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IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

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IEEE Recommended Practice for
Cable Installation in Generating
Stations and Industrial Facilities

Keywords: IEEE Power and Energy Society,IEEE Std 1185™-2019 (Revision of IEEE Std 1185-2010)

IEEE Recommended Practice for STANDARDS
Cable Installation in Generating
Stations and Industrial Facilities

IEEE Power and Energy Society

Developed by the
Insulated Conductors Committee
IEEE Std 1185™-2019

(Revision of IEEE Std 1185-2010)

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IEEE Std 1185™-2019

(Revision of IEEE Std 1185-2010)

IEEE Recommended Practice for
Cable Installation in Generating
Stations and Industrial Facilities

Developed by the
Insulated Conductors Committee
of the
IEEE Power and Energy Society
Approved 7 November 2019
IEEE SA Standards Board

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Abstract: Guidance for the proper installation of cable in generating stations and industrial facilities
is provided in this recommended practice.

Keywords: American wire gauge, AWG, basket grip, bend radius, cable, cable cleats, cable
jamming, cable testing, cable ties, cable tray, cmil, conduit, duct bank, ducts, English units, figure 8,
galloping, IEEE 1185™, installation, jam ratio, kcmil, luff, metric units, OD, outside diameter, overall
diameter, pull back, pull tension, pullby, pulling bend radius, ropes, sidewall bearing pressure,
sidewall pressure, slack puller, sleeve, swivel, training bend radius, trench, wire, wire way

The Institute of Electrical and Electronics Engineers, Inc.
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Copyright © 2020 by The Institute of Electrical and Electronics Engineers, Inc.
All rights reserved. Published 15 May 2020. Printed in the United States of America.

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Incorporated.

National Electrical Code, NEC, NFPA 70 are registered trademarks of the National Fire Protection Association, Inc.

National Electrical Safety Code and NESC are both registered trademarks and service marks of the Institute of Electrical and Electronics
Engineers, Inc.

PDF: ISBN 978-1-5044-6280-8 STD23961
Print: ISBN 978-1-5044-6281-5 STDPD23961

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Participants

At the time this IEEE recommended practice was completed, the D5W Station Cable Insulation Working
Group had the following membership:

John E. Merando Jr., Chair
William G. Bloethe, Vice Chair

Keith Bagwell Ajit K. Gwal David Needham
John R. Barker Charles W. Hills James S. Parham
Ettore J. Bartolucci Raihan K. Khondker Jan S. Pirrong
Michael G. Bayer Robert Konnik Eric J. Rasmussen
Kent W. Brown Benjamin Lanz David Rouison
James Conrad Philip T. Laudicina Fanta Sacko
Lawrence Cunningham Michael K. Lauxman Robert Schmidt
Charles A. Darnell Elliot B. Lee Albert Spear
Doug DePriest Gerald Liskom Herbert W. Stansberry
Arturo Maldonado Gabriel J. Taylor
(Deceased) Andrew J. Mantey Wayne E. Walters
Tim Fallesen Nader Moubed Robert F. Wobick
Robert E. Fleming Ross A. Murphy Chris Wright
Steven Graham

The following members of the individual Standards Association balloting group voted on this recommended
practice. Balloters may have voted for approval, disapproval, or abstention.

