Version 4.10.00 August 2007

USERS GUIDE

ELECTRICAL DISTRIBUTION AND TRANSMISSION SYSTEMS ANALYSES AND DESIGN PROGRAMS

CABLE PULLING TENSIONS

EDSA Micro Corporation 16870 West Bernardo Drive, Suite 330

San Diego, California 92127 USA

©Copyright 2007

All Rights Reserved

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EDSA MICRO CORPORATION

WARRANTY INFORMATION

There is no warranty, implied or otherwise, on EDSA software. EDSA software is licensed to you as is. This program license provides a ninety (90) day limited warranty on the diskette that contains the program. This, the EDSA User’s Guide, is not meant to alter the warranty situation described above. That is, the content of this document is not intended to, and does not, constitute a warranty of any sort, including warranty of merchantability or fitness for any particular purpose on your EDSA software package. EDSA Micro Corporation reserves the right to revise and make changes to this User's Guide and to the EDSA software without obligation to notify any person of, or provide any person with, such revision or change. EDSA programs come with verification and validation of methodology of calculation based on EDSA Micro Corporation's in-house software development standards. EDSA performs longhand calculation and checks the programs’ results against published samples. However, we do not guarantee, or warranty, any program outputs, results, or conclusions reached from data generated by any programs, which are all sold "as is". Since the meaning of QA/QC and the verification and validation of a program methodology are domains of vast interpretation, users are encouraged to perform their own in-house verification and validation based on their own in-house quality assurance, quality control policies and standards. Such operations - performed at the user's expense - will meet the user's specific needs. EDSA Micro Corporation does not accept, or acknowledge, purchase instructions based on a buyer's QA/QC and/or a buyer's verification and validation standards. Therefore, purchase orders instructions are considered to be uniquely based on EDSA's own QA/QC verification and validation standards and test systems.

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Table of Contents

I. FOREWORD ....................................................................................................................................................1

II. CABLE PULLING CAPABILITIES, FUNCTIONS AND FEATURES ........................................................1

III. INTRODUCTION ............................................................................................................................................1

III. CABLE PULLING TENSIONS AND SIDEWALL PRESSURES .................................................................2

IV. CABLE CONFIGURATIONS .........................................................................................................................2

V. CABLE DATA .................................................................................................................................................2

VI. DESIGN CRITERIA ........................................................................................................................................3

VII. COEFFICIENT OF FRICTION........................................................................................................................3

VIII. PROFILES ........................................................................................................................................................3

IX. USE OF THE KEYBOARD.............................................................................................................................3

X. LIBRARIES......................................................................................................................................................3

XI. CABLE REEL BACK PRESSURE..................................................................................................................3

XII. METHOD OF CALCULATION ......................................................................................................................4

XIII. TECHNICAL PARAMETERS.........................................................................................................................4

XIV. PROGRAM FEATURES................................................................................................................................16

14.1 USING THE PROGRAM'S BUILT-IN HELP FACILITY...................................................................17

14.2 MAIN MENU ITEMS ...........................................................................................................................18

14.3 PROGRAM SUBMENU ENTRIES ......................................................................................................19

XV. REFERENCES ...............................................................................................................................................21

XVI. GLOSSARY OF TERMS AND DEFINITIONS............................................................................................21

XVII. ADDITIONAL NOTES..................................................................................................................................23

APPENDIX A: Cable Pulling Tutorial.................................................................................................................... A-1

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Table of Figures Figure 1..........................................................................................................................................................................2 Figure 2..........................................................................................................................................................................2 Figure 3..........................................................................................................................................................................2 Figure 4..........................................................................................................................................................................2 Figure 5..........................................................................................................................................................................7 Figure 6..........................................................................................................................................................................8 Figure 7..........................................................................................................................................................................8 Figure 8..........................................................................................................................................................................9 Figure 9........................................................................................................................................................................10 Figure 10......................................................................................................................................................................11 Figure 11......................................................................................................................................................................12 Figure 12......................................................................................................................................................................13 Figure 13......................................................................................................................................................................15 Figure 14......................................................................................................................................................................16

Table of Tables Table A: SWBP Equations ....................................................................................................................................... A-2

Table B: Recommended Maximum Sidewall Bearing Pressures ............................................................................. A-2

©Copyright 2007

All Rights Reserved

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I. FOREWORD This discussion assumes the user is a Professional Engineer familiar with the issues surrounding

cable pulling problems. The program's assumptions and definitions are consistent with standard cable tension and sidewall pressure calculation techniques. This document should be used in conjunction with other texts on the subject, and should not be used as the user's sole source of information on cable pulling analysis.

Determination of validity of the results, and whether the program is applicable to a system,

is solely the responsibility of the user. This program is undergoing continuous development and refinement. As with all our products,

EDSA is committed to making the Cable Pulling Tensions & Sidewall Pressures program as current, comprehensive and as easy to use as possible. Any comments, suggestions or errors encountered in either the results or documentation should be immediately brought to EDSA's attention.

