UNITED STATES DEPARTMENT OF AGRICULTURE

Rural Utilities Service 

BULLETIN 1724E-150

RD-GD-2014-77

SUBJECT: Unguyed Distribution Poles—Strength Requirements

TO: RUS Electric Borrowers and RUS Electric Staff 

EFFECTIVE DATE: Date of Approval 

OFFICE OF PRIMARY INTEREST: Distribution Branch, Electric Staff Division

FILING INSTRUCTIONS: This bulletin replaces RUS Bulletin 1724E-150, “Unguyed 

Distribution Poles – Strength Requirements,” issued July 30, 2003. 

AVAILABILITY: This bulletin is available on the Rural Utilities Service website at 

http://www.rurdev.usda.gov/RDU_Bulletins_Electric.html. 

PURPOSE: This guide bulletin presents equations, data, and other information needed to 

determine: (1) the loads applied to unguyed wood distribution poles; (2) a pole’s strength 

requirements to sustain applied loads; and (3) maximum horizontal spans based on pole 

strengths. Sample solved problems are included in this bulletin to help the reader understand 

and apply the presented equations. At the end of this bulletin are tables of calculated ground line 

moments caused by wind on various species of wood poles and tables of permitted moments at 

the ground line of various species of wood poles commonly used for distribution construction. 

Disclaimer: The contents of this guidance document does not have the force and effect of law and is not meant 

to bind the public in any way. This document is intended only to provide clarity to the public regarding existing 

requirements under the law or agency policies.
RUS Bulletin 1724E–150

Page 2

TABLE OF CONTENTS

1 INTRODUCTION................................................................................................................... 4

2 CLASSIFICATION AND STRENGTH OF WOOD POLES ................................................ 5

3 EXPLANATION OF APPLIED LOADS AND MOMENTS ................................................ 5

4 HORIZONTAL MOMENTS ON A POLE............................................................................. 6

5 POLE STRENGTH AND REQUIREMENTS...................................................................... 10

6 DETERMINATION OF MAXIMUM HORIZONTAL SPANS.......................................... 12

7 CONTRIBUTORS ................................................................................................................ 13

EXHIBIT A: Ground Line Moments Caused by Wind on Wood Poles

Table 1: NESC Heavy Loading District/Grade C Construction

Table 2: NESC Heavy Loading District/Grade C Construction—Crossing Spans

Table 3: NESC Heavy Loading District/Grade B Construction 

Table 4: NESC Medium Loading District/Grade C Construction

Table 5: NESC Medium Loading District/Grade C Construction—Crossing Spans

Table 6: NESC Medium Loading District/Grade B Construction 

Table 7: NESC Light Loading District/Grade C Construction

Table 8: NESC Light Loading District/Grade C Construction—Crossing Spans

Table 9: NESC Light Loading District/Grade B Construction

EXHIBIT B: Permitted Moments at Ground Line of Wood Poles

Table 10: NESC Grade C Construction

Table 11: NESC Grade C Construction—Crossing Spans

Table 12: NESC Grade B Construction

INDEX:

POLES, DISTRIBUTION: Strength Requirements, Maximum Spans

ABBREVIATIONS

ACSR Aluminum Conductor, Steel Reinforced

ANSI American National Standards Institute

CFR Code of Federal Regulations

DTHL Design Tension Heavy Loading

EQ Equation

IEEE Institute of Electrical and Electronics Engineers

MOR Modulus of Rupture

NESC National Electrical Safety Code

RUS Rural Utilities Service

SYP Southern Yellow Pine (a type of wood pole)
RUS Bulletin 1724E–150

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UNITS OF MEASURE

in inch or inches (1 inch = 2.54 centimeters = 0.0254 meters)

in-lb inch-pounds (inch × pounds) (1 inch-pound = 0.370685 newtons)

ft foot or feet (1 foot = 0.3048 meters)

ft-lb foot-pounds (feet × pounds) (1 foot-pound = 4.448222 newtons)

kcmil 1,000 circular mils (1 kcmil= 5.067075 × 10-6 square meters)

kV kilovolts (1 kilovolt = 1,000 volts)
RUS Bulletin 1724E–150

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1 INTRODUCTION

a Purpose of Bulletin. This guide bulletin presents equations, data, and other

information needed to determine:

• The loads applied to unguyed wood distribution poles 55 ft or less in total 

length,

• A pole’s strength requirements to sustain applied loads, and

• Maximum horizontal spans based on pole strengths.

Sample solved problems are included in this bulletin to help the reader understand 

and apply the presented equations. Tables of calculated ground line moments 

caused by wind on wood poles are included in Exhibit A at the end of this 

bulletin. Tables of calculated permitted moments at the ground line of commonly

used wood poles are included in Exhibit B at the end of this bulletin.

b Scope of Bulletin. The presentation in this bulletin is limited to the horizontal

loading of unguyed wood distribution poles, 55 ft or less in total length, acting as 

simple cantilever beams or slender columns. Unguyed poles, according to RUS 

distribution construction standards, have a maximum line angle of 5 degrees. 

(The determination of the strength requirements of guyed poles is presented in 

Section 15 of RUS Bulletin 1724E-153, “Electric Distribution Line Guys and 

Anchors.”)0F

1 The loading effect of transformers and other heavy equipment on 

poles is not included in this bulletin.

c National Electrical Safety Code (NESC). Throughout this bulletin are

references to rules and selected data contained specifically in the 2012 edition of 

the NESC. At the time this bulletin was written, the 2012 edition was the latest 

edition of the NESC. Users of this bulletin should use the rules and data—as 

may be periodically updated, revised, and renumbered—from the most recent 

edition of the NESC. The NESC is published by the Institute of Electrical and 

Electronics Engineers, Inc. (IEEE).1F

2

d American National Standards Institute (ANSI). This bulletin also references

ANSI 05.1-2008, “Specifications and Dimensions for Wood Poles.”2F

3 This 

standard provides specifications for quality and dimensions of wood poles that are 

to be used in single-pole utility structures.

1 Copies available from: RUS-USDA, Publications Office, PDRA STOP 1522, Washington, DC 20250-1522; 

Telephone 202-720-8674. 2 Copies may be purchased from: IEEE Customer Service, 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08855-

1331; Telephone 1-800-678-4333. 3 Copies may be purchased from: American National Standards Institute, Inc., 1430 Broadway, New York, New 

York 10018; Telephone 212-354-3300.

 
RUS Bulletin 1724E–150

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2 CLASSIFICATION AND STRENGTH OF WOOD POLES

a Classification of Wood Poles. ANSI 05.1-2008 designates the fiber stress and

dimensions of natural wood poles and also classifies poles by wood species, 

length, and class. Usually a pole’s height and classification are abbreviated. For 

example, a pole identified as “35-6” indicates a 35-foot, (ANSI) Class 6 pole.

b Strength of Wood Poles by Class. Annex B of ANSI 05.1-2008 defines pole

classes so that poles of various species and lengths will have approximately equal 

load-carrying capability. The minimum circumferences specified at 6 feet from 

the butt, (shown in Tables 3 through 10) have been calculated such that each 

species in a given class will not exceed the ground line stresses tabulated in 

Annex B, when a given horizontal load is applied 2 feet from the top of the pole. 

