (6/1) 877 665

246.9 AAAC (7) 877 665

336.4 ACSR (18/1) 876 655

336.4 ACSR (26/7) 554 443

MAXIMUM LINE ANGLES (Degrees)

NESC Grade C Construction (Re-calculate for NESC Grade B)

Note: Decrease line angle by 1 degree for poles adjacent to a crossing span.

PIN and POST TYPE INSULATOR ASSEMBLIES
Bulletin 1728F-804

Exhibit 1

Page 4

TABLE III

Designated Maximum Transverse Load = 1,000 Lbs./Conductor

WIND SPAN (feet) 150 200 250 300 350 400

CONDUCTOR SIZE LIGHT LOADING DISTRICT

4 ACSR (7/1) 30 29 29 28 28 27

2 ACSR (6/1) 24 24 23 23 22 22

2 ACSR (7/1) 19 19 18 18 17 17

1/0 ACSR (6/1) 16 15 15 14 14 13

123.3 AAAC (7) 15 15 14 14 13 13

2/0 ACSR (6/1) 15 15 14 14 13 13

3/0 ACSR (6/1) 12 12 11 11 10 10

4/0 ACSR (6/1) 12 11 11 10 10 9

246.9 AAAC (7) 11 11 11 10 10 9

336.4 ACSR (18/1) 11 10 10 9 9 8

336.4 ACSR (26/7) 877 666

MEDIUM LOADING DISTRICT

4 ACSR (7/1) 29 29 28 27 27 26

2 ACSR (6/1) 24 23 23 22 22 21

2 ACSR (7/1) 19 18 18 17 17 16

1/0 ACSR (6/1) 16 15 15 14 14 13

123.3 AAAC (7) 15 15 14 14 13 13

2/0 ACSR (6/1) 15 15 14 14 13 13

3/0 ACSR (6/1) 12 12 11 11 11 10

4/0 ACSR (6/1) 12 12 11 11 10 10

246.9 AAAC (7) 12 11 11 10 10 10

336.4 ACSR (18/1) 11 11 11 10 10 9

336.4 ACSR (26/7) 887 776

HEAVY LOADING DISTRICT

4 ACSR (7/1) 28 27 26 24 23 22

2 ACSR (6/1) 23 22 21 20 19 18

2 ACSR (7/1) 18 17 16 16 15 14

1/0 ACSR (6/1) 15 14 13 13 12 11

123.3 AAAC (7) 14 14 13 12 12 11

2/0 ACSR (6/1) 15 14 13 12 12 11

3/0 ACSR (6/1) 12 11 10 10 9 9

4/0 ACSR (6/1) 11 11 10 10 9 8

246.9 AAAC (7) 11 11 10 9 9 8

336.4 ACSR (18/1) 11 10 10 9 8 8

336.4 ACSR (26/7) 877 665

MAXIMUM LINE ANGLES (Degrees)

NESC Grade C Construction (Re-calculate for NESC Grade B)

Note: Decrease line angle by 1 degree for poles adjacent to a crossing span.

PIN and POST TYPE INSULATOR ASSEMBLIES
Bulletin 1728F-804

Exhibit 1

Page 5

TABLE IV

Designated Maximum Transverse Load = 1,500 Lbs./Conductor

WIND SPAN (feet) 150 200 250 300 350 400

CONDUCTOR SIZE LIGHT LOADING DISTRICT

4 ACSR (7/1) 46 46 45 45 44 44

2 ACSR (6/1) 38 37 37 36 35 35

2 ACSR (7/1) 29 29 28 28 28 27

1/0 ACSR (6/1) 24 24 23 23 22 22

123.3 AAAC (7) 24 23 23 22 22 21

2/0 ACSR (6/1) 24 23 23 22 22 21

3/0 ACSR (6/1) 19 18 18 17 17 17

4/0 ACSR (6/1) 18 18 17 17 16 16

246.9 AAAC (7) 18 17 17 17 16 16

336.4 ACSR (18/1) 17 17 16 16 15 15

336.4 ACSR (26/7) 12 12 11 11 10 10

MEDIUM LOADING DISTRICT

4 ACSR (7/1) 46 45 44 44 43 42

2 ACSR (6/1) 37 37 36 36 35 34

2 ACSR (7/1) 29 29 28 28 27 27

1/0 ACSR (6/1) 24 24 23 23 22 22

123.3 AAAC (7) 24 23 23 22 22 21

2/0 ACSR (6/1) 24 23 23 22 22 21

3/0 ACSR (6/1) 19 18 18 18 17 17

4/0 ACSR (6/1) 19 18 18 17 17 17

246.9 AAAC (7) 18 18 17 17 17 16

336.4 ACSR (18/1) 18 17 17 16 16 16

336.4 ACSR (26/7) 12 12 12 12 11 11

HEAVY LOADING DISTRICT

4 ACSR (7/1) 44 43 42 41 39 38

2 ACSR (6/1) 36 35 34 33 32 31

2 ACSR (7/1) 28 27 27 26 25 24

1/0 ACSR (6/1) 23 23 22 21 20 20

123.3 AAAC (7) 23 22 21 21 20 19

2/0 ACSR (6/1) 23 22 22 21 20 19

3/0 ACSR (6/1) 18 18 17 17 16 15

4/0 ACSR (6/1) 18 17 17 16 16 15

246.9 AAAC (7) 18 17 16 16 15 15

336.4 ACSR (18/1) 17 17 16 15 15 14

336.4 ACSR (26/7) 12 12 11 11 10 10

MAXIMUM LINE ANGLES (Degrees)

NESC Grade C Construction (Re-calculate for NESC Grade B)

Note: Decrease line angle by 1 degree for poles adjacent to a crossing span.

PIN and POST TYPE INSULATOR ASSEMBLIES
Bulletin 1728F-804

Exhibit 1

Page 6

TABLE V

Designated Maximum Transverse Load = 2,000 Lbs./Conductor

WIND SPAN (feet) 150 200 250 300 350 400

CONDUCTOR SIZE LIGHT LOADING DISTRICT

4 ACSR (7/1) 60 60 60 60 60 60

2 ACSR (6/1) 52 51 50 50 49 49

2 ACSR (7/1) 40 39 39 38 38 38

1/0 ACSR (6/1) 33 32 32 31 31 30

123.3 AAAC (7) 32 32 31 31 30 30

2/0 ACSR (6/1) 32 32 31 31 30 30

3/0 ACSR (6/1) 26 25 25 24 24 23

4/0 ACSR (6/1) 25 25 24 24 23 23

246.9 AAAC (7) 25 24 24 23 23 22

336.4 ACSR (18/1) 24 23 23 22 22 21

336.4 ACSR (26/7) 17 16 16 15 15 15

MEDIUM LOADING DISTRICT

4 ACSR (7/1) 60 60 60 60 60 59

2 ACSR (6/1) 51 51 50 49 49 48

2 ACSR (7/1) 40 39 39 38 38 37

1/0 ACSR (6/1) 33 32 32 31 31 30

123.3 AAAC (7) 32 32 31 31 30 30

2/0 ACSR (6/1) 32 32 31 31 30 30

3/0 ACSR (6/1) 26 25 25 24 24 24

4/0 ACSR (6/1) 25 25 25 24 24 23

246.9 AAAC (7) 25 24 24 24 23 23

336.4 ACSR (18/1) 24 24 23 23 22 22

336.4 ACSR (26/7) 17 17 16 16 16 15

HEAVY LOADING DISTRICT

4 ACSR (7/1) 60 60 59 58 57 55

2 ACSR (6/1) 50 49 48 47 46 45

2 ACSR (7/1) 39 38 37 36 35 35

1/0 ACSR (6/1) 32 31 30 30 29 28

123.3 AAAC (7) 31 31 30 29 29 28

2/0 ACSR (6/1) 31 31 30 29 29 28

3/0 ACSR (6/1) 25 24 24 23 23 22

4/0 ACSR (6/1) 25 24 24 23 22 22

246.9 AAAC (7) 24 24 23 22 22 21

336.4 ACSR (18/1) 24 23 22 22 21 21

336.4 ACSR (26/7) 17 16 16 15 15 14

MAXIMUM LINE ANGLES (Degrees)

NESC Grade C Construction (Re-calculate for NESC Grade B)

Note: Decrease line angle by 1 degree for poles adjacent to a crossing span.