II. CABLE PULLING CAPABILITIES, FUNCTIONS AND FEATURES

Front, Top, Side Views User control of graphics Single Cable, Three Cables Triangular, Three Cables Cradled, Four Cables Diamond Complete Library of Cables 3-D Isometric View Pull different size cables Pull multiple cables Forward and reverse tension calculation Sidewall pressure calculation PASS/FAIL Option Vertical and horizontal levels

III. INTRODUCTION The sidewall bearing pressure and pulling tension that cables undergo during installation

determine the lengths of cable and splices. Construction field professionals need to know that the pressures and tensions the cables are submitted to do not damage the cable. Electrical contractors and installers of cables seek to make the longest un-spliced runs possible because splices are costly and are frequently the source of circuit failures. Pulling lengths of cables determine the number and location of splices, electrical manholes, and pull boxes.

The maximum length of cable, which may be safely pulled into a duct or conduit, depends on the

following factors:

Type of cable pulling lubricant; Coefficient of friction of duct or conduit; Size, weight and type of conductor;

Maximum allowable sidewall pressure and maximum pulling strain on the conductors and/or sheath; Bend angle and directions (horizontal or vertical), number of bends and radius of bends;

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Method of pulling cable (basket weave grip, pulling eyes, etc.); Size of conduit and percentage of conduit fill; Number and configuration of cables in the conduit.

III. CABLE PULLING TENSIONS AND SIDEWALL PRESSURES This program has been written for professional design engineers. EDSA believes that pulling

tension and sidewall pressure should be calculated at the time of design and not at the time of installation. A review of the faults, fires and electrical systems shutdowns indicates that many of these failures are directly attributable to the cable damage that occurred during installation. The magnitude of the pulling tension and sidewall pressure exerted on cables during installation plays a major role in the health of a cable. If pressure is exceeded above the cable allowable limits, the tension and/or sidewall pressure could permanently damage the cable insulation. Mechanical damage (unless severe) usually remains undetected until a breakdown occurs in the insulation system, which is often due to aging and subsequent moisture penetration/carbonization.

Cable pulling calculations should be done during the design stage of a raceway-feeder, or cable

installation, to find the values for expected tension when pulling cable, and also find the pulling force caused by sidewall pressure on the cable pulled around the bends. The main parameters that must be considered in such calculations are: number and diameter of cable, type of cable, the coefficient of dynamic friction between cable and conduit, type of conduit, and bending radii. The results of the calculations should be within the allowable limits as established by the cable manufacturers.

IV. CABLE CONFIGURATIONS The manner in which the cables are installed in the raceway plays a very important role in the

determination of pulling tension and sidewall pressure. The cables in this program are defined as: Single Cable

Three Cables Triangular Three Cables Cradled Four Cables Diamond Figure 1 Figure 2 Figure 3 Figure 4 V. CABLE DATA Any size, type, insulation category, or voltage level can be entered. All data entered are for single

cable and the program extends the information for the number of conductors pulled.

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VI. DESIGN CRITERIA The user can input the maximum design sidewall pressure in pounds per foot and the maximum

design tension in pounds. The Cable Pulling Tensions program will give warnings if during the pull sidewall pressure and/or the tension exceed the user defined maximum safe limits.

VII. COEFFICIENT OF FRICTION The user should enter the coefficient of friction for both high and low sidewall pressure

calculations. The user should also specify the pulling compound, or select a compound from the program's lubricating compound library.

VIII. PROFILES EDSA Cable Pulling program permits the user to input 99 sections in every profile. The number of

profiles is limited only by the user's hard disk capacity. IX. USE OF THE KEYBOARD This program makes use of FUNCTION KEYS 1-10 and ESC. X. LIBRARIES There are three libraries available: A) The Pulling Compound Data, B) Cable Data / Feeder

Library and C) Raceway Data. The user may add, modify and delete entries in the libraries. A) THE PULLING COMPOUND LIBRARY The Pulling Compound Data Library includes the definition of various types of pulling

lubricants with corresponding coefficients of friction for high and low sidewall tensions. The compound type may be selected with the arrow key, and transferred into the profile screen by pressing the ENTER key. The entries in the library can be modified to suit the user's preference.

B) THE FEEDER LIBRARY The Cable Data Feeder Library includes the feeder size, diameter, area (SQIN), weight

per foot of single cable, insulation, material (A = aluminum, C = copper), voltage, area (CMILL) and codeword.

C) THE RACEWAY LIBRARY The Raceway Data Library includes all standard raceway sizes. User can add, modify

and delete the information to suit his or her needs. XI. CABLE REEL BACK PRESSURE The cable reel backpressure is a common value expressing the estimated reel back tensions of

100 lbs.

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XII. METHOD OF CALCULATION The equations used in this program come from standard static and dynamic analysis principles.