For example, all Class 6 poles are capable of holding a 1,500 pound load applied 

transversely 2 feet from the top of the pole. The ground line circumferences of 

different species of poles in the same class will deviate because of the differences 

in allowable fiber stress.

3 EXPLANATION OF APPLIED LOADS AND MOMENTS

a NESC Loading Requirements. Section 25 of the NESC requires that wind and

ice loads on conductors and poles be determined according to the location 

(Heavy, Medium, or Light loading district) of construction. Assumed ice and 

wind loads have to be increased if they are expected to be greater than the 

minimum requirements of the NESC. If any part of a pole or the conductors 

attached to it is 60 feet or more above the ground, then extreme wind loading or 

extreme ice with concurrent wind loading has to be considered. Extreme wind 

loading (Rule 250C) or extreme ice with concurrent wind (Rule 250D) has to be 

applied, using the formulas and data of the NESC, if it is greater than the 

otherwise calculated wind and ice loading based on loading districts. Loads 

applied to wood poles have to be multiplied by the appropriate load factors of 

NESC Table 253-1. Conductor tension data for the appropriate loading case can 

then be determined as outlined in RUS Bulletin 1724E-152, “The Mechanics of 

Overhead Distribution Line Conductors.”

b Combined Loading Equation. All of the loads that can be expected to be applied

to a pole have to be considered in order to determine the pole’s strength 

requirements to sustain the loads. Loads are simultaneously applied to poles in 

both the horizontal and vertical directions. Poles need to have sufficient strength 

such that the following relationship is satisfied:

Mapplied

S +

Papplied

A ≤ MOR EQ 3.1

Where,

Mapplied = Moments induced in the pole (in-lb)
RUS Bulletin 1724E–150

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Papplied = Vertical loads on the pole (lb)

S = Section of modulus (in3)

A = Cross section area of pole (in2)

MOR = Modulus of rupture (1b/in2)

Usually the P/A portion of Equation 3.1 is negligible in comparison with the 

M/S portion of the equation and, thus, is ignored in the distribution pole strength 

calculations of this bulletin.

c Direction of Critical Loading. By using vector algebra, all horizontal loads

applied to a pole can be calculated in 2 component directions: longitudinal 

(parallel to the direction of the line) and transverse (perpendicular to the line). 

Usually there is only one direction of loading that dictates the minimum class of 

pole required to sustain all of the loads expected to be applied. This direction is 

called the direction of critical loading. Computations for pole strength 

requirements only need be made for the direction of critical loading when that 

direction is known. The direction of critical loading for unguyed poles is in the 

transverse direction.

4 HORIZONTAL MOMENTS ON A POLE

a Equations for Applied Moments. In this bulletin, an applied moment is the

multiplication product of an applied load or force times the distance from its 

centroid to the ground line of the pole. The unit of measure used in this bulletin 

for moments is foot-pounds (ft-lb). The sum of all of the applied moments,

multiplied by the appropriate NESC load factors, has to be determined before a 

pole of sufficient strength (i.e., class) can be selected. The total of all the ground 

line moments induced in a pole (Mg) is expressed as follows:

Mg = Sh Mwc + Mwp + Mwe + Mtc + Mvo + Mp−δ EQ 4.1

Where:

Sh = Horizontal wind span (= the sum of 1/2 the lengths of the adjacent 

spans) (ft)

Mwc = Summation of moment loads due to wind on each conductor 

expressed as moment per unit length of conductor (ft-lb/ft)

 = Fow {Σ(WcHc)}cos θ/2 EQ 4.2

Mwp = The moment due to wind on the pole (ft-lb)

= Fow Wp �

2Ct + Cg

Kc

� Hp

2 EQ 4.3

Note: Mwp is calculated for several commonly used poles and tabulated in Exhibit 
RUS Bulletin 1724E–150

Page 7

A at the end of this bulletin.

Mwe = The moment due to wind on the material and equipment attached to 

the pole (ft-lb)

Mtc = Summation of moments due to the tension of the conductors (ft-lb)

 = 2Fot {Σ(TcHc)}sin (θ/2) EQ 4.4

Mvo = The moment due to unbalanced vertical loads (ft-lb)

Mp-δ = The moment due to pole deflection (ft-lb)

And where:

Fow = NESC (Table 253-1) load factor for wind loads

Fot = NESC (Table 253-1) load factor for longitudinal (tension) loads

Hp = Height of pole above ground (ft)

Hc = Height of each conductor attachment above ground line (ft)

Wc = Wind load per unit length of each conductor (1b/ft)

Wp = Wind load per unit area surface ofpole (lb/ft2

)

Tc = Tension in each conductor (lb)

θ = Line angle at pole (degrees)

Ct = Pole circumference at top (in)

Cg = Pole circumference at ground line (in)

Kc = Calculation constant = 72π

b Simplification of Applied Moment Equation. The following force moment

terms of Equation 4.1 can usually be omitted for the following reasons:

(1) Mwe can usually be ignored because the transverse moment due to wind 

on pins, insulators, and the ends of crossarms is typically less than 500 ftlb. However, Mwe should be considered for attached transformers or other 

equipment. Throughout this bulletin it is assumed that no equipment is 

attached to the pole. If equipment is attached to the pole, the designer 

must take the equipment into account in these calculations.

(2) Mtc is zero on tangent poles where the line angle θ = 0 because the sine 

of (θ/2) = 0 and thus Mtc = 2Fot {Σ(TcHc)}sin(θ/2) = 0. The nearly equal 

and opposite longitudinal conductor tensions essentially cancel each other.

(3) Mvo is usually small and can be ignored. RUS standard crossarm 

assemblies are symmetrical (looking in the longitudinal direction). Thus, 

the moments induced in the pole by conductor weights supported by 

crossarms cancel one another. The remaining conductors are attached 

directly to the pole. Therefore, the moment induced in the pole due to 

offset conductor weights is negligible. (Vertical conductor weights alone 

seldom dictate the required pole class.) Nonbalanced pole loads—such as 
RUS Bulletin 1724E–150

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narrow profile assemblies—will affect the pole class and must be taken 

into account in these calculations.

(4) Mp-δ are small ground line moments. Transverse loads cause an 

unguyed pole to deflect a small distance. Vertical loads on the pole times 

this deflection distance cause additional moments to be induced in the 

pole. These additional moments are small compared to the other moments 

of Equation 4.1 and compensated for in Equation 5.2.

c Simplified Equation for Applied Moments. After applying the assumptions and

omissions of Section 4b of this bulletin, Equation 4.1 can be simplified to:

Mg = ShMwc + Mwp + Mtc EQ 4.5

d Example Problem 1: Total Horizontal Moment. Given the following

information and data, calculate the moment (Mg) at the ground line of a 35-foot 

unguyed pole adjacent to a highway crossing span that supports a 3-phase, 

crossarm assembly. The horizontal wind span (Sh) is 300 feet. The line angle (θ) 

is 2 degrees.