PIN and POST TYPE INSULATOR ASSEMBLIES
Bulletin 1728F-804

Exhibit 1

Page 7

TABLE VI

Designated Maximum Transverse Load = 1,500 Lbs./Conductor

WIND SPAN (feet) 150 200 250 300 350 400

CONDUCTOR SIZE LIGHT LOADING DISTRICT

4 ACSR (7/1) 46 46 45 45 44 44

2 ACSR (6/1) 38 37 37 36 35 35

2 ACSR (7/1) 29 29 28 28 28 27

1/0 ACSR (6/1) 24 24 23 23 22 22

123.3 AAAC (7) 24 23 23 22 22 21

2/0 ACSR (6/1) 24 23 23 22 22 21

3/0 ACSR (6/1) 19 18 18 17 17 17

4/0 ACSR (6/1) 18 18 17 17 16 16

246.9 AAAC (7) 18 17 17 17 16 16

336.4 ACSR (18/1) 17 17 16 16 15 15

336.4 ACSR (26/7) 12 12 11 11 10 10

MEDIUM LOADING DISTRICT

4 ACSR (7/1) 46 45 44 44 43 42

2 ACSR (6/1) 37 37 36 36 35 34

2 ACSR (7/1) 29 29 28 28 27 27

1/0 ACSR (6/1) 24 24 23 23 22 22

123.3 AAAC (7) 24 23 23 22 22 21

2/0 ACSR (6/1) 24 23 23 22 22 21

3/0 ACSR (6/1) 19 18 18 18 17 17

4/0 ACSR (6/1) 19 18 18 17 17 17

246.9 AAAC (7) 18 18 17 17 17 16

336.4 ACSR (18/1) 18 17 17 16 16 16

336.4 ACSR (26/7) 12 12 12 12 11 11

HEAVY LOADING DISTRICT

4 ACSR (7/1) 44 43 42 41 39 38

2 ACSR (6/1) 36 35 34 33 32 31

2 ACSR (7/1) 28 27 27 26 25 24

1/0 ACSR (6/1) 23 23 22 21 20 20

123.3 AAAC (7) 23 22 21 21 20 19

2/0 ACSR (6/1) 23 22 22 21 20 19

3/0 ACSR (6/1) 18 18 17 17 16 15

4/0 ACSR (6/1) 18 17 17 16 16 15

246.9 AAAC (7) 18 17 16 16 15 15

336.4 ACSR (18/1) 17 17 16 15 15 14

336.4 ACSR (26/7) 12 12 11 11 10 10

MAXIMUM LINE ANGLES (Degrees) ON SPOOL INSULATOR ASSEMBLIES

NESC Grade C Construction (Re-calculate for NESC Grade B)

Note: Decrease line angle by 1 degree for poles adjacent to a crossing span.

(ANSI Clss 53-2 Spool Insulator)
Bulletin 1728F-804

Exhibit 1

Page 8 

TABLE VII

Designated Maximum Transverse Load = 2,250 Lbs./Conductor

WIND SPAN (feet) 150 200 250 300 350 400

CONDUCTOR SIZE LIGHT LOADING DISTRICT

4 ACSR (7/1) 60 60 60 60 60 60

2 ACSR (6/1) 59 58 58 57 57 56

2 ACSR (7/1) 45 45 44 44 43 43

1/0 ACSR (6/1) 37 37 36 36 35 35

123.3 AAAC (7) 36 36 35 35 35 34

2/0 ACSR (6/1) 37 36 35 35 34 34

3/0 ACSR (6/1) 29 28 28 28 27 27

4/0 ACSR (6/1) 29 28 28 27 27 26

246.9 AAAC (7) 28 27 27 26 26 25

336.4 ACSR (18/1) 27 27 26 25 25 24

336.4 ACSR (26/7) 19 18 18 18 17 17

MEDIUM LOADING DISTRICT

4 ACSR (7/1) 60 60 60 60 60 60

2 ACSR (6/1) 59 58 57 57 56 55

2 ACSR (7/1) 45 45 44 44 43 42

1/0 ACSR (6/1) 37 37 36 36 35 35

123.3 AAAC (7) 36 36 35 35 35 34

2/0 ACSR (6/1) 37 36 36 35 35 34

3/0 ACSR (6/1) 29 29 28 28 27 27

4/0 ACSR (6/1) 29 28 28 27 27 27

246.9 AAAC (7) 28 28 27 27 26 26

336.4 ACSR (18/1) 28 27 27 26 26 25

336.4 ACSR (26/7) 19 19 19 18 18 18

HEAVY LOADING DISTRICT

4 ACSR (7/1) 60 60 60 60 60 60

2 ACSR (6/1) 57 56 55 54 53 52

2 ACSR (7/1) 44 43 42 42 41 40

1/0 ACSR (6/1) 36 36 35 34 33 33

123.3 AAAC (7) 36 35 34 34 33 32

2/0 ACSR (6/1) 36 35 34 34 33 32

3/0 ACSR (6/1) 29 28 27 27 26 26

4/0 ACSR (6/1) 28 28 27 26 26 25

246.9 AAAC (7) 27 27 26 26 25 24

336.4 ACSR (18/1) 27 26 26 25 24 24

336.4 ACSR (26/7) 19 18 18 17 17 17

MAXIMUM LINE ANGLES (Degrees) ON SPOOL INSULATOR ASSEMBLIES

NESC Grade C Construction (Re-calculate for NESC Grade B)

(ANSI Clss 53-4 Spool Insulator)

Note: Decrease line angle by 1 degree for poles adjacent to a crossing span.
Bulletin 1728F-804 

Exhibit 2 

Page 1 

LONGITUDINAL LOADING ON CROSSARM ASSEMBLIES 

Applied vertical loads need to be considered when determining the permitted longitudinal 

loading of crossarm deadend assemblies. The following mathematical relationship, which relate 

vertical and longitudinal loading, has to be satisfied to avoid overstressing the wood fibers of 

crossarms: 

1

( ) ( )

+ ≤

∑ ∑

Permitted Longitudinal Moment Capacity

Applied Longitudinal Moments

Permitted Vertical Moment Capacity

Applied Vertical Moments

 

The following applies to RUS standard distribution, deadend, crossarm assemblies: 

• Permitted Vertical Moment (Capacity) of Assembly = N x Mv x Fs 

• Permitted Longitudinal Moment (Capacity) of Assembly = N x Mh x Fs 

• Σ Applied Vertical Moments = 

 [( ) ( )] [( ) ( )] in out OLV in out W FOLV M LW D1 × S ×W1 + S ×W2 × F + D2 × S ×W3 + S × 4 × +

• Σ Applied Longitudinal Moments = 

 [ ( ) ( )] D1 × L1−in − L1−out + D2 × L2−in − L2−out × FOLL

The units of measure of the above four groups of terms are “ft-lbs.” Note that all of the 

calculations apply to one-half of the crossarm assembly (on either the right or left side of the 

pole looking parallel to the line). Each conductor attachment location, at a distance D1 or D2

from the center of the assembly, has either one conductor attached (“into” the assembly) or has 

two back-to-back conductors attached (one “into” and one “out from” the assembly). 