The references are: 1: Edison Electric Institute, Underground Systems Reference Book, 1957. 2: Rifenburg, R.C., Pipe Line Design For Pipe-type Feeders, AIEE Transaction on Power

Apparatus and Systems, Vol. 72, part III, December 1953. XIII. TECHNICAL PARAMETERS 1: CABLE DIAMETERS AND WEIGHTS This information is listed in the manufacturers' catalogs (see the program Feeder Library). 2: CONDUIT SIZE The National Electric Code, NEC, specifies the permissible conduit fill and conduit sizes

(see the program Raceway Library). 3: CABLE CLEARANCE It is important to calculate the clearance between cables and conduit to ensure that

cables can be pulled through the conduit, as follows: D = conduit inside diameter in inches; d = ∗ 1.05 × nominal cable outside diameter in inches; C = clearances in inches; ∗ 1.05 Safety factor for manufacturer tolerance. For single conductor cable pull C = D - d (1) For three-conductor cable pull:

C = Dd

- 1.366d + 0.5 ( D - d ) 1 - dD - d

2

⎛⎝⎜

⎞⎠⎟

⎡

⎣⎢⎢

⎤

⎦⎥⎥

(2)

For four-conductor cable pull:

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C = (D- d) - 2 dD- d

2 (3)

4: JAM RATIO When the ratio of the inside diameter of the conduit to the cable diameter is equal to 3,

one of the cables in a 3 or 4 cable pull may slip between two other cables, thus causing the cables to jam in the conduit; this is especially true when the cable is pulled around a bend.

With: D = conduit inside diameter in inches, and d n = nominal cable outside diameter in inches, (4) one of the following statements should be satisfied to avoid cable jam:

1.05Dd

< 2.9n

D1.03d

> 3.1n

5: WEIGHT CORRECTION FACTOR Calculation of weight correction factor is needed for proper distribution of single cables

weight in multiple cable pull. Weight correction factors are: For single cable: Wc = 1 (5) For 3-single cables in triangular configuration:

Wc = 1

1 - dD - d

2⎛⎝⎜

⎞⎠⎟

⎡

⎣⎢⎢

⎤

⎦⎥⎥

(6)

For 3-single cables in cradled configuration:

Wc = 1 + 43

d(D - d)

2⎛⎝⎜

⎞⎠⎟ (7)

For 4-single cables in diamond configuration:

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Wc = 1 + 22

dD - d

⎛⎝⎜

⎞⎠⎟

(8)

Note that: D = inside diameter of conduit in inches; d = nominal outside diameter of a single cable in inches; Wc = weight correction factor, no dimensions. 6: EFFECTIVE COEFFICIENT OF FRICTION The effective coefficient of friction is expressed as the product of the basic coefficient of

friction and the weight correction factor. K0 = basic coefficient of friction Wc = weight correction factor K = effective coefficient of friction K = K0 Wc 7: DYNAMIC COEFFICIENT OF FRICTION The dynamic coefficient of friction is a factor which, when multiplied by the normal force

exerted by the cable on the conduit, yields the pulling tension required to keep the cables in motion. The force exerted by the cable is due to its own weight added up to the weight of all other cables resting on it.

8: SIDEWALL BEARING PRESSURE This is a radial pressure experienced by the cable as it is pulled through a curved section. With Wc = weight correction factor, R = inner radius of conduit bend, T = maximum

tension of cable(s) in pounds, and SWBP = sidewall bearing pressure on cable with greatest radial load:

Ri = (Rc - D)

12

12 (9)

where: Ri = inside radius of bend in feet; Rc = centerline radius of bend in inches;

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D = diameter of duct in inches. For single cable:

SWBP = TR

(10)

For 3-cable cradled formation:

SWBP = (3Wc - 2)T3R

(11)

For 3-cable triangular formation:

SWBP = WcT2 R

(12)

For 4-cable in diamond formation:

SWBP = (Wc - 1)TR

(13)

Cable Sections

Figure 5

STRAIGHT OR HORIZONTAL PULL

T2 = T1 + WKL (14)

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L = actual length of the section of cable in feet K = effective coefficient of friction W = total weight of cable in conduit in pounds/foot T1 = the tension at the beginning of pull in pounds

T2 = the tension at the end of pull in pounds

Figure 6

HORIZONTAL BEND

T2 = T Cosh(K FSin h(K1 θ θ) )+

F = T (WR)12 2+

θ = bend angle from horizontal

R = inside radius of conduit bend

Figure 7

SLOPE UP PULL

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T2 = T1 + LWX (15) X = SIN K COSθ θ+ (16) θ measured from horizontal axis

Figure 8

SLOPE DOWN PULL

T2 = T1 - LWY (17) Y = SIN K COSθ θ− (18) θ measured from horizontal axis

Note: An upward or downward sloping segment with a specified arc angle of 90 degrees can be used to model a vertical pull.

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Figure 9

VERTICAL DIP

In vertical dip with D1 small compared to L (Length of section) T = 1

K KT e + RW(e - 1)θ θ (19) where

θ = 4 D’L

and R =

L2

4 D’

2⎛⎝⎜

⎞⎠⎟

(20)

Use coefficient of friction μ f for SWBP p 150 lbs/ft For T ≤ RW T2 = T1 + WKL (21) For T ≥ RW T2 = 1

4 K 4 K 3K KT e + RW[e - 2 e + 2 e - 1]θ θ θ θ (22) D' = Depth of Dip from horizontal axis

S = 12

length of the Dip Section

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Figure 10

CONVEX DOWNWARD BEND

θ measured from vertical axis

T2 = 1K

2T e + WR1+ k

Zθ (23)

Z = 2 1KSIN K e COS2

Kθ θθ− − −( ) ( ) (24)

Figure 10A

θ = offset angle from vertical axis θ measured from vertical axis by angle θ

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Ta = 1K

2 1T e + WR1+ K

Zaθ (25)

Z1 = 2 K SIN - (1- K )(e - COS )a

2 Kbaθ θθ (26)

Tb = 1K

2 2T e + WR1+ K

Zbθ (27)