Saleman Alibhay Ernest Duckworth William Lockley
Keith Bagwell Donald Dunn Lawrenc Long
John Barker Tim Fallesen Daniel Mainstruck
Thomas Barnes Leonard Fiﬁeld Arturo Maldonado
Ettore Bartolucci Rostyslaw Fostiak Reginaldo Maniego
Earle Bascom III Carl Fredericks Andrew Mantey
Manfred Bawart Craig Goodwin William McBride
Michael Bayer Steven Graham William McDermid
W. J. (Bill) Bergman Randall Groves John E. Merando Jr.
Thomas Blair Lee Herron James Michalec
William G. Bloethe Lauri Hiivala Daleep Mohla
Kenneth Bow Charles Hills Rachel Mosier
Derek Brown Ajit Hiranandani Nader Moubed
Kent Brown Werner Hoelzl Ross Murphy
Gustavo Brunello Robert Hoerauf Michael Nadeau
Demetrio Bucaneg Jr. Richard Jackson Arthur Neubauer
Nissen Burstein Laszlo Kadar Michael Newman
William Byrd John Kay Joe Nims
Thomas Campbell Yuri Khersonsky Lorraine Padden
Robert Carruth Delavar Khomarlou James Parello
Suresh Channarasappa Boris Kogan James Parham
Arvind Chaudhary Robert Konnik Howard Penrose
William Chen Thomas Koshy Christopher Petrola
Michael Chirico Edwin Kramer Jan S. Pirrong
Robert Christman Jim Kulchisky Percy Pool
Randy Clelland Mikhail Lagoda Craig Preuss
James Conrad Chung-Yiu Lam Iulian Proﬁr
Lawrence Cunningham Benjamin Lanz Eric Rasmussen
Charles Darnell Philip Laudicina Lakshman Raut
Glenn Davis Michael Lauxman Gary Savage
Gary Donner Elliot Lee Bartien Sayogo
Michael Dood Gerald Liskom Robert Schmidt

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Devki Sharma David Tepen Jane Verner
Gilad Shoshani Wayne Timm Wayne Walters
Jerry Smith Peter Tirinzoni Keith Waters
Gary Smullin Nijam Uddin Jared Weitzel
Albert Spear James Van De Ligt Lee Welch
Gregory Steinman Gerald Vaughn Kenneth White
John Stevens John Vergis Robert Wobick
Gary Stoedter Iain Wright

When the IEEE SA Standards Board approved this recommended practice on 7 November 2019, it had the
following membership:

Gary Hoffman, Chair
Ted Burse, Vice Chair
Jean-Philippe Faure, Past Chair
Konstantinos Karachalios, Secretary

Masayuki Ariyoshi David J. Law Annette Reilly
Stephen D. Dukes Joseph Levy Dorothy Stanley
J. Travis Griffith Howard Li Sha Wei
Guido Hiertz Xiaohui Liu Phil Wennblom
Christel Hunter Kevin Lu Philip Winston
Joseph L. Koepfinger* Daleep Mohla Howard Wolfman
Thomas Koshy Andrew Myles Feng Wu
John D. Kulick Jingyi Zhou

*Member Emeritus

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Introduction

This introduction is not part of IEEE Std 1185-2019, IEEE Recommended Practice for Cable Installation in Generating
Stations and Industrial Facilities.

Construction of generating stations and industrial facilities involve the installation of a large number of
cables in various raceway types such as conduits, trays, duct banks, trenches, wire ways, direct burial, etc.
Cable failures can lead to power outages and equipment downtime, resulting in inconvenience at best, lost
production, or worse, a safety issue. This document provides information to help engineers, technicians, and
trades/crafts people avoid potential wire or cable damage during installation, testing, and modification of cable
systems at generating stations and industrial facilities. The majority of these cables are unshielded, and except
in duct banks or direct burial, where water may be present, there is usually no uniform continuous ground
plane on the outside of the cable to allow effective post-installation voltage testing of the cable. Without a
continuous ground plane, effective cable post-installation testing, as well as the ability to detect cable damage
prior to placing the cable in service, is limited. Therefore, greater emphasis needs to be placed on wire and
cable installation methods and practices to assure proper cable installation and long life.

It should be noted that other documents such as cable manufacturer’s cable installation manuals, IEEE/IEC/
AEIC standards, National Electrical Code® (NEC®) (NFPA 70), Canadian Electrical Code (CEC) Parts I, II,
and III, or other local codes, are available that provide cable system design and installation information. It is
not the intent of this recommended practice to replace or supersede the other information but to compliment it
and, as needed, provide more detail, or alternate methods and techniques for proper cable installation. It is also
not the intent of this document to override the installation requirements outlined in governing documents such
as NEC, CEC, cable manufacturer’s installation manuals or permitting documents, etc. Even though utilities
in certain situations may be exempt from requirements of NEC, the utility is not exempt from following good
cable installation practices in an effort to help maximize cable life and help minimize in-service cable failures.