Following are the definitions and values of the variables in the above equations: 

Mv = 7,650 Vertical crossarm moment (capacity) (ft-lbs)

Mh = 5,060 Longitudinal crossarm moment (capacity) (ft-lbs) 

MLW = 1,000 Load moment attributed to weight of lineworker (ft-lbs) 

Fs = 0.85 Strength Factor (2002 NESC Table 261-1A) - Grade C 

= 0.65 " " " " " " - Grade B 

FOLV = 1.90 Overload factor - Vertical (2002 NESC Table 253-1) - Grade C 

= 1.50 " " " " " " " - Grade B 

FOLL = 1.30 Overload factor - Longitudinal (2002 NESC Table 253-1) - Grade C 

= 1.65 " " " " " " " - Grade B 

D1 = 1.75 Distance to nearest conductors on 10-foot crossarm assemblies (ft) 

D2 = 4.50 Distance to farthest conductors on 10-foot crossarm assemblies (ft) 

D1 = 3.50 Distance to conductor(s) on 8-foot crossarm assemblies (ft) 

Wi = Vertical unit weight of conductor plus NESC ice and wind loads (lbs/ft)

Sin = One-half of the total span length "into" the assembly (ft)
Bulletin 1728F-804 

Exhibit 2 

Page 2 

Sout = One-half of the total span length "out from" the assembly (ft)

N = Number of crossarms 

Lin = Tension of each conductor “into” the assembly (lbs) 

Lout = Tension of each conductor “out from” the assembly (lbs) 

For purposes of simplifying mechanical loading calculations, the following assumptions and 

approximations are made: 

• All of the conductor spans “into” a crossarm assembly have the same length; all of the 

conductor spans “out from” a crossarm assembly have the same length. The length “S,” 

where S = Sin + Sout, is called a “weight span.” 

• The tensions of all of the conductors into the crossarm assembly (Lin) are the same; the 

tensions of all of the conductors out from the crossarm assembly (Lout) are the same. “L” is 

the difference of the conductor tensions (L = Lin -Lout) at each (phase) conductor attachment 

location on the assembly. 

• All of the conductors attached to the crossarm assembly are the same type and size as the 

largest conductor. Thus in the above equation: W1 = W2 = W3 =W4 = W. 

• A load moment (MLW ) of 250 pounds (which might be attributed to a lineworker, materials 

or equipment) times 2 feet and times a constant overload factor of 2.0 (the product equals 

1,000 ft-lbs) is added to the applied vertical load moments to satisfy NESC Rule 261D4b 

requirements. (Note: Standard construction practices and RUS discourage lineworkers 

from standing on crossarms.) 

After applying the above assumptions and substitutions, the equation can be simplified and rewritten as: 

( ) ( ) ( )

1

,1 000 1 2 1 2

≤

× ×

+ × ×

+

× ×

+ × × × +

h s

OLL

v s

OLV

N M F

D D L F

N M F

D D W S F

 (ft-lbs) 

This equation can be solved for “L” as a function of all of the other variables in the equation. 

Tables A and B show the calculated permitted unbalanced conductor tensions (“L”) for several 

commonly used distribution conductors versus three different weight spans (“S”), for standard 

RUS crossarm deadend assemblies and NESC Grade C construction. 
Bulletin 1728F-804 

Exhibit 2 

Page 3 

Vertical

Loading WEIGHT SPANS** (feet) WEIGHT SPANS** (feet) 

CONDUCTOR SIZE (lbs/ft) 200 300 400 200 300 400

4 ACSR (7/1) 0.0670 1,730 1,720 1,710 2,670 2,670 2,660

2 ACSR (6/1) 0.0913 1,720 1,710 1,700 2,670 2,660 2,650

123.3 AAAC (7) 0.1157 1,720 1,710 1,700 2,660 2,650 2,640

1/0 ACSR (6/1) 0.1452 1,710 1,700 1,680 2,660 2,640 2,630

2/0 ACSR (6/1) 0.1831 1,700 1,690 1,670 2,650 2,630 2,610

3/0 ACSR (6/1) 0.2309 1,700 1,670 1,650 2,640 2,620 2,600

246.9 AAAC (7) 0.2318 1,700 1,670 1,650 2,640 2,620 2,600

4/0 ACSR (6/1) 0.2911 1,680 1,660 1,630 2,630 2,600 2,570

312.8 AAAC (19) 0.2936 1,680 1,650 1,630 2,630 2,600 2,570

336.4 ACSR (18/1) 0.3653 1,670 1,630 1,600 2,610 2,580 2,540

4 ACSR (7/1) 0.2247 1,700 1,670 1,650 2,640 2,620 2,600

2 ACSR (6/1) 0.2673 1,690 1,660 1,640 2,630 2,610 2,580

123.3 AAAC (7) 0.3172 1,680 1,650 1,620 2,620 2,590 2,560

1/0 ACSR (6/1) 0.3467 1,670 1,640 1,610 2,620 2,580 2,550

2/0 ACSR (6/1) 0.3998 1,660 1,620 1,590 2,610 2,570 2,530

3/0 ACSR (6/1) 0.4647 1,650 1,610 1,560 2,600 2,550 2,510

246.9 AAAC (7) 0.4846 1,650 1,600 1,550 2,590 2,540 2,500

4/0 ACSR (6/1) 0.5439 1,630 1,580 1,530 2,580 2,530 2,470

312.8 AAAC (19) 0.5709 1,630 1,570 1,520 2,570 2,520 2,460

336.4 ACSR (18/1) 0.6557 1,610 1,550 1,490 2,560 2,490 2,430

4 ACSR (7/1) 0.5379 1,640 1,580 1,530 2,580 2,530 2,480

2 ACSR (6/1) 0.5989 1,620 1,570 1,510 2,570 2,510 2,450

123.3 AAAC (7) 0.6741 1,610 1,540 1,480 2,550 2,490 2,420

1/0 ACSR (6/1) 0.7036 1,600 1,540 1,470 2,550 2,480 2,410

2/0 ACSR (6/1) 0.7719 1,590 1,520 1,440 2,540 2,460 2,390

3/0 ACSR (6/1) 0.8539 1,570 1,490 1,410 2,520 2,440 2,350

246.9 AAAC (7) 0.8927 1,570 1,480 1,390 2,510 2,430 2,340

4/0 ACSR (6/1) 0.9520 1,560 1,460 1,370 2,500 2,410 2,320

312.8 AAAC (19) 1.0037 1,550 1,450 1,350 2,490 2,390 2,300

336.4 ACSR (18/1) 1.1015 1,530 1,420 1,310 2,470 2,370 2,260

NOTES: Reduce tabulated tensions by 40% for NESC Grade B construction.

 *(Lbs/Phase) means tension difference at each point on crossarms where conductors are attached.

 **Weight span equals 1/2 span length into assembly plus 1/2 span length out from assembly.

 Weight Span for single deadend assembies only equals 1/2 span length into assembly.

 Last 3 notes at end of TABLE B also apply to TABLE A.

TABLE A

PERMITTED UNBALANCED CONDUCTOR TENSION ( Lbs / Phase )*

NESC LIGHT LOADING DISTRICT (0.00" Ice; 9 lb Wind)

NESC MEDIUM LOADING DISTRICT (0.25" Ice; 4 lb Wind)

NESC HEAVY LOADING DISTRICT (0.50" Ice; 4 lb Wind)

2 CROSSARMS 3 CROSSARMS

SINGLE and DOUBLE DEADEND ASSEMBLIES; 1 PHASE EACH SIDE OF POLE- NESC Grade C 
Bulletin 1728F-804 

Exhibit 2 

Page 4 

Vertical

Loading WEIGHT SPANS** (feet) WEIGHT SPANS** (feet) 