Z2 = 2 K SIN - (1- K )(e - COS )b

2 Kbbθ θθ (28)

θ = θ θb a− (29) θ b = total angle from vertical axis and T2 = T T Tb a 1− + (30)

Figure 11

CONVEX UPWARD BEND

θ measured from vertical axis

T2 = 1K

2 1T e + WR1+ K

Yθ (31)

Y1 = 2 K e SIN + (1 - K )(1 - e COS )K 2 Kθ θθ θ (32)

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Figure 11A

θ measured from vertical axis by θ a

T2 = b 2 2

K

T - WR1+ K

Y

e aθ (33)

Y2 = 2 K e SIN + (1 - K )(1 - e COS )K

a2 K

aa aθ θθ θ (34)

Tb = 1K

2 3T e + WR1 + K

Ybθ (35)

Y3 = 2 K e SIN + (1 - K )(1 - e COS )K

b2 K

bb bθ θθ θ (36) θ = θ θb a− (37)

Figure 12

CONCAVE UPWARD BEND

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θ measured from vertical axis

T2 = 1K

2T e - WR1+ K

Zθ (38)

Z = 2 K SIN - (1- K )(e - COS )2 Kθ θθ (39)

Figure 12A

θ measured from vertical axis by angle θ a

Ta = 1K

2 1T e - WR1+ K

Zaθ (40)

Z1 = 2 K SIN - (1 - K )(e - COS )a

2 Kaaθ θθ (41)

Tb = 1K

2 2T e - WR1+ K

Zbθ (42)

Z2 = 2 K SIN - (1- K )(e - COS )b

2 Kbbθ θθ (43)

where θ = θ θb a− (44) and T2 = T T Tb a 1− + (45)

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Figure 13

CONCAVE DOWNWARD BEND

θ measured from vertical axis

T2 = 1K

2 1T e - WR1+ K

Yθ (46)

Y1 = 2 K e SIN + (1 - K )(1 - e COS )K 2 Kθ θθ θ (47)

Figure 13A

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θ measured from vertical axis by angle θ a

T2 = b 2 2

K

T + WR1 + K

Y

e aΘ (48)

Y2 = 2 K e SIN + (1 - K )(1 - e COS )K

a2 K

aa aθ θθ θ (49)

Tb = 1K

2 3T e - WR1 + K

Ybθ (50)

Y3 = 2 K e SIN + (1 - K )(1 - e COS )K

b2 K

bb bθ θθ θ (51) θ = θ θb a− (52)

Figure 14

Note that arcs and offsets are always measured from vertical. XIV. PROGRAM FEATURES - The program helps you in quickly and easily performing "What if" type of analysis by

permitting you to design and view raceway configurations while testing different lubricating compounds.

- Provides graphic display of raceway sections in front, side, top and perspective views.

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- Converts all quantities from U.S. Customary to SI units at the touch of a button. - Provides both graphic and text output. - Provides quick access help to virtually every item displayed on a screen. - Maintains libraries of standard and user defined cable parameters, raceways and

lubricating compounds for quick inclusion into analysis. - Performs both forward and reverse pull analyses in a single pass. 14.1 USING THE PROGRAM'S BUILT-IN HELP FACILITY

“Help” menu consists of Contents, Using Help, and About….

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14.2 MAIN MENU ITEMS

Files This entry will get you into the program's job file manager. Submenu entries can

be used to create new files, load existing ones, edit or delete program job data files.

Edit Edit the current job file. If no job is currently loaded, the program will

automatically generate a list from which to choose. Analyze Run an analysis. If you have yet to load a job file, you will be asked to choose

from a directory listing. This must be done prior to running any analysis. Tools This entry will get you into the program's general editors. Once there, you can

edit any of the program reference library data files. Help Enter the system online help facility.

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14.3 PROGRAM SUBMENU ENTRIES

New This entry will get you into the program's job data editor. It can be used to create

a new job data file for analysis. Open… Load an existing job file for editing, viewing, or running an analysis. Close Close the job file. Save Save the file under the same name. Save As… Save the file under a different name. Print Print the results to a printer. Print Setup… Setup the document print characteristics. Exit Exit from the program User Tip: If you want to perform an analysis on a brand new project, whose characteristics

are similar to an existing job, simply call up the old job via the "Files/Load

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Existing" menu entry. Edit the old job parameters to match the new project's parameters and save the file to a new job filename.

Cable Library Access the cable parameters library editor. Compound Library Access the cable lubricating compounds library editor. Raceway Library Access the cable raceway library editor.

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XV. REFERENCES 1: Buller, F. H., "Pulling Tension During Cable Installations in Ducts or Pipes", General

Electrical Review, Schenectady, NY, Vol. 52, No. 8, pp. 21 - 23, August 1949. 2: Mehta, Yash, "Design and Installation of Large Feeders", Electrical Systems Design, pp.

32 - 36, June 1987. 3: Rifenburg, R. C., "Pipe-Line Design for Pipe-Type Feeders", AIEE Transactions on

Power Apparatus and Systems, Vol. 72, Part III, pp. 1275 - 1288, December 1953. 4: Vartanian, Sookie, Sandler, Arthur N., "Cable Pulling Design for Practical Applications in

Modern Refineries", IEEE Transactions on Industry Applications, Vol IA-10, No. 3, May/June 1974.