(1) Given pole data:

Pole: Southern Yellow Pine (SYP); 35-foot (set 6 foot deep); Class 5

Ct = 19 in Cg = 29 in Hp = 29 ft

(2) Given conductor data:

NESC Heavy Loading District (0oF, 1⁄2" ice, 4 lb/ft2 wind)

3 Primary Conductors: 266.8 18/1 kcmil ACSR (“Waxwing”)

Wc = 0.5363 lb/ft

1 Neutral Conductor: #1/0 6/1 ACSR (“Raven”)

Wc = 0.4660 lb/ft

Conductor attachment heights above ground line:

A phase B phase C phase Neutral 

Hc (ft) = 28.25 29.87 28.25 25.50

Phase conductor design tension: Tc = 2,408 lb DTHL

Neutral conductor design tension: Tc = 1,731 lb DTHL

(3) Given NESC data:

NESC Heavy Loading District; NESC Grade C construction (crossing 

span)

Fow = 2.20 Fot = 1.30 Wp = 4 lb/ft2

(4) The summation of moments per unit length of conductor (Mwc) due to 
RUS Bulletin 1724E–150

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wind on each conductor can be tabulated as follows:

Phase Wc Hc

A (0.5363)(28.25) = 15.15

B (0.5363)(29.87) = 16.02

C (0.5363)(28.25) = 15.15

N (0.4660)(25.50) = 11.88

Total Σ(WcHc) = 58.20

Mwc = Fow{Σ(WcHc)}cos(θ/2) = (2.20)(58.20)(cos 1o) = 128.02 ft-lb/ft

(5) The moment due to wind on the pole is calculated using Equation 4.3 as 

shown below or, alternatively, determined from Table 1 in Exhibit A at the 

end of this bulletin.

Mwp = FowWp �

�2Ct + Cg�

Kc

� Hp

2

Mwp = (2.20)(4) �

�(2)(19) + 29�

72π � (292) = 2,192 ft − lb

(6) The summation of moments due to the tension of each conductor (Mtc) can 

be calculated as follows:

Phase TcHc

A (2,408)(28.25) = 68,026

B (2,408)(29.87) = 71,927

C (2,408)(28.25) = 68,026

N (1,731)(25.50) = 44,141

Total Σ(TcHc) = 252,120

Mtc = 2Fot{Σ(TcHc)}sin(θ/2) = (2)(1.30)(252,120)(sin 1o) = 11,440 ft-lb

(7) The total moment on the pole is calculated using Equation 4.5 as follows:

Mg = ShMwc + Mwp + Mtc

Mg = 300 (ft) x 128.02 (ft-lb/ft) + 2,192 (ft-lb) + 11,440 ft-lb =

52,038 ft-lb
RUS Bulletin 1724E–150

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5 POLE STRENGTH AND REQUIREMENTS

a NESC Strength Requirements of Poles. The NESC requires that a support

structure be able to withstand a load equivalent to all of the expected applied 

loads (multiplied by the appropriate NESC load factors) without exceeding the 

permitted load of the support structure. The permitted load is the designated 

strength of the support structure multiplied by the appropriate NESC strength 

factor of NESC Table 261-1. In this bulletin, “support structure” means a single 

wood distribution pole. For purposes of this bulletin, the NESC strength 

requirement for a support structure means the permitted moment (Mr) for a pole at 

the ground line has to be equal to or exceed the total ground line moment (Mg)

induced in the pole. This relationship is expressed in the following equation:

Mg ≤ Mr EQ 5.1

b Pole Circumference at the Ground Line. The permitted moment (Mr) for a pole at

the ground line can be calculated if the pole’s circumference at the ground line is 

known. However, pole tables tabulate pole circumferences at a fixed distance 

(usually 6 feet as per ANSI 05.1-2008) from the bottom of each pole which may 

not be at the ground line. A pole’s circumference at its ground line, based on its 

circumference 6 feet from its bottom, can be calculated by using the following 

Equation 5.2:

Cg = �

�Lp − Lg�(Cb − Ct)

�Lp − Lb� � + Ct EQ 5.2

Where:

Cg = Pole circumference at ground line (in)

Lp = Length of pole (ft)

Lg = Distance from pole bottom to ground line (ft)

Lb = Distance from pole bottom to classification point per ANSI 05.1-2008

(6 feet)

Cb = Pole circumference at distance Lb from bottom per ANSI 05.1-2008

(in)

Ct = Pole circumference at top (in)

The calculated ground line circumferences (Cg) for several commonly used 

distribution poles are tabulated in Exhibit A at the end of this bulletin.

c Permitted Moment of Pole at the Ground Line. The permitted moment of a

pole at its ground line can he calculated using the following equation:

Mr = Sf Kr Fb Cg

3 EQ 5.3

Where:

Mr = Permitted moment at ground line (ft-lb)
RUS Bulletin 1724E–150

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Sf = NESC strength factor (NESC Table 261-1)

Kr = Calculation constant = 2.64x10-4 (ft/in)

Fb = Designated fiber stress (lb/in2)

The calculated permitted ground line moments (Mr) for several commonly 

used distribution poles are tabulated in Exhibit B at the end of this bulletin.

d Example Problem 2: Determine Pole Resisting Moment. Given the following

pole data, determine if a 35-foot, Class 5, Southern Yellow Pine pole (35-5 SYP) 

is adequate to sustain the total moment of 52,038 ft-lb calculated in Example 

Problem 1 in Section 4d of this bulletin.

(1) Given pole and NESC data:

Cb = 29 in Lp = 35 ft Fb = 8,000 1b/in2

Ct = 19 in Lg = 6 ft Sf = 0.85

Lb = 6 ft

(2) The pole circumference at the ground line (Cg) does not need to be 

calculated for this particular pole height because Lg = Lb = 6 feet and,

therefore, Cg = Cb = 29 in. Normally, for other pole heights and classes, 

Cg needs to be calculated using Equation 5.2 or determined using Exhibit 

A at the end of this bulletin.

(3) The permitted moment at the ground line of a 35-5 SYP pole can be 

calculated using Equation 5.4 as follows or determined using Exhibit B

at the end of this bulletin.

Mr = Sf KrFbCg

3

= (0.85)(0.000264 ft/in)(8,000 lb/in2)(293 in3) 

Mr = 43,783 ft-lb

Since the induced moment of 52,038 ft-lb is greater than the resisting 

moment of a SYP 35-5 pole, a pole of greater strength (higher class) 

needs to be selected to sustain the given loads and conditions of Example 

Problem 1 in Section 4d of this bulletin.

e Repeat Comparison Procedure. If calculations show that a selected pole does not

have adequate strength to sustain the calculated loads, then another, stronger pole 

needs to be selected. The permitted moment (Mr) of any (new) selected pole 

needs to be determined and ascertained that the Mr of the new selected pole is 

greater than the total moment expected to be induced in the pole. Use the 

equations and procedure included in Sections 5a through 5c of this bulletin.

f Moments Above Guy Attachments. Where horizontal loads are applied at some

distance above a guy attachment, it is advisable to check for the pole strength at 
RUS Bulletin 1724E–150

Page 12

the guy attachment location. The portion of a pole below a guy attachment is 

considered to be a strut with only vertical loads applied. The loads above the top 

guy attachment and the strength of the pole at the guy attachment location are 

calculated in the same manner as an unguyed pole with the following two 

modifications.

(1) The moments above a guy attachment can be calculated and summed 

using the same equations and procedure presented in Section 4 of this 

bulletin. However, the distances from the applied loads to the pole’s 

ground line (Hc in Equation 4.2) has to be replaced with the distances from 

the applied loads to the top guy attachment location on the pole.