CONDUCTOR SIZE (lbs/ft) 200 300 400 200 300 400

4 ACSR (7/1) 0.0670 960 950 950 1,490 1,480 1,480

2 ACSR (6/1) 0.0913 950 950 940 1,480 1,480 1,470

123.3 AAAC (7) 0.1157 950 940 930 1,480 1,470 1,460

1/0 ACSR (6/1) 0.1452 940 930 920 1,470 1,460 1,450

2/0 ACSR (6/1) 0.1831 940 920 900 1,470 1,450 1,430

3/0 ACSR (6/1) 0.2309 930 910 880 1,460 1,440 1,410

246.9 AAAC (7) 0.2318 930 900 880 1,460 1,430 1,410

4/0 ACSR (6/1) 0.2911 920 890 860 1,450 1,420 1,390

312.8 AAAC (19) 0.2936 920 890 860 1,450 1,420 1,390

336.4 ACSR (18/1) 0.3653 900 870 830 1,430 1,400 1,360

4 ACSR (7/1) 0.2247 930 910 890 1,460 1,440 1,420

2 ACSR (6/1) 0.2673 920 890 870 1,450 1,420 1,400

123.3 AAAC (7) 0.3172 910 880 850 1,440 1,410 1,380

1/0 ACSR (6/1) 0.3467 900 870 840 1,430 1,400 1,370

2/0 ACSR (6/1) 0.3998 890 860 820 1,420 1,390 1,350

3/0 ACSR (6/1) 0.4647 880 840 790 1,410 1,370 1,320

246.9 AAAC (7) 0.4846 880 830 780 1,410 1,360 1,310

4/0 ACSR (6/1) 0.5439 870 810 760 1,400 1,340 1,290

312.8 AAAC (19) 0.5709 860 810 750 1,390 1,340 1,280

336.4 ACSR (18/1) 0.6557 850 780 720 1,380 1,310 1,250

4 ACSR (7/1) 0.5379 870 820 760 1,400 1,350 1,290

2 ACSR (6/1) 0.5989 860 800 740 1,390 1,330 1,270

123.3 AAAC (7) 0.6741 840 780 710 1,370 1,310 1,240

1/0 ACSR (6/1) 0.7036 840 770 700 1,370 1,300 1,230

2/0 ACSR (6/1) 0.7719 820 750 670 1,350 1,280 1,200

3/0 ACSR (6/1) 0.8539 810 720 640 1,340 1,250 1,170

246.9 AAAC (7) 0.8927 800 710 630 1,330 1,240 1,160

4/0 ACSR (6/1) 0.9520 790 700 600 1,320 1,230 1,130

312.8 AAAC (19) 1.0037 780 680 580 1,310 1,210 1,110

336.4 ACSR (18/1) 1.1015 760 650 550 1,290 1,180 1,080

NOTES: Reduce tabulated tensions by 40% for NESC Grade B construction.

 *(Lbs/Phase) means tension difference at each point on crossarms where conductors are attached.

 **Weight span equals 1/2 span length into assembly plus 1/2 span length out from assembly.

 Calculations assume all conductors same size and type as largest conductor and level spans.

 Assemblies have been multiplied by strength factor of 0.85 (2002 NESC Table 261-1A).

 Applied loads have been multiplied by overload factors (2002 NESC Table 253-1).

TABLE B

PERMITTED UNBALANCED CONDUCTOR TENSION ( Lbs / Phase )*

DOUBLE DEADEND ASSEMBLIES - 2 PHASES EACH SIDE OF POLE - NESC Grade C 

NESC LIGHT LOADING DISTRICT (0.00" Ice; 9 lb Wind)

NESC MEDIUM LOADING DISTRICT (0.25" Ice; 4 lb Wind)

NESC HEAVY LOADING DISTRICT (0.50" Ice; 4 lb Wind)

2 CROSSARMS 3 CROSSARMS
Bulletin 1728F-804 

Exhibit 3 

Page 1 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

A1 A1.1 No material changes 

A1A A1.2 No material changes 

A1-1 A2.1 No material changes 

A1-1A A2.2 No material changes 

A1P A1.1P No material changes 

A1AP A1.2P No material changes 

A1-1AP A2.2P No material changes 

A1-1P A2.1P No material changes 

A2 A2.3 No material changes 

A2P A2.3P No material changes 

A3 A3.1 Replace 2 washers abutting pole 

A4 A4.1 Replace 4 washers abutting pole 

A5 A5.1 Replace 2 washers abutting pole 

A5-1 Discontinued (Material same as A5.1; Replaced with A5.2G)

A5-2 A5.2 Replace 2 washers abutting pole 

A5-2A Discontinued (Same as A5.2 and note)

A5-3 Discontinued (Same as A5.1 and note)

A5-4 Discontinued (Combination of A5.1, A1.1 and A5.2G)

A6 A6.1 Replace 4 washers abutting pole 

A7 A5.21 No material changes 

A7-1 A5.31 No material changes 

A8 A6.21 No material changes 

A9 A2.21 Add 4 washers under crossarm pins 

A9P A2.21P Add 2 washers under crossarm pins 

A9-1 A1.11 Add 2 washers under crossarm pins 

A9-1P A1.11P Add 1 washer under crossarm pin 

A22 Discontinued (Combination of A1.11, A1.11 and A1.12G) 

A22P Discontinued (Combination of A1.11P, A1.1 and A1.12G)

B1 B1.11 Add 2 washers under crossarm pins 

B1A B1.12 Add 2 washers under crossarm pins 

B1P B1.11P No material changes 

B1AP B1.12P No material changes 

B1-1 B2.24 Add 4 washers under crossarm pins 

B1-1A B2.25 Add 4 washers under crossarm pins 

B1-1P B2.24P No material changes 

B1-1AP B2.25P No material changes 

B2 B2.21 Add 4 washers under crossarm pins 

B2P B2.21P No material changes 

B3 B3.1 Replace 2 washers abutting pole and slight material changes 
Bulletin 1728F-804 

Exhibit 3 

Page 2 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

B3A Discontinued (Similar to B3.1)

B4-1 Discontinued (Replaced with guide B4.1G)

B4-1A Discontinued (Replaced with guide B4.1G)

B5-1 B5.1 Replace 3 washers abutting pole and slight material changes 

B5-1A Discontinued (Similar to B5.1)

B7 B5.21 Neutral position and material slightly different 

B7-1 B5.31 Neutral position and material slightly different 

B8 B6.21 Neutral and material slightly different 

B9 B2.22 Add 6 washers under crossarm pins 

B9-1 B1.14 Add 3 washers under crossarm pins 

B9-2 Discontinued (Same as B2.22 except for 10-foot crossarms)

B9-3 Discontinued (Same as B1.14 except for 10-foot crossarms)

B9P B2.22P Add 2 washers under crossarm pins 

B9-1P B1.14P Add 1 washer under crossarm pin 

B9-2P Discontinued (Same as B2.22P except for 10-foot crossarms)

B9-3P Discontinued (Same as B1.14P except for 10 foot crossarms)

B22 Discontinued (Same as two B1.11s) 

B22P Discontinued (Same as two B1.11Ps) 

C1 C1.11 Add 2 washers under crossarm pins 

C1A C1.12 Add 2 washers under crossarm pins 

C1P C1.11P No material changes 

C1AP C1.12P No material changes 

C1PL Discontinued (Same as C1.11P except crossarm braces)

C1-1 C2.24 Add 4 washers under crossarm pins 

C1-1A C2.25 Add 4 washers under crossarm pins 

C1-1AP C2.24P No material changes 

C1-1P C2.25P No material changes 

C1-3P C2.21P No material changes 

C1-4PL Discontinued (Second center insulator not needed)

C1-2 C1.11L No material changes 

C1-3 C2.21L No material changes 

C1-4 C1.13L No material changes 

C2 C2.21 Add 4 washers under crossarm pins 

C2-1 C2.52 Add 6 washers under crossarm pins 

C2-2 C2.52L No material changes 

C2-2PL C2.52P 2 fewer double arming bolts – optional

C3 C3.1 Replace 4 washers abutting pole; add neutral eyebolt 

C3-1 C3.1L Replace 8 washers abutting pole 

C4-1 Discontinued (Replaced with guide C4.1G)
Bulletin 1728F-804 

Exhibit 3 

Page 3 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

C5-1 C5.2 Replace 4 washers abutting pole 

C7 C5.21 Replace 1 washer abutting pole 

C7-1 C5.31 Replace 1 washer abutting pole 

C7A C5.71L Replace 1 washer abutting pole 

C7-2 C5.22 Slight material changes 

C8 C6.21 Different neutral and crossarm brace materials 

C8-1 Discontinued (Replaced with C6.51)