XVI. GLOSSARY OF TERMS AND DEFINITIONS 1. Cable Area Enter the cable area, 0.001 - 99.999. 2. Cable Code Word Use up to 16 characters to uniquely describe or label the entry. 3. Cable Configuration Use either one of the +/- keys, or the <F2> key, to select the cable

configuration (e.g. single, triangular, etc.). 4. Cable Diameter Enter the cable diameter, 0.001 - 99.999. 5. Cable Insulation Enter up to 4 characters to describe the type insulation used in the

cable (e.g. "XPC"). 6. Cable Material Use either one of the +/- keys, or the <F2> key, to select the material

used in the core of the cable. (e.g. copper, aluminum). 7. Cable Size Enter up to 4 characters to describe the cable size (e.g. "1/0"). 8. Cable Weight Enter the cable weight per unit length, 0.001 - 99.999. 9. Coefficient of Friction Enter the coefficients of friction for the compound corresponding to

low and high sidewall bearing pressure, 0.001 - 99.999. 10. Compound Description Use up to 20 characters to describe or label the entry. 11. Job Description This field provides you with an area to describe the analysis or note

important characteristics of the analysis. (Optional, but recommended).

12. Maximum Allowed SWP Enter the maximum allowed side wall bearing pressure, 0 - 9999. 13. Maximum Allowed Tension Enter the maximum allowed tension, 0 - 9999. 14. Nominal Raceway Size Enter the nominal size of the raceway, 0.001 - 99.999. 15. Output File Choices You may send the analysis results to a file, or an attached printer, or

you may cancel, and return to the view screen. Simply use the "+" and "-" keys to change the entry in the box until the

entry matches your desired action. Then depress the <ENTER> key to signify your choices.

16. Phi In the perspective view, the angle of rotation about the x-axis.

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17. Pull Direction Specify the direction of the pull you wish displayed (e.g. forward,

reverse). This choice effects the information displayed when a section is chosen for detail information and for section highlighting of cable breaks.

18. Raceway Diameter Enter the actual diameter of the raceway, 0.001 - 99.999. 19. Reel Back Tension Enter the reel back tension, 0 - 9999.9 20. Section Arc The angle subtended by bend for curved sections or angle of slope

measured from horizontal for sloped sections. Enter the angle in degrees of the section element for sections of horizontal bend, concave bend up, concave bend down, convex bend up, convex bend down, slope up, and slope down types. Range: 0 - 90 (-180 - +180 for horizontal bend).

21. Section Length Enter the length of the section, 0.001 - 9999.999. 22. Section Offset Enter the angle in degrees of the offset from vertical in a clockwise

direction of the section element for sections of concave bend up, concave bend down, convex bend up, convex bend down, slope up, and slope down types 0 to 90 degrees.

23. Section Radius Enter the radius of the section for sections of horizontal bend,

concave bend up, concave bend down, convex bend up, convex bend down, and vertical dip types 0.001 - 9999.999.

24. Section Type Use either one of the +/- keys, or the <F2> key, to select the section

type (e.g. horizontal pull, vertical dip, etc.). 25. System This field requires you to choose the measurement system (Metric,

U.S. Customary) you wish the program to use during data input and output.

Note: All calculations performed internally are in the metric system.

U.S. Customary measurements will be automatically converted prior to display.

26. Theta In the perspective view, the angle of rotation about the y-axis. 27. View Use either one of the +/- keys, or the <F2> key, to select the viewing

angle (e.g. front, top, side, perspective) of the raceway path display. Note that by choosing the perspective you can specify the viewing angles.

28. Voltage Enter the voltage, 0 - 99999.

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XVII. ADDITIONAL NOTES Limitations/Caveats Program Limitations: Item Maximum - Sections/Job 100 - Cables types in library 100 - Raceway sizes in library 100 - Lubricating compounds in library 100 Abbreviations Used: Metric U.S. Customary Mass kg - Kilogram = 2.205 lb - pound mass Length m - meter = 3.281 ft - feet cm - centimeter = 0.394 in - inches Area sq cm - square cm = 0.155 sq in - square inch Force N - Newton = 0.225 lb - pound force Pressure kPa - 1000 Pascals = 0.145 psi - pounds/sq in Files Used: File Description ------------ ----------------------- * cpl Cable pull project file cablpull hlp Help file cables cbl Cable type library file compound cml Lubricating compound library file raceways rwl Raceway library file

Cable Pulling

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APPENDIX A: Cable Pulling Tutorial A Cable pulling is a critical operation that involves more than just applying lubrication and sheer force. Cables are the interconnecting media between the different elements of the power system. The likelihood of a cable failure turns into an unfortunate reality when they have sustained damage during installation.

To ensure that the cable pulling operation does not damage the conductors, one must first evaluate the type and geometric configuration of the raceway. This will determine how the cables will be affected.

Some of the issues to keep in mind are:

a. Cable Geometric Configuration: Section IV of this manual illustrates that, depending on their number, the cables will occupy the

raceway in unique physical configurations. These configurations are referred to as Single Cable, Three Cables Triangular, Three Cables Cradled, and Four Cables Diamond. Refer to Figures 1, 2, 3 and 4 in Section IV of this manual.