(2) The circumference of the pole at the top guy attachment location can be 

calculated by replacing the distance Lg in Equation 5.2 with the distance 

from the bottom of the pole to the guy attachment location. Thus, Mr in 

Equation 5.3 becomes the permitted moment at the guy attachment 

location and can be calculated and compared to the calculated moment at 

the guy attachment location.

6 DETERMINATION OF MAXIMUM HORIZONTAL SPANS

a Maximum Horizontal Span. The maximum permitted horizontal span for an

unguyed pole based on a pole’s species, height, and class can be calculated by 

essentially reversing the procedure presented in Sections 4 and 5 of this bulletin. 

Usually the pole height and class are known or given. When unknown, the pole’s 

species should be assumed to be the type with the lowest fiber stress for 

calculation purposes.

b Equation for the Maximum Horizontal Span. The (simplified) equation for the

total ground line moment induced in an unguyed pole with no large or heavy 

equipment attached was presented in Section 4a in this bulletin as:

Mg = ShMwc + Mwp + Mtc EQ 4.5

(1) Equation 4.5 can be rearranged as follows to determine the horizontal 

span (Sh) as a function of the induced moments in the pole:

Sh = �Mg − Mwp − Mtc�

Mwc

ft EQ 6.1

(2) By replacing Mg in Equation 6.1 with Mr , the permitted moment of the 

pole at its ground line, the equation becomes an expression for the 

maximum horizontal span, Sh-max as follows:
RUS Bulletin 1724E–150

Page 13

Sh−max = �Mr − Mwp − Mtc�

Mwc

ft EQ 6.2

The definitions of the moment terms in Equation 6.2 are provided in 

Section 4a and Section 5b of this bulletin. Mtc is zero where the line 

angle θ = 0, because the sine of (θ/2) = 0 and, thus, Mtc = 

2Fot{Σ(TcHc)}sin(θ/2) = 0.

c Example Problem 3: Determination of Maximum Span. Determine the maximum

horizontal span (Sh-max) for a 35-5 SYP pole using the moments calculated in 

Example Problem 1 in Section 4d of this bulletin.

(1) Given (previously calculated) moments:

Mwp = 2,192 ft-lb See Section 4d(5) of this bulletin

Mtc = 11,440 ft-lb See Section 4d(6) of this bulletin

Mwc = 128.02 ft-lb/ft See Section 4d(4) of this bulletin

Mr = 43,783 ft-lb See Section 5d(3) of this bulletin and Section 

6c(2) immediately below.

(2) Maximum horizontal span:

Sh−max = �Mr − Mwp − Mtc�

Mwc

(EQ 6.2)

Sh−max = (43,783 (ft − lb) – 2,192(ft − lb) − 11,440 (ft − lb))

128.02 (ft − lb ⁄ ft)

Sh−max = 235 ft

7 CONTRIBUTORS

The following members of the Overhead Distribution Lines Subcommittee of the 

National Rural Electric Cooperative Association, Transmission and Distribution 

Engineering Committee provided invaluable assistance in preparing this document:

• James Byrne, Poudre Valley REA, Fort Collins, Colo.

• Clive Buttrey, Middle Tennessee EMC, Murfreesboro, Tenn.

• Titus (Ty) Diamond, Flint Energy, Warner Robins, Ga.

• Robby Hamlin, CoServ Electric, Corinth, Texas

• Tom Hoffman, Agralite Electric Cooperative, Benson, Minn.

• Chad Kirkpatrick, Fort Loudoun Electric Cooperative, Vonore, Tenn.

• Kevin Mara, GDS Associates, Inc., Marietta, Ga.

• Ernest Neubauer, Southern Rivers Energy, Barnesville, Ga.

• Matthew O’Shea, STAR Energy Services, LLC, Alexandria, Minn.
RUS Bulletin 1724E–150

Page 14

• Ken Raming, Ozark Electric Cooperative, Mt. Vernon, Mo.

• Terry Rosenthal, Laclede Electric Cooperative, Lebanon, Mo.

• Hank Zarandi, Northern Virginia Electric Cooperative, Gainesville, Va.

• Gerard Moore, Rural Utilities Service, USDA, Washington, D.C.
RUS Bulletin 1724E–150

Exhibit A

Page 1

EXHIBIT A

GROUND LINE MOMENTS CAUSED BY WIND ON WOOD POLES

TABLE 1

NESC Heavy Loading District/Grade C Construction

Loading: Heavy

Grade: C

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 2,430 41.5 2,490 38.0 2,400 42.5 2,520

40 6.0 41.0 3,400 44.0 3,510 40.0 3,370 45.0 3,550

45 6.5 42.8 4,450 45.8 4,580 41.8 4,400 47.2 4,650

50 7.0 44.6 5,650 47.5 5,810 43.6 5,590 49.0 5,900

55 7.5 45.9 6,980 48.8 7,180 44.9 6,910 50.8 7,320

Class 2 25.0

35 6.0 36.5 2,260 38.5 2,310 35.5 2,230 40.0 2,350

40 6.0 38.5 3,170 41.0 3,260 37.5 3,140 42.5 3,310

45 6.5 40.3 4,150 42.8 4,260 39.3 4,100 44.3 4,330

50 7.0 41.6 5,250 44.5 5,410 40.6 5,190 46.0 5,500

55 7.5 42.9 6,490 45.8 6,700 42.0 6,430 47.8 6,830

Class 3 23.0

35 6.0 34.0 2,090 36.0 2,140 33.0 2,060 37.5 2,180

40 6.0 36.0 2,940 38.0 3,010 35.0 2,900 39.5 3,060

45 6.5 37.3 3,830 39.8 3,940 36.8 3,800 41.3 4,010

50 7.0 38.6 4,850 41.6 5,020 38.1 4,820 43.0 5,100

55 7.5 40.0 6,010 42.9 6,210 39.5 5,970 44.3 6,310

Class 4 21.0

35 6.0 31.5 1,920 33.5 1,970 31.0 1,900 34.5 2,000

40 6.0 33.5 2,710 35.5 2,780 32.5 2,670 36.5 2,810

45 6.5 34.8 3,530 36.8 3,620 33.8 3,480 38.3 3,690

50 7.0 36.1 4,480 38.6 4,620 35.2 4,420 39.6 4,670

55 7.5 37.5 5,550 39.9 5,720 36.5 5,490 41.4 5,830

Class 5 19.0

35 6.0 29.0 1,750 31.0 1,800 28.5 1,740 32.0 1,830

40 6.0 31.0 2,470 33.0 2,540 30.0 2,440 34.0 2,580

45 6.5 32.3 3,230 34.3 3,320 31.3 3,190 35.8 3,390

50 7.0 33.7 4,110 35.6 4,220 32.7 4,050 37.1 4,300

Class 6 17.0

35 6.0 27.0 1,590 28.5 1,630 26.5 1,580 30.0 1,670

40 6.0 28.5 2,240 30.5 2,310 28.0 2,220 31.5 2,350

45 6.5 29.8 2,930 31.8 3,020 28.8 2,890 32.8 3,070

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 2

TABLE 2

NESC Heavy Loading District/Grade C Construction—Crossing Spans

Loading: Heavy

Grade: CX

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 3,050 41.5 3,130 38.0 3,020 42.5 3,160