C8-2 Discontinued (Similar to C5.21)

C8-3 C6.31L Different neutral position and materials 

C9 C2.51 Add 8 washers under crossarm pins and anti-split bolt 

C9-1 C1.41 Add 4 washers under crossarm pins 

C9-2 C2.51L Replace 2 crossarm pins with clamp-type 

C9-3 C1.41L Replace 1 crossarm pin with clamp-type 

C9-1P C1.41P Add 1 washer under crossarm pin 

C9-2PL C2.51P Add 2 washers under crossarm pins; 2 fewer double arming 

bolts – optional 

C9-3PL Discontinued (Nearly same as C9-1P)

C22 Discontinued (Combination of C1.11, A1.11 and C6.91G)

C24 Discontinued (Replaced with C6.91G)

DC-C1 D1.81 Add 6 washers under crossarm pins 

DC-C1A Discontinued 

DC-C1-1A Discontinued 

DC-C1PL Discontinued (Replaced with D1.81P)

DC-C1-3PL Discontinued (Replaced with D2.91P)

DC-C2 Discontinued (Wrong neutral for line angle)

DC-C2-1 D2.91 Add 12 washers under crossarm pins 

DC-C3 Discontinued (Replaced by two C3’s and D3.1G)

DC-C4-1 Discontinued (Replaced by four C3’s and D4.1G)

DC-C8 D6.91 Slightly different neutral and other material. 

DC-C25 Discontinued (Replace with guide drawing D5.91G)

E1-1 Discontinued (See E1.1)

E1-2 E1.1 Add Guy Marker 

E1-3 E1.1L Add Guy Marker 

E2-1 Discontinued 

E2-2 E1.4 Different guy strand wire (Different permitted loads)

E2-3 E1.4L Replace 5/8” thimble eye bolt and nut with 3/4” 

E3-2 Discontinued 

E3-3 E1.2 Add Guy Marker (Different permitted loads)

E3-10 Discontinued 
Bulletin 1728F-804 

Exhibit 3 

Page 4 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

E4-2 Discontinued (See note 3 on E1.4)

E4-3 Discontinued (See note 3 on E1.4)

E5-1 Discontinued 

E5-2 Discontinued 

E6-2 Discontinued (See E2.1G)

E6-3 Discontinued (See E2.1G)

E7-2 Discontinued (See E3.1LG)

E7-3 Discontinued (See E3.1LG)

E8-2 Discontinued (See E4.3LG)

E8-3 Discontinued (See E4.3LG)

E11 Discontinued (See E1.2)

E12 Discontinued (See E1.2)

F1-1 F1.6 No material changes 

F1-2 F1.8 No material changes 

F1-3 F1.10 No material changes 

F1-4 F1.12 No material changes 

F1-1C Discontinued (Not in List of Materials)

F1-2C Discontinued (Not in List of Materials)

F1-3C Discontinued (Not in List of Materials)

F1-1P F3.6 No material changes 

F1-2P F3.8 No material changes 

F1-3P F3.10 No material changes 

F1-4P F3.12 No material changes 

F1-1S F2.6 No material changes 

F1-2S F2.8 No material changes 

F1-3S F2.10 No material changes 

F1-4S F2.12 No material changes 

F2-1 Discontinued 

F2-2 Discontinued 

F2-3 Discontinued 

F2-4 Discontinued 

F4-1E F4.1 No material changes 

F4-1S F4.2 No material changes 

F5-1 F5.1 No material changes 

F5-2 F5.2 No material changes 

F5-3 F5.3 No material changes 

F6-1 F6.6 No material changes 

F6-2 F6.8 No material changes 

F6-3 F6.10 No material changes 
Bulletin 1728F-804 

Exhibit 3 

Page 5 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

G9- G1.7 No material changes 

G65- Discontinued 

G105- G1.2 No material changes 

G10- G1.8 No material changes 

G66- Discontinued 

G106- G1.3 No material changes 

G39- Discontinued - Same as G9- 

G67- Discontinued 

G136- Discontinued - Same as G105- 

G210- G2.1 No material changes (Drawing modified)

G310- G3.1 No material changes (Drawing modified)

G311- G3.2 No material changes (Drawing modified)

G312- G3.3 No material changes (Drawing modified)

J5 J1.2 No material changes 

J6 J3.1 No material changes 

J7 J2.2 No material changes 

J7C Discontinued - Same as J7 

J8 J1.1 No material changes 

J10 J2.1 No material changes 

J11 Discontinued - Same as J6 

J12 J4.1 No material changes 

K10 K2.1 No material changes 

K11 K1.4 No material changes 

K14 K1.3 No material changes 

K10C K2.2 No material changes 

(K10C) K2.3 No material changes 

K10L Discontinued - Same as K10 

K11L Discontinued - Same as K11 

K14L Discontinued - Same as K14 

K11C K1.2 No material changes 

K14C K1.1 No material changes 

K15C K1.5 No material changes 

K16C K3.2 No material changes 

K17 K3.1 No material changes 

K17L Discontinued - Same as K17 

M2-1 Discontinued 

M2-11 H1.1 No material changes 

M2-2 Discontinued 

M2-12 H5.1 No material changes 
Bulletin 1728F-804 

Exhibit 3 

Page 6 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

M2-2A Discontinued 

M2-12A H5.2 No material changes 

M2-2A2 Discontinued 

M2-12A2 Discontinued 

M2-3 Discontinued 

M2-13 H2.1 No material changes 

M2-7 Discontinued 

M2-17 Discontinued 

M2-9 Discontinued 

M2-15 H3.1 No material changes 

M2-15A H4.1 No material changes 

M3-1A Discontinued 

M3-4 S1.1 Replace lag screw with machine bolt and washer 

M3-2A S2.21 Slight material changes 

M3-3A S2.31 Slight material changes 

M3-3B S2.3 No material changes 

M3-10 R1.1 Slight material changes (Add bracket)

M3-41 S3.1 Slight material changes (Add bracket)

M3-11 Discontinued (See R3.1)

M3-12 Discontinued (Replaced with R3.1)

M3-11A R2.1 No material changes 

M3-12A R3.1 No material changes 

M3-15 S2.32 Slight material changes 

M3-23 Discontinued 

M3-24 Discontinued 

M3-25 Discontinued 

M3-23A R1.2 Slight material changes (Add bracket)

M3-24A R2.2 Slight material changes 

M3-25A R3.2 Slight material changes 

M3-30 R3.3 Slight material changes 

M5-1 Discontinued 

M5-2 A1.01 No material changes 

M5-5 A1.011 Add 1 washer under crossarm pin 

M5-6 P1.01 No material changes 

M5-7 A1.011P No material changes 

M5-8 A5.02 No material changes 

M5-9 S1.01 No material changes 

M5-10 S1.02 No material changes 

M5-11 Discontinued 
Bulletin 1728F-804 

Exhibit 3 

Page 7 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

M5-12 Discontinued 

M5-13 W3.2 No material changes 

M5-14 Discontinued 

M5-16 Discontinued 

M5-17 W3.1 No material changes 

M5-18 A1.01P No material changes 

M5-19 N1.2 No material changes 

M5-20 Discontinued (See A5.3)

M5-21 Discontinued 

M5-22 Discontinued 

M5-23 Discontinued 

M5-24 A5.01 No material changes 

M5-25 N5.1 Replace 1 washer abutting pole 

M5-26 N5.3 Replace 1 washer abutting pole 

M7-11 Y1.1 Minor material changes – replace crossarms with bracket

M7-13 Y1.3 Minor material changes 

M8 Q1.1 Minor material changes 

M8-6 Q3.1 No material changes 

M8-9 Q2.2G Modified guide drawing; no material 

M8-10 Q2.1G Modified guide drawing; no material 

M8-11 Q3.3 Minor material changes 

M8-12 Q3.2 Minor material changes 

M8-15 Q4.1 Minor material changes 

M9-11 Y3.1 No material changes 

M9-12 Y3.2 Minor material changes 

M9-13 Y3.3 Minor material changes 

M19 W2.1G Modified guide drawing; no material 

M20 W1.1G Modified guide drawing; no material 

M21 Discontinued (Guide drawing)