Cable configuration plays an important role in the integrity of the cable pull; because it has a direct

effect on how much frictional force (drag) is placed on the cables during installation. In order to determine the actual configuration that the cables will adopt, the ratio of the inside

diameter of the raceway (D) to the outside diameter of an individual cable (d) is used - D/d ratio. When pulling three individual conductors from three separate reels, the following guidelines can be followed to determine the type of configuration:

D/d < 2.5: The cables will lay in a Triangular Configuration 2.5 < D/d < 3.0: The cables may lay in a Triangular or Cradled Configuration D/d > 3.0: Cables will lay flat The diamond configuration occurs when pulling four individual conductors with D/d < 3. When pulling

triplexed or quadruplexed single-conductor as assemblies from one reel, the configurations will always be triangular for triplexed and diamond for quadruplexed.

b. Cable Weight Correction:

When installing two or more single conductor cables in a raceway, the sum of the forces exerted between the cables and the raceway is greater than the sum of the individual cable weights. To properly account for this increased effective weight of the cables, a correction factor must be applied. This factor will help to evaluate the actual pulling tension more accurately. For instance, a cradled configuration with a 40% raceway fill will yield a weight correction factor of 1.441, in contrast to the triangular case, which has a value of 1.222.

Unless the cable being pulled is configured as triplexed single conductors, it should be assumed that one is dealing with a cradled configuration. This will result in a more conservative design.

c. Sidewall Bearing Pressure:

As a cable is pulled through a bend in the raceway system, pressure builds up between the cable and the bend. The term that is used to describe this pressure is sidewall-bearing pressure (SWBP). This phenomenon has dramatic effects on the design parameters of the power distribution feeder, because it directly relates to bending radius, pulling tension, and cable weight.

Cable Pulling

A-2

The SWBP is a function of the tension out of the bend (in lbs.) and the bend radius (in ft). The SWBP is a unit of force per unit length. Table A shows the SWBP equations as they apply to the different types of configurations. Table B lists some of the maximum recommended SWBP for different types of cables.

Table A: SWBP Equations

Number of cables Configuration SWBP equation 1 Single SWBP=T÷R (eq.5.) 3 Cradled SWBP=[(3W-2) x2T]÷3R(eq.6) 3 Triangular SWBP=WT÷2R (eq.7) 4 Diamond SWPB=[(W-1) x2T] ÷R (eq.8)

W = Weight correction factor T = Calculated tension R = Radius of bend (inside radius)

Note: For multi conductor cables, the single conductor equation should be used.

Table B: Recommended Maximum Sidewall Bearing Pressures

Cable Maximum Construction type SWBP (lbs./ft) 1 XLPE Insulation/Jacket-600V 1200 EPR, Neoprene-600V cable 1000 PE & XLPE insulation concentric wire shield: Without jacket 1200 2 With encapsulating jacket 2000 PE and XLPE insulation, LC shield LDPE jacket 1500 PE, XLPE, EPR insulation, Concentric wire or tape shield, LDPE and PVC sleeved jackets. 2000 3

Lead sheathed cable, with and without jackets: XLPE insulation 2000 EPR insulation 2000

XLPE insulation, copper ribbon Shield, MDPE sleeved jacket 2000

Note 1 When considering the use of the above limits, the tension on the cable conductor

should not exceed 10,000 psi for annealed stranded copper and 6000 psi for half and full hard stranded aluminum. For three single-conductor cables in parallel configuration, the allowable conductor stress should be based on two cables sharing the tension.

Note 2 For pull of three single-conductor cables in parallel, a maximum SWBP of 750 lbs./ft is recommended.

Note 3 The recommended SWBP limit should be reduced to 1500 lbs./ft when the jacket is not applied tightly to the cable core.

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d. Cable Jamming: Jamming occurs as three or more cables lying side-by-side are pulled in a single plane. As the cables are pulled through a bend the curvature will squeeze the cables, causing them to jam and consequently damage the insulation. Typically, the risk of jamming cables is not high when pulling one or two single conductors, or a single multi-conductor cable with an overall jacket. The risk is also negligible when dealing with multi-conductor cables made up of triplexed or quadruplexed single conductors. To determine the potential for a jamming problem to exist, the ratio of the raceway inside diameter (D) to the individual conductor's outside diameter (d) can be used once again. Keep in mind that bends have oval cross sections; therefore the diameter measurement must be increased by 5%. Following are some guidelines for evaluating the potential presence of a jamming problem: • If 1.05 times D/d is less than 2.5, jamming is not possible. • If 1.05 times D/d is less than 3.0 but greater than 2.8, jamming is very probable. • If 1.05 times D/d is greater than 3.0, jamming is not possible.

Another special note: Avoid jam ratios of 2.8 to 3.2 for extruded dielectric cables.

The following exercise will illustrate how the cable pulling analysis can be conducted using EDSA's "Cable Pulling and Sidewall Pressures" program. The case study is based on the EPRI "Maximum Safe Pulling Lengths for Solid Dielectric Insulated Cables" in Section 5 of Volume 2: Cable User's Guide. EPRI EL-3333-CCM, Volume 2 - Research Project 1519-1.

F.I.