40 6.0 41.0 4,280 44.0 4,410 40.0 4,230 45.0 4,460

45 6.5 42.8 5,590 45.8 5,760 41.8 5,530 47.2 5,840

50 7.0 44.6 7,100 47.5 7,310 43.6 7,030 49.0 7,410

55 7.5 45.9 8,770 48.8 9,030 44.9 8,690 50.8 9,200

Class 2 25.0

35 6.0 36.5 2,840 38.5 2,900 35.5 2,800 40.0 2,950

40 6.0 38.5 3,990 41.0 4,100 37.5 3,940 42.5 4,170

45 6.5 40.3 5,210 42.8 5,350 39.3 5,160 44.3 5,440

50 7.0 41.6 6,600 44.5 6,810 40.6 6,520 46.0 6,910

55 7.5 42.9 8,160 45.8 8,420 42.0 8,080 47.8 8,590

Class 3 23.0

35 6.0 34.0 2,620 36.0 2,690 33.0 2,590 37.5 2,740

40 6.0 36.0 3,690 38.0 3,780 35.0 3,650 39.5 3,850

45 6.5 37.3 4,810 39.8 4,950 36.8 4,780 41.3 5,040

50 7.0 38.6 6,090 41.6 6,300 38.1 6,060 43.0 6,410

55 7.5 40.0 7,550 42.9 7,810 39.5 7,510 44.3 7,930

Class 4 21.0

35 6.0 31.5 2,410 33.5 2,480 31.0 2,390 34.5 2,510

40 6.0 33.5 3,400 35.5 3,490 32.5 3,360 36.5 3,540

45 6.5 34.8 4,430 36.8 4,550 33.8 4,380 38.3 4,630

50 7.0 36.1 5,630 38.6 5,800 35.2 5,560 39.6 5,870

55 7.5 37.5 6,980 39.9 7,190 36.5 6,900 41.4 7,320

Class 5 19.0

35 6.0 29.0 2,200 31.0 2,260 28.5 2,180 32.0 2,300

40 6.0 31.0 3,110 33.0 3,200 30.0 3,060 34.0 3,240

45 6.5 32.3 4,060 34.3 4,170 31.3 4,000 35.8 4,260

50 7.0 33.7 5,160 35.6 5,300 32.7 5,090 37.1 5,410

Class 6 17.0

35 6.0 27.0 2,000 28.5 2,050 26.5 1,980 30.0 2,100

40 6.0 28.5 2,820 30.5 2,910 28.0 2,790 31.5 2,950

45 6.5 29.8 3,690 31.8 3,800 28.8 3,630 32.8 3,860

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 3

TABLE 3

NESC Heavy Loading District/Grade B Construction

Loading: Heavy

Grade: B

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 3,460 41.5 3,560 38.0 3,430 42.5 3,590

40 6.0 41.0 4,860 44.0 5,010 40.0 4,810 45.0 5,060

45 6.5 42.8 6,350 45.8 6,540 41.8 6,280 47.2 6,640

50 7.0 44.6 8,060 47.5 8,300 43.6 7,980 49.0 8,420

55 7.5 45.9 9,970 48.8 10,260 44.9 9,870 50.8 10,450

Class 2 25.0

35 6.0 36.5 3,220 38.5 3,300 35.5 3,180 40.0 3,350

40 6.0 38.5 4,530 41.0 4,660 37.5 4,480 42.5 4,730

45 6.5 40.3 5,920 42.8 6,080 39.3 5,860 44.3 6,180

50 7.0 41.6 7,490 44.5 7,730 40.6 7,410 46.0 7,850

55 7.5 42.9 9,270 45.8 9,570 42.0 9,180 47.8 9,760

Class 3 23.0

35 6.0 34.0 2,980 36.0 3,050 33.0 2,940 37.5 3,110

40 6.0 36.0 4,200 38.0 4,300 35.0 4,140 39.5 4,370

45 6.5 37.3 5,460 39.8 5,630 36.8 5,430 41.3 5,720

50 7.0 38.6 6,920 41.6 7,160 38.1 6,880 43.0 7,280

55 7.5 40.0 8,580 42.9 8,870 39.5 8,530 44.3 9,010

Class 4 21.0

35 6.0 31.5 2,740 33.5 2,810 31.0 2,720 34.5 2,850

40 6.0 33.5 3,860 35.5 3,970 32.5 3,810 36.5 4,020

45 6.5 34.8 5,040 36.8 5,170 33.8 4,970 38.3 5,270

50 7.0 36.1 6,390 38.6 6,590 35.2 6,310 39.6 6,670

55 7.5 37.5 7,930 39.9 8,170 36.5 7,840 41.4 8,320

Class 5 19.0

35 6.0 29.0 2,500 31.0 2,570 28.5 2,480 32.0 2,610

40 6.0 31.0 3,530 33.0 3,630 30.0 3,480 34.0 3,680

45 6.5 32.3 4,610 34.3 4,740 31.3 4,550 35.8 4,840

50 7.0 33.7 5,860 35.6 6,020 32.7 5,780 37.1 6,140

Class 6 17.0

35 6.0 27.0 2,270 28.5 2,330 26.5 2,250 30.0 2,380

40 6.0 28.5 3,200 30.5 3,300 28.0 3,170 31.5 3,350

45 6.5 29.8 4,190 31.8 4,320 28.8 4,120 32.8 4,380

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 4

TABLE 4

NESC Medium Loading District/Grade C Construction

Loading: Medium

Grade: C

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 2,430 41.5 2,490 38.0 2,400 42.5 2,520