M22-1 Discontinued (Guide drawing)

M22-2 Discontinued (Guide drawing)

M24 K4.1G Modified guide drawing; no material 

M24-1 Discontinued (Guide drawing)

M24-10 K4.2G Modified guide drawing; no material 

M26-5 Discontinued (Guide drawing)

M27 Discontinued (Guide drawing)

M27-1 Discontinued (Guide drawing)

M27-1A G1.1G Modified guide drawing; no material 

M27-2 Discontinued (Guide drawing)
Bulletin 1728F-804 

Exhibit 3 

Page 8 

Disposition of Assemblies in Bulletin 50-3 (D 804) 

Old 

Assembly 

Number 

(Bulletin 50-3)

New 

Assembly 

Number 

(1728F-804) 

Material Changes 

and 

Comments 

M28 Discontinued (See G1.1G)

M29-1 Discontinued (See guide drawings in Sections A and C)

M29-2 Discontinued (See guide drawings in Sections A and C)

M30-1 Discontinued (Guide drawing)

M30-2 Discontinued (Guide drawing)

M40-11 Discontinued (Guide drawing)

M41-1 Discontinued (Replaced assemblies L1.1 and L3.1)

M41-10 Discontinued (Replaced assemblies L1.2 and L3.2)

M42-3 Discontinued (Replaced assemblies L1.3 and L3.4)

M42-11 Discontinued (Replaced assemblies L1.5 and L3.5)

M42-13 Discontinued (Replaced assembly L2.5)

M42-21 Discontinued (Replaced assemblies L1.4 and L3.3)

M43-4 Discontinued (Guide drawing)

M43-10 Discontinued (Guide drawing)

M52-3 Discontinued (Guide drawing)

M52-4 Discontinued (Guide drawing)

R1 M1.30G Modified guide drawing; no material 

 249 Total Assemblies (257 – 8 discontinued duplicates)

 82 Discontinued

 94 Re-used: No material changes 

 37 Re-used: Washer changes only 

 36 Re-used: Other slight material changes

 167 Total assemblies re-used

 32 Total Guide Drawings 

 24 Discontinued 

 8 Re-used

 180 Total pages 
Bulletin 1728F-804 

Exhibit 4 

Page 1 

Bulletin 1728F-804: New Assemblies and Guide Drawings 

NUMBER ASSEMBLY / GUIDE DRAWING DESCRIPTION 

NEW SINGLE-PHASE PRIMARY POLE TOP ASSEMBLIES 

A1.011L SINGLE SUPPORT - PRIMARY 

A1.04N 

A1.04NP 

SINGLE SUPPORT – NARROW PROFILE 

A1.3 SINGLE SUPPORT 

A1.3P SINGLE SUPPORT (POST INSULATORS) 

A1.4N 

A1.5N 

SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

A1.4NP 

A1.5NP 

SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

 (POST INSULATORS) 

A1.6N SINGLE SUPPORT - NARROW PROFILE 

A1.6NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

A1.12G SINGLE PHASE JUNCTION GUIDE 

A2.01 

A2.01P 

A2.021 

A2.021P 

DOUBLE SUPPORT - PRIMARY 

A2.04N 

A2.04NP 

DOUBLE SUPPORT – NARROW PROFILE 

A2.4N 

A2.5N 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

A2.4NP 

A2.5NP 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

 (POST INSULATORS) 

A2.6N DOUBLE SUPPORT - NARROW PROFILE 

A2.6NP DOUBLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

A3.2 

A3.3 

SUSPENSION ANGLE 

A3.4 

A3.5 

A3.6 

A3.7 

A3.8 

A3.9 

SUSPENSION ANGLE 

A4.2 DEADEND ANGLE (15° - 90°) 

A5.03 SINGLE DEADENDS 

A5.3 SINGLE DEADENDS 
Bulletin 1728F-804 

Exhibit 4 

Page 2 

A5.4 

A5.5 

A5.6 

A5.7 

A5.8 

A5.9 

SINGLE DEADENDS 

A5.2G SINGLE PHASE TAP GUIDE 

A5.3NG SINGLE PHASE TAP GUIDE - NARROW PROFILE 

A5.4NG SINGLE PHASE TAP GUIDE - NARROW PROFILE 

 (WITH CUTOUT AND ARRESTER) 

A6.2 DOUBLE DEADEND (FEED THROUGH) 

A6.22G DOUBLE DEADEND GUIDE (FEED THROUGH ON CROSSARMS) 

NEW TWO-PHASE PRIMARY POLE TOP ASSEMBLIES 

B1.1N 

B1.2N 

SINGLE SUPPORT - NARROW PROFILE (TANGENT)

B1.1NP 

B1.2NP 

SINGLE SUPPORT - NARROW PROFILE (TANGENT) 

 (POST INSULATORS)

B1.3N SINGLE SUPPORT - NARROW PROFILE

B1.3NP SINGLE SUPPORT – NARROW PROFILE (POST INSULATORS) 

B1.4N 

B1.5N 

SINGLE SUPPORT - NARROW PROFILE (TANGENT)

B1.4NP 

B1.5NP 

SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

 (POST INSULATORS)

B1.6N SINGLE SUPPORT - NARROW PROFILE

B1.6NP SINGLE SUPPORT - NARROW PROFILE (POST INSULATORS) 

B1.7N 

B1.8N 

SINGLE SUPPORT - NARROW PROFILE (TANGENT)

B1.7NP 

B1.8NP 

SINGLE SUPPORT - NARROW PROFILE (TANGENT) 

 (POST INSULATORS)

B1.9N SINGLE SUPPORT - NARROW PROFILE

B1.9NP SINGLE SUPPORT - NARROW PROFILE (POST INSULATORS)

B1.13 SINGLE SUPPORT ON CROSSARM 

B1.13P SINGLE SUPPORT ON CROSSARM (POST INSULATORS) 

B2.1N 

B2.2N 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

B2.1NP 

B2.2NP 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

 (POST INSULATORS) 

B2.3N DOUBLE SUPPORT - NARROW PROFILE 

B2.3NP DOUBLE SUPPORT - NARROW PROFILE (POST INSULATORS) 

B2.4N 

B2.5N 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT)

B2.4NP DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 
Bulletin 1728F-804 

Exhibit 4 

Page 3 

B2.5NP (POST INSULATORS) 

B2.6N DOUBLE SUPPORT - NARROW PROFILE

B2.6NP DOUBLE SUPPORT - NARROW PROFILE (POST INSULATORS)

B2.7N 

B2.8N 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT)

B2.7NP 

B2.8NP 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

 (POST INSULATORS) 

B2.9N DOUBLE SUPPORT - NARROW PROFILE

B2.9NP DOUBLE SUPPORT - NARROW PROFILE (POST INSULATORS)

B3.2 

B3.3 

SUSPENSION ANGLE 

B3.4 

B3.5 

B3.6 

B3.7 

B3.8 

B3.9 

SUSPENSION ANGLE 

B4.1G DEADEND ANGLE GUIDE (900

 – 1500) 

B4.2G DEADEND ANGLE GUIDE (150

 – 900) 

B5.2 

B5.3 

SINGLE DEADENDS 

B5.4 

B5.5 

B5.6 

B5.7 

B5.8 

B5.9 

SINGLE DEADENDS 

NEW THREE-PHASE PRIMARY POLE TOP ASSEMBLIES 

C1.1N 

C1.2N 

SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

C1.1NP 

C1.2NP 

SINGLE SUPPORT – NARROW PROFILE (TANGENT) 

 (POST INSULATORS)