1

234567891011

Profile View

Plan View

Figure A-1 Tutorial Example - File: epri.cpd (not to scale)

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The following table describes each of the sections shown in Figure A-1. The order of the sections indicates the forward pulling direction:

Length Arc Deg Off Radius Sec Description (ft) (Deg) Vertical (ft)

Comments

F.I. Concave bend down 10.0 90.0 0.0 6.0 Feed-in section 1 Horizontal pull 80.0 0.0 0.0 0.0 2 Horizontal bend 25.0 90.0 0.0 12.5 3 Vertical dip 110.0 0.0 0.0 3.0 4 Horizontal pull 30.0 0.0 0.0 0.0 5 Convex bend down 7.0 45.0 0.0 6.5 6 Slope down 15.0 45.0 0.0 0.0 7 Concave bend down 7.0 45.0 0.0 6.5 8 Concave bend up 7.0 45.0 0.0 6.5 9 Slope up 30.0 45.0 0.0 0.0 10 Convex bend up 7.0 45.0 0.0 6.5 11 Horizontal pull 55.0 0.0 0.0 0.0

The cable data are as follows: Type of pull: 3 cables in duct Cable Description: 1000 kcmil 15kV shielded aluminum conductor. Insulation: XLPE; PE jacket Cable Diameter: 1.86 inches Conductor area: 0.7854 inches2 Weight of 3 cables: 5.05 LB/ft. Diameter of Conduit: 6.065 inches Conduit Material: PVC Type of Lubricant: Soap and Water Low SWBP: 0.45 High SWBP: 0.20 Reel back tension: 100 lbs. Before using EDSA's Cable Pulling program the user must keep in mind the following guidelines: 1. There must be a minimum of two sections of cable, the first of which must be defined as the portion

that pushes or pulls the cable. 2. There must be an eye on the initial section for anchoring the pulling operation. In other words, it is

important for the user to note that the program reserves the first segment to model the characteristics of the cable feeder. An example of this would be to specify a concave bend down section of radius 4 ft. with a 90-degree arc to model a cable coming off a large spool. This section is always referred to as the "feeder" or "feed-in" section in the output. Although the feeder section is not explicitly listed in the forward or reverse pull output tables, careful inspection of the data shows that resulting tension is present in both tables and that the feeder section is always the first section whether in a forward or reverse pull. Although this may initially seem counter intuitive, once you remember that the feeder section is modeling the tension due to the source of the physical cable (in most cases a spool), it becomes obvious that the feeder section is the first section in both a forward and reverse pull situation.

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Step 1. From the main EDSA menu, select “Analysis/Additional Calculations/Cable Pulling”.

Step 2. Once in the “Cable Pull” program main interface, proceed to create a new job file by selecting “File/New”.

Step 3. Proceed to name the new file and select “Save”. In this example, the file will be designated as “EPRI.cdp”.

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Step 4. Select “Edit / Edit Job File”.

Step 5. Proceed to enter the data for the cable under study, as required by the dialog box shown here. In this example, all the information has been manually entered based on the data provided at the beginning of this tutorial. Select “Save” to continue.

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This screen capture illustrates how to use data from the existing libraries, by selecting their respective pick-lists.

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Length Arc Deg Off Radius Sec Description (ft) (Deg) Vertical (ft)

Comments

F.I. Concave bend down 10.0 90.0 0.0 6.0 Feed-in section 1 Horizontal pull 80.0 0.0 0.0 0.0 2 Horizontal bend 25.0 90.0 0.0 12.5 3 Vertical dip 110.0 0.0 0.0 3.0 4 Horizontal pull 30.0 0.0 0.0 0.0 5 Convex bend down 7.0 45.0 0.0 6.5 6 Slope down 15.0 45.0 0.0 0.0 7 Concave bend down 7.0 45.0 0.0 6.5 8 Concave bend up 7.0 45.0 0.0 6.5 9 Slope up 30.0 45.0 0.0 0.0 10 Convex bend up 7.0 45.0 0.0 6.5 11 Horizontal pull 55.0 0.0 0.0 0.0

Step 6. The next step is to add each section of the cable run. To initiate the process, select “Edit / Edit Section”.

Step 7. This dialog box is where all the different sections of the cable-pull exercise will be entered and characterized according to the example described at the beginning of this tutorial. For the convenience of the reader, the table below describes the sections that will be modeled.

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Step 8. To add the first section (“Feed in” section), select the “Add” command.

Step 9. From the “Selection Type” pick-list select “Concave bend down”. For clarity and convenience, the program will automatically display a graphical representation of the geometrical characteristic of each section.

Step 10. Enter the physical dimensions of the section, and select “OK”.

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Step 12. Using the same guidelines illustrated in steps 8 to 11, proceed to enter the remaining 11 sections of the cable pull. The final product will look like this. When finished, press “OK” to continue.

Step 11. The first section is automatically labeled as “Feed in”, and added to the list as shown here. To edit any existing sections, simply select it from the list and press “Edit”. Double-clicking also works for this purpose. Similarly, to delete any sections of the cable pull, select the section to be deleted and press “Delete”.

The following pages will show the editor for sections 1 to 11.

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Section 1

Section 2

Section 3

Section 4

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Section 5

Section 6

Section 7

Section 8

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Section 9

Section 10

Section 11

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Step 13. Proceed to save the file by selecting “File / Save”.