40 6.0 41.0 3,400 44.0 3,510 40.0 3,370 45.0 3,550

45 6.5 42.8 4,450 45.8 4,580 41.8 4,400 47.2 4,650

50 7.0 44.6 5,650 47.5 5,810 43.6 5,590 49.0 5,900

55 7.5 45.9 6,980 48.8 7,180 44.9 6,910 50.8 7,320

Class 2 25.0

35 6.0 36.5 2,260 38.5 2,310 35.5 2,230 40.0 2,350

40 6.0 38.5 3,170 41.0 3,260 37.5 3,140 42.5 3,310

45 6.5 40.3 4,150 42.8 4,260 39.3 4,100 44.3 4,330

50 7.0 41.6 5,250 44.5 5,410 40.6 5,190 46.0 5,500

55 7.5 42.9 6,490 45.8 6,700 42.0 6,430 47.8 6,830

Class 3 23.0

35 6.0 34.0 2,090 36.0 2,140 33.0 2,060 37.5 2,180

40 6.0 36.0 2,940 38.0 3,010 35.0 2,900 39.5 3,060

45 6.5 37.3 3,830 39.8 3,940 36.8 3,800 41.3 4,010

50 7.0 38.6 4,850 41.6 5,020 38.1 4,820 43.0 5,100

55 7.5 40.0 6,010 42.9 6,210 39.5 5,970 44.3 6,310

Class 4 21.0

35 6.0 31.5 1,920 33.5 1,970 31.0 1,900 34.5 2,000

40 6.0 33.5 2,710 35.5 2,780 32.5 2,670 36.5 2,810

45 6.5 34.8 3,530 36.8 3,620 33.8 3,480 38.3 3,690

50 7.0 36.1 4,480 38.6 4,620 35.2 4,420 39.6 4,670

55 7.5 37.5 5,550 39.9 5,720 36.5 5,490 41.4 5,830

Class 5 19.0

35 6.0 29.0 1,750 31.0 1,800 28.5 1,740 32.0 1,830

40 6.0 31.0 2,470 33.0 2,540 30.0 2,440 34.0 2,580

45 6.5 32.3 3,230 34.3 3,320 31.3 3,190 35.8 3,390

50 7.0 33.7 4,110 35.6 4,220 32.7 4,050 37.1 4,300

Class 6 17.0

35 6.0 27.0 1,590 28.5 1,630 26.5 1,580 30.0 1,670

40 6.0 28.5 2,240 30.5 2,310 28.0 2,220 31.5 2,350

45 6.5 29.8 2,930 31.8 3,020 28.8 2,890 32.8 3,070

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 5

TABLE 5

NESC Medium Loading District/Grade C Construction—Crossing Spans

Loading: Medium

Grade: CX

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 3,050 41.5 3,130 38.0 3,020 42.5 3,160

40 6.0 41.0 4,280 44.0 4,410 40.0 4,230 45.0 4,460

45 6.5 42.8 5,590 45.8 5,760 41.8 5,530 47.2 5,840

50 7.0 44.6 7,100 47.5 7,310 43.6 7,030 49.0 7,410

55 7.5 45.9 8,770 48.8 9,030 44.9 8,690 50.8 9,200

Class 2 25.0

35 6.0 36.5 2,840 38.5 2,900 35.5 2,800 40.0 2,950

40 6.0 38.5 3,990 41.0 4,100 37.5 3,940 42.5 4,170

45 6.5 40.3 5,210 42.8 5,350 39.3 5,160 44.3 5,440

50 7.0 41.6 6,600 44.5 6,810 40.6 6,520 46.0 6,910

55 7.5 42.9 8,160 45.8 8,420 42.0 8,080 47.8 8,590

Class 3 23.0

35 6.0 34.0 2,620 36.0 2,690 33.0 2,590 37.5 2,740

40 6.0 36.0 3,690 38.0 3,780 35.0 3,650 39.5 3,850

45 6.5 37.3 4,810 39.8 4,950 36.8 4,780 41.3 5,040

50 7.0 38.6 6,090 41.6 6,300 38.1 6,060 43.0 6,410

55 7.5 40.0 7,550 42.9 7,810 39.5 7,510 44.3 7,930

Class 4 21.0

35 6.0 31.5 2,410 33.5 2,480 31.0 2,390 34.5 2,510

40 6.0 33.5 3,400 35.5 3,490 32.5 3,360 36.5 3,540

45 6.5 34.8 4,430 36.8 4,550 33.8 4,380 38.3 4,630

50 7.0 36.1 5,630 38.6 5,800 35.2 5,560 39.6 5,870

55 7.5 37.5 6,980 39.9 7,190 36.5 6,900 41.4 7,320

Class 5 19.0

35 6.0 29.0 2,200 31.0 2,260 28.5 2,180 32.0 2,300

40 6.0 31.0 3,110 33.0 3,200 30.0 3,060 34.0 3,240

45 6.5 32.3 4,060 34.3 4,170 31.3 4,000 35.8 4,260

50 7.0 33.7 5,160 35.6 5,300 32.7 5,090 37.1 5,410

Class 6 17.0

35 6.0 27.0 2,000 28.5 2,050 26.5 1,980 30.0 2,100

40 6.0 28.5 2,820 30.5 2,910 28.0 2,790 31.5 2,950

45 6.5 29.8 3,690 31.8 3,800 28.8 3,630 32.8 3,860

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 6

TABLE 6

NESC Medium Loading District/Grade B Construction

Loading: Medium

Grade: B

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 3,460 41.5 3,560 38.0 3,430 42.5 3,590

40 6.0 41.0 4,860 44.0 5,010 40.0 4,810 45.0 5,060

45 6.5 42.8 6,350 45.8 6,540 41.8 6,280 47.2 6,640

50 7.0 44.6 8,060 47.5 8,300 43.6 7,980 49.0 8,420

55 7.5 45.9 9,970 48.8 10,260 44.9 9,870 50.8 10,450

Class 2 25.0

35 6.0 36.5 3,220 38.5 3,300 35.5 3,180 40.0 3,350

40 6.0 38.5 4,530 41.0 4,660 37.5 4,480 42.5 4,730

45 6.5 40.3 5,920 42.8 6,080 39.3 5,860 44.3 6,180

50 7.0 41.6 7,490 44.5 7,730 40.6 7,410 46.0 7,850

55 7.5 42.9 9,270 45.8 9,570 42.0 9,180 47.8 9,760

Class 3 23.0

35 6.0 34.0 2,980 36.0 3,050 33.0 2,940 37.5 3,110

40 6.0 36.0 4,200 38.0 4,300 35.0 4,140 39.5 4,370

45 6.5 37.3 5,460 39.8 5,630 36.8 5,430 41.3 5,720

50 7.0 38.6 6,920 41.6 7,160 38.1 6,880 43.0 7,280

55 7.5 40.0 8,580 42.9 8,870 39.5 8,530 44.3 9,010

Class 4 21.0

35 6.0 31.5 2,740 33.5 2,810 31.0 2,720 34.5 2,850

40 6.0 33.5 3,860 35.5 3,970 32.5 3,810 36.5 4,020

45 6.5 34.8 5,040 36.8 5,170 33.8 4,970 38.3 5,270

50 7.0 36.1 6,390 38.6 6,590 35.2 6,310 39.6 6,670

55 7.5 37.5 7,930 39.9 8,170 36.5 7,840 41.4 8,320

Class 5 19.0

35 6.0 29.0 2,500 31.0 2,570 28.5 2,480 32.0 2,610

40 6.0 31.0 3,530 33.0 3,630 30.0 3,480 34.0 3,680

45 6.5 32.3 4,610 34.3 4,740 31.3 4,550 35.8 4,840

50 7.0 33.7 5,860 35.6 6,020 32.7 5,780 37.1 6,140

Class 6 17.0

35 6.0 27.0 2,270 28.5 2,330 26.5 2,250 30.0 2,380

40 6.0 28.5 3,200 30.5 3,300 28.0 3,170 31.5 3,350

45 6.5 29.8 4,190 31.8 4,320 28.8 4,120 32.8 4,380

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 7

TABLE 7

NESC Light Loading District/Grade C Construction

Loading: Light

Grade: C

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 5,450 41.5 5,600 38.0 5,390 42.5 5,660