C1.3N SINGLE SUPPORT - NARROW PROFILE

C1.3NP SINGLE SUPPORT - NARROW PROFILE (POST INSULATORS)

C1.4N 

C1.5N 

SINGLE SUPPORT - NARROW PROFILE (TANGENT

C1.4NP 

C1.5NP 

SINGLE SUPPORT - NARROW PROFILE (TANGENT) 

 (POST INSULATORS)

C1.6N SINGLE SUPPORT - NARROW PROFILE

C1.6NP SINGLE SUPPORT - NARROW PROFILE (POST INSULATORS)

C1.7N 

C1.8N 

SINGLE SUPPORT - NARROW PROFILE (TANGENT)

C1.7NP 

C1.8NP 

SINGLE SUPPORT - NARROW PROFILE) (TANGENT) 

 (POST INSULATORS)
Bulletin 1728F-804 

Exhibit 4 

Page 4 

C1.9N SINGLE SUPPORT - NARROW PROFILE 

C1.9NP SINGLE SUPPORT - NARROW PROFILE (POST INSULATORS) 

C1.12L SINGLE SUPPORT ON CROSSARM – (TANGENT) 

 (LARGE CONDUCTORS) 

C1.13 SINGLE SUPPORT ON CROSSARM 

C1.13P SINGLE SUPPORT ON CROSSARM (POST INSULATORS) 

C1.81G THREE-PHASE JUNCTION GUIDE 

C2.1N 

C2.2N 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT)

C2.1NP 

C2.2NP 

DOUBLE SUPPORT – TANGENT (POST INSULATORS) 

 (NARROW PROFILE)

C2.3N DOUBLE SUPPORT - NARROW PROFILE

C2.3NG DOUBLE SUPPORT – NARROW PROFILE (ALTERNATIVE GUYING 

GUIDE 

C2.3NP DOUBLE SUPPORT - NARROW PROFILE (POST INSULATORS)

C2.4N 

C2.5N 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT)

C2.4NP 

C2.5NP 

DOUBLE SUPPORT – NARROW PROFILE TANGENT 

 (POST INSULATORS)

C2.6N DOUBLE SUPPORT - NARROW PROFILE

C2.6NP DOUBLE SUPPORT - NARROW PROFILE (POST INSULATORS)

C2.7N 

C2.8N 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT)

C2.7NP 

C2.8NP 

DOUBLE SUPPORT – NARROW PROFILE (TANGENT) 

 (POST INSULATORS)

C2.9N DOUBLE SUPPORT - NARROW PROFILE

C2.9NP DOUBLE SUPPORT - NARROW PROFILE (POST INSULATORS)

C3.2 

C3.3 

SUSPENSION ANGLE 

C3.4 

C3.5 

C3.6 

C3.7 

C3.8 

C3.9 

SUSPENSION ANGLE 

C4.1G DEADEND GUIDE (90O – 150O) 

C4.2G DEADEND GUIDE (15O – 90O) 

C5.1 

C5.3 

SINGLE DEADENDS - VERTICAL 

C5.4 

C5.5 

C5.6 

C5.7 

C5.8 

SINGLE DEADENDS - VERTICAL 
Bulletin 1728F-804 

Exhibit 4 

Page 5 

C5.9 

C5.11G SINGLE PHASE TAP GUIDE 

C5.21L 

C5.31L 

SINGLE DEADEND ON CROSSARMS (LARGE CONDUCTORS) 

C5.32 SINGLE DEADEND ON CROSSARMS - ALTERNATIVE 

C5.82G THREE PHASE HORIZONTAL TAP GUIDE 

C6.31 DOUBLE DEADEND ON CROSSARMS 

C6.21L DOUBLE DEADEND ON CROSSARMS (LARGE CONDUCTORS) 

C6.52 

C6.53 

DOUBLE DEADEND ON 10-FOOT CROSSARMS 

C6.52G DOUBLE DEADEND ON 10-FOOT CROSSARMS 

(FEEDTHROUGH GUIDE) 

C6.91G DOUBLE DEADENDS (BUCKARMS) GUIDE 

NEW DOUBLE CIRCUIT PRIMARY POLE TOP ASSEMBLIES 

D1.4N 

D1.4NP 

D1.5N 

D1.5NP 

SINGLE SUPPORT - NARROW PROFILE – (TANGENT) 

 (and POST INSULATORS 

D1.82 SINGLE SUPPORT ON CROSSARMS – (TANGENT) 

D1.81L 

D1.82L 

SINGLE SUPPORT ON CROSSARMS – (TANGENT) 

 (LARGE CONDUCTORS) 

D1.81P 

D1.82P 

SINGLE SUPPORT ON CROSSARMS - (TANGENT) 

 (POST INSULATORS) 

D1.83 SINGLE SUPPORT ON CROSSARMS 

D1.83L SINGLE SUPPORT ON CROSSARMS (LARGE CONDUCTORS) 

D1.83P SINGLE SUPPORT ON CROSSARMS (POST INSULATORS) 

D2.9N 

D2.9NP 

DOUBLE SUPPORT - NARROW PROFILE 

 (and POST INSULATORS 

D2.91L DOUBLE SUPPORT ON CROSSARMS (LARGE CONDUCTORS) 

D2.91P DOUBLE SUPPORT ON CROSSARMS (POST INSULATORS) 

D3.1G SUSPENSION ANGLE GUIDE 

D4.1G DEADEND ANGLE GUIDE 

D5.91G THREE PHASE TAP GUIDE 

NEW GUYING ASSEMBLIES 

E1.3L SINGLE DOWN GUY - LARGE CONDUCTORS 

 (POLE BAND TYPE) 

E1.5 GUY STRAIN INSULATOR 

E2.1G DOUBLE DOWN GUY GUIDE - (THROUGH BOLT TYPE) 

E3.1LG THREE DOWN GUY GUIDE - HEAVY DUTY 

 (THROUGH BOLT TYPE) 

E4.3LG FOUR DOWN GUY GUIDE - LARGE CONDUCTORS 

 (POLE BAND TYPES) 
Bulletin 1728F-804 

Exhibit 4 

Page 6 

NEW TRANSFORMER ASSEMBLIES 

G1.2G POLE TYPE TRANSFORMER LOCATION GUIDE 

G1.4 

G1.5 

SINGLE-PHASE, CONVENTIONAL TRANSFORMER 

 (TANGENT POLE) 

G1.6 SINGLE-PHASE, CONVENTIONAL TRANSFORMER 

 (DEADEND POLE) 

G2.1G TRANSFORMER / METER CONNECTION GUIDE 

THREE-PHASE, OPEN-WYE - OPEN DELTA 

FOR 120/240 VOLT POWER LOADS 

G3.1G TRANSFORMER / METER CONNECTION GUIDE 

UNGROUNDED WYE - CENTER TAP GROUNDED DELTA 

FOR 120/240 VOLT POWER LOADS 

G3.2G TRANSFORMER / METER CONNECTION GUIDE 

UNGROUNDED WYE - CORNER GROUNDED DELTA 

FOR 240 OR 480 VOLT POWER LOADS 

G3.3G TRANSFORMER / METER CONNECTION GUIDE 

GROUNDED WYE - GROUNDED WYE 

FOR 120/208 VOLT POWER LOADS 

NEW GROUNDING ASSEMBLIES 

H5.3 GROUNDING IMPROVEMENT ASSEMBLIES - 

 WRAP-AROUND TYPE 

NEW TYING ASSEMBLIES 

L1.1 

L1.2 

PRIMARY ANGLE TYING ASSEMBLIES 

L1.3 

L1.4 

L1.5 

PRIMARY DEADEND TYING ASSEMBLIES 

L2.1 

L2.2 

NEUTRAL ANGLE TYING ASSEMBLIES 

L2.3 

L2.4 

L2.5 

NEUTRAL DEADEND TYING ASSEMBLIES 

L3.1 

L3.2 

NEUTRAL & SECONDARY ANGLE TYING ASSEMBLIES 

L3.3 

L3.4 

NEUTRAL & SECONDARY DEADEND TYING ASSEMBLIES - 

(COPPER) 