Step 14. To view a graphical representation of the cable run, select “Analyze / View”.

Step 15. The figure shows the “Forward Pull” “Side View” of the cable run. The commands on the right of the figure will be explained in the next pages.

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The output report can also be generated as described in step 16 of this tutorial.

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This graph was generated as follows: 1. Select “Perspective View”. 2. Theta = 90 Deg. (rotation about Y axis) 3. Phi = 5 Deg. (rotation about X axis 4. Select “Refresh”.

Select the “Direction” of the pull (Forward or Reverse) and then select the desired view angle. For “Perspective”, select the “Theta” and “Phi” angles and then press “Refresh”. Select “Close” to return to the main menu.

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Step 16. To run the analysis and generate the output report, select “Analyze / Generate output for Cable Pull”.

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The Complete report follows: EDSA Cable Pulling, Version 4.10.00 Project No. : Page : 1 Project Name : Date : Project Title : Time : Drawing No. : Company : Revision No. : Engineer : Job File Name : EPRI Checked By : Scenario : Checked Date: ------------------------------------------------------------------------ System: English Cable Configuration Cradled (3) Reel back tension on cables 100.0 lb Pulling Compound SOAP Basic coefficient of friction Low Sidewall bearing pressure 0.450 High Sidewall bearing pressure 0.200 Design maximum allowed tension 4000 lb Design maximum allowed SWP 400 lb/ft Raceway Data: Size 6.000 in Inner diameter of duct 6.065 in Area 28.89 sq in Percent fill 28.22 Cable Data: Library Name : Edsa Standard Size 1000 Type Aluminum Insulation XLP Voltage 15000 Diameter of single cable 1.860 in Area 0.785 sq in Weight 1.683 lb/ft Total area 2.356 sq in Total weight 5.050 lb/ft General Information: Cable clearance in conduit with no tolerance 2.606 in with 5% tolerance 2.247 in Jam ratio with 3% tolerance on cable 3.166 with 5% tolerance on conduit 3.424 Feed-in Conduit Description Concave bend down Length 10.0 ft Radius 6.0 ft Tension 164.9 lb Sidewall Bearing Presure 16.3 lb/ft Arc 90.0 Angle off vertical axis 0.0 Forward Pull Length Arc Deg Off Radius Actual Tension SWP Sec Description (ft) (Deg) Vertical (ft) (ft) (lb) (lb/ft) 1 Horizontal pull 80.0 0.0 0.0 0.0 90.0 394 0.0 2 Horizontal bend 25.0 90.0 0.0 12.5 115.0 966 45.9 3 Vertical dip 110.0 0.0 0.0 3.0 225.0 1281 0.0 4 Horizontal pull 30.0 0.0 0.0 0.0 255.0 1367 0.0 5 Convex bend down 7.0 45.0 0.0 6.5 262.0 1663 152.0 6 Slop down 15.0 45.0 0.0 0.0 277.0 1640 0.0 7 Concave bend down 7.0 45.0 0.0 6.5 284.0 1981 181.1 8 Concave bend up 7.0 45.0 0.0 6.5 291.0 2419 221.1

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9 Slop up 30.0 45.0 0.0 0.0 321.0 2587 0.0 10 Convex bend up 7.0 45.0 0.0 6.5 328.0 3171 289.9 11 Horizontal pull 55.0 0.0 0.0 0.0 383.0 3329 0.0 All tension distributed on 2 cables 1664 lb/Conductor 2119 psi All tension distributed on 3 cables 1110 lb/Conductor 1413 psi Reverse Pull Length Arc Deg Off Radius Actual Tension SWP Sec Description (ft) (Deg) Vertical (ft) (ft) (lb) (lb/ft) 11 Horizontal pull 55.0 0.0 0.0 0.0 65.0 322 0.0 10 Convex bend down 7.0 45.0 0.0 6.5 72.0 509 46.5 9 Slop down 30.0 45.0 0.0 0.0 102.0 463 0.0 8 Concave bend down 7.0 45.0 0.0 6.5 109.0 693 63.4 7 Concave bend up 7.0 45.0 0.0 6.5 116.0 1077 98.4 6 Slop up 15.0 45.0 0.0 0.0 131.0 1161 0.0 5 Convex bend up 7.0 45.0 0.0 6.5 138.0 1842 168.4 4 Horizontal pull 30.0 0.0 0.0 0.0 168.0 1928 0.0 3 Vertical dip 110.0 0.0 0.0 3.0 278.0 2470 5.8 2 Horizontal bend 25.0 90.0 0.0 12.5 303.0 3671 174.5 1 Horizontal pull 80.0 0.0 0.0 0.0 383.0 3900 0.0 All tension distributed on 2 cables 1950 lb/Conductor 2483 psi All tension distributed on 3 cables 1300 lb/Conductor 1655 psi

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Step 17. To edit the program’s Cable, Compound and Raceway databases, refer to the “Tools” menu and select the desired library. Step 18.

Each library can have its existing components deleted or modified, and new components added. Simply use the “Edit”, “Add” and “Delete” commands as shown.

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Enter the new cable name and data; click OK.

After the library is closed and reopened, the new cable and its properties have been added to the library.