40 6.0 41.0 7,650 44.0 7,890 40.0 7,570 45.0 7,970

45 6.5 42.8 10,000 45.8 10,300 41.8 9,890 47.2 10,450

50 7.0 44.6 12,700 47.5 13,080 43.6 12,570 49.0 13,260

55 7.5 45.9 15,700 48.8 16,160 44.9 15,550 50.8 16,460

Class 2 25.0

35 6.0 36.5 5,070 38.5 5,190 35.5 5,010 40.0 5,280

40 6.0 38.5 7,130 41.0 7,330 37.5 7,050 42.5 7,450

45 6.5 40.3 9,320 42.8 9,580 39.3 9,220 44.3 9,730

50 7.0 41.6 11,800 44.5 12,180 40.6 11,670 46.0 12,370

55 7.5 42.9 14,610 45.8 15,060 42.0 14,450 47.8 15,370

Class 3 23.0

35 6.0 34.0 4,690 36.0 4,810 33.0 4,630 37.5 4,890

40 6.0 36.0 6,610 38.0 6,770 35.0 6,520 39.5 6,890

45 6.5 37.3 8,600 39.8 8,860 36.8 8,550 41.3 9,010

50 7.0 38.6 10,900 41.6 11,280 38.1 10,840 43.0 11,470

55 7.5 40.0 13,510 42.9 13,970 39.5 13,430 44.3 14,200

Class 4 21.0

35 6.0 31.5 4,310 33.5 4,430 31.0 4,280 34.5 4,480

40 6.0 33.5 6,080 35.5 6,240 32.5 6,000 36.5 6,320

45 6.5 34.8 7,930 36.8 8,140 33.8 7,830 38.3 8,290

50 7.0 36.1 10,070 38.6 10,380 35.2 9,940 39.6 10,510

55 7.5 37.5 12,490 39.9 12,870 36.5 12,340 41.4 13,100

Class 5 19.0

35 6.0 29.0 3,930 31.0 4,050 28.5 3,900 32.0 4,100

40 6.0 31.0 5,560 33.0 5,720 30.0 5,480 34.0 5,800

45 6.5 32.3 7,260 34.3 7,470 31.3 7,160 35.8 7,620

50 7.0 33.7 9,230 35.6 9,480 32.7 9,110 37.1 9,670

Class 6 17.0

35 6.0 27.0 3,580 28.5 3,660 26.5 3,550 30.0 3,750

40 6.0 28.5 5,040 30.5 5,200 28.0 5,000 31.5 5,280

45 6.5 29.8 6,590 31.8 6,800 28.8 6,490 32.8 6,900

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 8

TABLE 8

NESC Light Loading District/Grade C Construction—Crossing Spans

Loading: Light

Grade: CX

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 6,850 41.5 7,040 38.0 6,780 42.5 7,110

40 6.0 41.0 9,620 44.0 9,920 40.0 9,520 45.0 10,020

45 6.5 42.8 12,560 45.8 12,950 41.8 12,440 47.2 13,140

50 7.0 44.6 15,960 47.5 16,440 43.6 15,800 49.0 16,670

55 7.5 45.9 19,740 48.8 20,310 44.9 19,540 50.8 20,690

Class 2 25.0

35 6.0 36.5 6,370 38.5 6,520 35.5 6,300 40.0 6,630

40 6.0 38.5 8,960 41.0 9,210 37.5 8,860 42.5 9,370

45 6.5 40.3 11,720 42.8 12,040 39.3 11,590 44.3 12,230

50 7.0 41.6 14,830 44.5 15,310 40.6 14,670 46.0 15,540

55 7.5 42.9 18,360 45.8 18,930 42.0 18,170 47.8 19,320

Class 3 23.0

35 6.0 34.0 5,890 36.0 6,040 33.0 5,820 37.5 6,150

40 6.0 36.0 8,300 38.0 8,510 35.0 8,200 39.5 8,660

45 6.5 37.3 10,810 39.8 11,140 36.8 10,750 41.3 11,330

50 7.0 38.6 13,700 41.6 14,180 38.1 13,620 43.0 14,420

55 7.5 40.0 16,980 42.9 17,560 39.5 16,890 44.3 17,840

Class 4 21.0

35 6.0 31.5 5,420 33.5 5,560 31.0 5,380 34.5 5,640

40 6.0 33.5 7,640 35.5 7,850 32.5 7,540 36.5 7,950

45 6.5 34.8 9,970 36.8 10,230 33.8 9,840 38.3 10,420

50 7.0 36.1 12,650 38.6 13,050 35.2 12,500 39.6 13,210

55 7.5 37.5 15,700 39.9 16,180 36.5 15,510 41.4 16,470

Class 5 19.0

35 6.0 29.0 4,940 31.0 5,080 28.5 4,900 32.0 5,160

40 6.0 31.0 6,990 33.0 7,190 30.0 6,890 34.0 7,290

45 6.5 32.3 9,130 34.3 9,390 31.3 9,000 35.8 9,580

50 7.0 33.7 11,600 35.6 11,920 32.7 11,450 37.1 12,160

Class 6 17.0

35 6.0 27.0 4,500 28.5 4,610 26.5 4,460 30.0 4,720

40 6.0 28.5 6,330 30.5 6,530 28.0 6,280 31.5 6,630

45 6.5 29.8 8,290 31.8 8,540 28.8 8,160 32.8 8,670

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit A

Page 9

TABLE 9

NESC Light Loading District/Grade B Construction

Loading: Light

Grade: B

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

Length GL CT CGL MWP CGL MWP CGL MWP CGL MWP

(ft) (ft) (in) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb) (in) (ft-lb)

Class 1 27.0

35 6.0 39.0 7,780 41.5 7,990 38.0 7,700 42.5 8,080

40 6.0 41.0 10,930 44.0 11,270 40.0 10,810 45.0 11,390

45 6.5 42.8 14,280 45.8 14,710 41.8 14,130 47.2 14,930

50 7.0 44.6 18,140 47.5 18,680 43.6 17,960 49.0 18,950

55 7.5 45.9 22,430 48.8 23,080 44.9 22,210 50.8 23,510

Class 2 25.0

35 6.0 36.5 7,240 38.5 7,410 35.5 7,160 40.0 7,530

40 6.0 38.5 10,180 41.0 10,470 37.5 10,070 42.5 10,640

45 6.5 40.3 13,320 42.8 13,680 39.3 13,170 44.3 13,900

50 7.0 41.6 16,850 44.5 17,390 40.6 16,680 46.0 17,660

55 7.5 42.9 20,860 45.8 21,520 42.0 20,640 47.8 21,950

Class 3 23.0

35 6.0 34.0 6,700 36.0 6,860 33.0 6,610 37.5 6,990

40 6.0 36.0 9,430 38.0 9,660 35.0 9,320 39.5 9,840

45 6.5 37.3 12,290 39.8 12,650 36.8 12,220 41.3 12,870

50 7.0 38.6 15,570 41.6 16,110 38.1 15,480 43.0 16,380

55 7.5 40.0 19,300 42.9 19,950 39.5 19,190 44.3 20,280

Class 4 21.0

35 6.0 31.5 6,150 33.5 6,320 31.0 6,110 34.5 6,400

40 6.0 33.5 8,690 35.5 8,920 32.5 8,570 36.5 9,030

45 6.5 34.8 11,330 36.8 11,620 33.8 11,190 38.3 11,840

50 7.0 36.1 14,380 38.6 14,830 35.2 14,200 39.6 15,010

55 7.5 37.5 17,840 39.9 18,390 36.5 17,630 41.4 18,710

Class 5 19.0

35 6.0 29.0 5,610 31.0 5,780 28.5 5,570 32.0 5,860

40 6.0 31.0 7,940 33.0 8,170 30.0 7,820 34.0 8,280

45 6.5 32.3 10,370 34.3 10,670 31.3 10,230 35.8 10,880

50 7.0 33.7 13,180 35.6 13,540 32.7 13,010 37.1 13,810

Class 6 17.0

35 6.0 27.0 5,110 28.5 5,230 26.5 5,070 30.0 5,360

40 6.0 28.5 7,190 30.5 7,420 28.0 7,130 31.5 7,540

45 6.5 29.8 9,420 31.8 9,710 28.8 9,270 32.8 9,850

GL = Distance from bottom of pole to ground line (ft)