L3.5 

L3.6 

NEUTRAL & SECONDARY DEADEND TYING ASSEMBLIES - (ACSR) 

L4.1 TYING ASSEMBLIES, SERVICES 

L4.2 

L4.3 

L4.4 

TYING ASSEMBLIES, SERVICES 
Bulletin 1728F-804 

Exhibit 4 

Page 7 

NEW NEUTRAL ASSEMBLIES 

N1.1 NEUTRAL ASSEMBLIES - TANGENT 

N1.11 

N2.21 

NEUTRAL SUPPORTS ON CROSSARMS 

N2.1 

N2.1L 

NEUTRAL ASSEMBLIES - LARGE ANGLE 

N5.2 NEUTRAL ASSEMBLIES - (SINGLE DEADENDS) 

N6.1 NEUTRAL ASSEMBLY - DOUBLE DEADEND 

N6.21 NEUTRAL ASSEMBLY - DOUBLE DEADEND ON CROSSARMS 

NEW PROTECTION ASSEMBLIES 

P1.1 SURGE ARRESTERS - SINGLE PHASE 

P1.1NG SURGE ARRESTER GUIDE - NARROW PROFILE 

P1.3 SURGE ARRESTERS - 3 SINGLE PHASE 

P3.1G RAPTOR PROTECTION ASSEMBLY GUIDE 

SUPPORT ON 8-FOOT CROSSARMS (TANGENT) 

P3.2G RAPTOR PROTECTION ASSEMBLY GUIDE 

SUPPORT ON 10-FOOT CROSSARMS (TANGENT) 

P3.3G RAPTOR PROTECTION, PERCH GUARDS - GUIDE 

P3.4G RAPTOR PROTECTION, SINGLE-PHASE, CSP TRANSFORMER 

(TANGENT POLE) 

P3.5G RAPTOR PROTECTION ASSEMBLY GUIDE 

THREE-PHASE TRANSFORMER BANK 

NEW SECTIONALIZING ASSEMBLIES 

S2.01 MISCELLANEOUS CUTOUTS AND DISCONNECT SWITCH 

S1.1N CUTOUT GUIDE - NARROW PROFILE 

S1.3 COUTOUTS - (THREE SINGLE-PHASE) 

S3.2 SECTIONALIZER (WITH BYPASS CUTOUT) 

NEW VOLTAGE ALTERATION EQUIPMENT ASSEMBLIES 

Y2.1 

Y2.2 

AUTOTRANSFORMER, POLE MOUNTED 

(ONE SINGLE-PHASE, STEP-DOWN) 

Y3.4 SWITCHED CAPACITOR BANK - THREE PHASE 

 215 Total new assemblies (95 narrow profile)

 32 Total new guide drawings (4 narrow profile)
Bulletin 1728F-804 

Exhibit 5 

Page 1 

RUS Standard Format and Meaning of Overhead Distribution Assembly Numbers

The RUS standard numbering format for overhead distribution assemblies is: L1N1.N2

L1 is an alphabetic character that represents the category or group of similar assemblies 

that fulfill a similar and specific function in the construction or operation of an overhead 

distribution line. For example, the assemblies in category “C” are pole top assemblies 

that support three primary conductors (3-phase) and a neutral conductor. 

The following table shows the 19 distribution assembly categories and the letter (L1) 

RUS has assigned to represent them. 

DESIGNATED MEANINGS of ASSEMBLY CATEGORY NUMBERS (L1) 

A 1-Phase, pole-top H Grounds Q Metering 

B 2-Phase, pole-top J Secondaries R Reclosers 

C 3-Phase, pole-top K Services S Sectionalizing 

D Double Circuit, pole-top L Conductor Tying W Poles, Crossarms 

E Guys M Miscellaneous Y Volt. Alteration Equip. 

F Anchors N Neutrals 

G Transformers P Protection 

N1 is a numeric character that represents a subcategory or group of similar assemblies 

within a category. The different assemblies in a subcategory all fulfill the same specific 

functional purpose, but their function is somewhat different than the other assemblies 

within their associated assembly category (L1). For example, within categories “A” 

through “D” the subcategory “1” assemblies are all tangent or small angle pole top 

assemblies that (only) support the primary and neutral conductors. 

The following table shows the RUS designated meaning of the numbers (N1) that 

represent the 6 subcategories within pole-top assembly categories “A” through “D”. 

DESIGNATED MEANINGS of SUBCATEGORY 

NUMBERS (N1) for POLE TOP ASSEMBLIES 

1 Tangent or Small Angles (single pin or post type insulators) 

2 Small Angles (double pin or post type insulators) 

3 Large Angles (suspension type insulators) 

4 Large Angles (double deadends) 

5 Single Deadends or Taps 

6 Double Deadends 

RUS has assigned meanings to the subcategory numbers (N1) for the remaining 15 (L1) 

categories of overhead distribution assemblies, however, the list and meanings of these 

numbers is long and varied and beyond the scope of this summary exhibit. The 

remaining subcategory numbers and their assigned meanings are tabulated in RUS 
Bulletin 1728F-804 

Exhibit 5 

Page 2 

Bulletin 1728F-800, “Construction Assembly Unit Numbers and Format.” This bulletin 

is posted on the RUS website at: http://www.usda.gov/rus/electric/bulletins.htm. 

N2, which is always either a one or two digit number, is defined as the assembly

identification number. This number is used to differentiate the similar assemblies in a 

subcategory (N1) of assemblies 

RUS has assigned assembly identifications numbers from 11 through 99 to pole top 

assemblies that are constructed with crossarms. Furthermore, the two-digit crossarm 

assembly identification numbers have been assigned the designated meaning shown in 

the following table. 

DESIGNATED MEANINGS of ASSEMBLY IDENTIFICATION 

NUMBERS (N2) for CROSSARM ASSEMBLIES

11-19 Single 8-foot crossarms 

21-29 (1 set of) Double 8-foot crossarms 

31-39 (1 set of) Triple 8-foot crossarms 

41-49 Single 10-foot crossarms 

51-59 (1 set of) Double 10-foot crossarms 

61-69 Not used – Reserved for future

71-79 (1) Pre-assembled (manufactured) single crossarm assembly (item “gj”) 

81-89 Multiple crossarm assemblies 

91-99 Multiple crossarm assemblies 

The prefix “V” in front of a standard assembly number indicates that the assembly is used 

for 24.9/14.4 kV line construction. A standard assembly number with no prefix indicates 

that the assembly is used for 12.47/7.2 kV line construction. 

A suffix is an alphabetic character placed at the end of a standard assembly number. A 

suffix describes the type of the assembly. Presently, RUS only uses the following 4 

suffixes whose designated meanings are shown in parentheses: 

G (Guide drawing, not an assembly) N (Narrow profile construction assembly) 

L (Large conductor construction) P (Assembly with post type insulators) 

Not all assembly numbers have suffixes and some may have more than one suffix letter. 
Bulletin 1728F-804 

Exhibit 6 

TABLE OF SELECTED SI TO METRIC CONVERSIONS

LENGTH

To Convert From To Multiply By 

foot (ft.) meter (m) 3.048 E-01 

inch (in.) meter (m) 2.540 E-02 

kilometer (km) meter (m) 1.000 E+03 

mile (mi.) meter (m) 1.609344 E+03 

AREA

To Convert From To Multiply By 

circular mil (cmil) square meter 5.067075 E-10 

square centimeter square meter 1.000 E-04 

square foot square meter 9.290304 E-02 

square kilometer square meter 1.000 E+06 

square mile square meter 2.589988 E+06 

FORCE

To Convert From To Multiply By 

kilogram force (kgf) newton (N) 9.806650 

kip newton (N) 4.448222 E+03 

pound force (lbf) newton (N) 4.448222 

MASS

To Convert From To Multiply By 

pound (avoirdupois) (lb) kilogram (kg) 4.535924 E-01