CT = Circumference of pole at top (inches)

CGL = Circumference of pole at ground line (inches)

MWP = Ground line moment induced by wind on pole (ft-lbs)
RUS Bulletin 1724E–150

Exhibit B

Page 1

EXHIBIT B

PERMITTED3F

4 MOMENTS AT GROUND LINE OF WOOD POLES

TABLE 10

NESC Grade C Construction

Grade: C

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

 DFS = 8,000 6,600 8,400 6,000 

Length GL MR-GL MR-GL MR-GL MR-GL

(ft) (ft) (ft-lb) (ft-lb) (ft-lb) (ft-lb)

Class 1 

35 6.0 106,500 105,900 103,500 103,400

40 6.0 123,800 126,200 120,700 122,700

45 6.5 140,700 141,900 137,800 142,000

50 7.0 159,200 159,000 156,400 158,300

55 7.5 173,700 172,300 171,100 176,000

Class 2 

35 6.0 87,300 84,600 84,400 86,200

40 6.0 102,500 102,100 99,500 103,400

45 6.5 117,600 115,900 114,600 116,700

50 7.0 129,400 131,000 126,500 131,200

55 7.5 142,100 142,700 139,300 146,900

Class 3 

35 6.0 70,600 69,100 67,800 71,100

40 6.0 83,800 81,300 80,900 83,000

45 6.5 93,300 93,300 94,100 94,600

50 7.0 103,600 106,400 104,700 107,400

55 7.5 114,600 116,800 116,000 117,300

Class 4 

35 6.0 56,200 55,700 56,200 55,300

40 6.0 67,500 66,300 64,800 65,500

45 6.5 75,800 73,800 73,100 75,500

50 7.0 84,800 85,200 82,100 83,500

55 7.5 94,600 94,100 91,800 95,300

Class 5 

35 6.0 43,800 44,200 43,700 44,200

40 6.0 53,500 53,300 50,900 53,000

45 6.5 60,700 59,800 58,100 61,700

50 7.0 68,500 66,900 65,800 68,700

Class 6 

35 6.0 35,400 34,300 35,100 36,400

40 6.0 41,600 42,100 41,400 42,100

45 6.5 47,700 47,700 45,300 47,500

GL = Distance from bottom of pole to ground line (ft)

MR-GL = Resistive moment of pole at ground line (ft-lb)

DFS = Designated fiber stress of poles (lb/in2)

4 “Permitted” means strength factor of NESC Table 261-1 has been factored in values of MR-GL

 
RUS Bulletin 1724E–150

Exhibit B

Page 2

TABLE 11

NESC Grade C Construction—Crossing Spans

Grade: CX

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

 DFS = 8,000 6,600 8,400 6,000 

Length GL MR-GL MR-GL MR-GL MR-GL

(ft) (ft) (ft-lb) (ft-lb) (ft-lb) (ft-lb)

Class 1 

35 6.0 106,500 105,900 103,500 103,400

40 6.0 123,800 126,200 120,700 122,700

45 6.5 140,700 141,900 137,800 142,000

50 7.0 159,200 159,000 156,400 158,300

55 7.5 173,700 172,300 171,100 176,000

Class 2 

35 6.0 87,300 84,600 84,400 86,200

40 6.0 102,500 102,100 99,500 103,400

45 6.5 117,600 115,900 114,600 116,700

50 7.0 129,400 131,000 126,500 131,200

55 7.5 142,100 142,700 139,300 146,900

Class 3 

35 6.0 70,600 69,100 67,800 71,100

40 6.0 83,800 81,300 80,900 83,000

45 6.5 93,300 93,300 94,100 94,600

50 7.0 103,600 106,400 104,700 107,400

55 7.5 114,600 116,800 116,000 117,300

Class 4 

35 6.0 56,200 55,700 56,200 55,300

40 6.0 67,500 66,300 64,800 65,500

45 6.5 75,800 73,800 73,100 75,500

50 7.0 84,800 85,200 82,100 83,500

55 7.5 94,600 94,100 91,800 95,300

Class 5 

35 6.0 43,800 44,200 43,700 44,200

40 6.0 53,500 53,300 50,900 53,000

45 6.5 60,700 59,800 58,100 61,700

50 7.0 68,500 66,900 65,800 68,700

Class 6 

35 6.0 35,400 34,300 35,100 36,400

40 6.0 41,600 42,100 41,400 42,100

45 6.5 47,700 47,700 45,300 47,500

GL = Distance from bottom of pole to ground line (ft)

MR-GL = Resistive moment of pole at ground line (ft-lb)

DFS = Designated fiber stress of poles (lb/in2

)
RUS Bulletin 1724E–150

Exhibit B

Page 3

TABLE 12

NESC Grade B Construction

Grade: B

Southern Yellow Lodgepole Pine Western

Pine & Douglas Fir & Red Pine Western Larch Red Cedar

 DFS = 8,000 6,600 8,400 6,000 

Length GL MR-GL MR-GL MR-GL MR-GL

(ft) (ft) (ft-lb) (ft-lb) (ft-lb) (ft-lb)

Class 1 

35 6.0 81,500 81,000 79,100 79,100

40 6.0 94,700 96,500 92,300 93,900

45 6.5 107,600 108,500 105,400 108,600

50 7.0 121,800 121,600 119,600 121,100

55 7.5 132,800 131,800 130,800 134,600

Class 2 

35 6.0 66,800 64,700 64,500 65,900

40 6.0 78,400 78,100 76,100 79,100

45 6.5 89,900 88,700 87,600 89,300

50 7.0 99,000 100,200 96,800 100,300

55 7.5 108,700 109,200 106,600 112,400

Class 3 

35 6.0 54,000 52,900 51,900 54,300

40 6.0 64,100 62,200 61,900 63,500

45 6.5 71,400 71,400 72,000 72,400

50 7.0 79,200 81,400 80,100 82,100

55 7.5 87,700 89,300 88,700 89,700

Class 4 

35 6.0 43,000 42,600 43,000 42,300

40 6.0 51,700 50,700 49,500 50,100

45 6.5 58,000 56,500 55,900 57,800

50 7.0 64,900 65,100 62,800 63,800

55 7.5 72,300 72,000 70,200 72,900

Class 5 

35 6.0 33,500 33,800 33,400 33,800

40 6.0 40,900 40,800 39,000 40,500

45 6.5 46,400 45,800 44,400 47,200

50 7.0 52,400 51,200 50,400 52,500

Class 6 

35 6.0 27,100 26,300 26,900 27,800

40 6.0 31,800 32,200 31,700 32,200

45 6.5 36,500 36,500 34,600 36,400

GL = Distance from bottom of pole to ground line (ft)

MR-GL = Resistive moment of pole at ground line (ft-lb)

DFS = Designated fiber stress of poles (lb/in2

)