This revision is a complete rewrite to re-organize the information into a more logical sequence. An attempt has
been made to not delete any technical data from the previous edition.

Selected sections have been combined into a comprehensive section (8.2, Securing cable to raceway) that
classifies the forces acting on cables, addresses cable design considerations, and provides in-depth information
on cable supports and restraints, including a discussion on thermal expansion, a list of cable restraint devices
and new calculations. While prior revisions were primarily based on securing vertical cables, this revision
greatly expands on protecting cables from the electrodynamic forces that occur during short circuits.

Improved installation methods are also expected to increase confidence in the ability of the installed cable to
function in the accident environments for nuclear power generating stations, and increase confidence in cables
that improve safety and reliable operation of industrial facilities and cogeneration/fossil plants.

Monitoring pulling tensions is an effective approach to ensuring that the cable pulling limits, such as minimum
bend radius, sidewall bearing pressure (SWBP), and conductor strength, is not exceeded. Since most cable
pulls are manual pulls and the setup time to monitor pulling tension is significant, pulling tensions are typically
only quantitatively monitored when performing long, high tension pulls requiring the use of motorized pulling
equipment. When a cable pull into conduit is made manually, the dynamometer reading has to be adjusted after
measuring various angles. Due to the complexity of this process, manual cable pulls are seldom quantitatively
monitored. This document introduces the use of conduit-cable pulling charts and other methods as alternatives
to direct monitoring of the pulling tensions. This document also provides cable lubrication methods, pull
rope selection criteria, pulling attachment methods, and alternative methods to traditional cable pull tension
monitoring, etc.

Cable pullbys (i.e., pulling cables into conduits that already contain cables) are a common practice in the
utility industry and often not thoroughly addressed in either cable manufacturer literature or existing industry

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standards. Some utilities have reported damage to the existing cables in the conduits when executing pullbys.
Measuring the pulling tensions may help but may not prevent cable damage due to pullbys, because the damage
can occur from the pull rope or pulled by cable as the pull rope or cable passes over or under existing cables.
Instead of prohibiting the practice of cable pullbys, the cable installation process should be more carefully
controlled by evaluating the pullby conditions prior to starting the pullby and by placing restrictions on the
process to avoid cable damage. However, it should be recognized that this is a risky procedure, and damaged
cables or questionable conditions can result from cable pullby practices.

AEIC CG5 [B3] compliments this document for long power cable pulls through duct bank systems and
should be considered as additional reference source. Cable installation information can also be found in
IEEE Std 576™-2000 [B67] and may also be consulted as an additional reference source.

Due to the IEEE Policy 9.18 requirement to show metric units as the primary measurement unit, the English
units are shown for convenience in parentheses after the metric units. The user of this document is cautioned
to pay close attention to the units of the equations (metric versus English) and select units accordingly.
Conformance to this standard can be achieved using either metric or English units provided the user is
consistent when selecting and applying the units. The user is strongly cautioned not to mix units as mixing
units can and will result in installation issues. The user is encouraged to select units that are most familiar to
the installers so as to reduce the potential for creating installation problems that could go undetected until wire
and cable failures occur, which is often years after installation. An attempt was made to keep the significant
figures of the metric and English units comparable. However, due the application of rounding principles, the
mathematical conversion from English numbers to metric numbers may not be exact.

Acknowledgments

Figure 1 through Figure 6, the proper and improper handling of cable reels, are reprinted with permission from
Dekoron Wire and Cable Company, LLC.

Figure 10, Payoff reel positioning, and Figure 14, Example of measuring sidewall pressure are reprinted with
permission from RSCC.

Equation (8) through Equation (12) are derived with permission from General Cable Technology Corporation

Figure 13, Cable configuration for three cables in conduit or duct, is reprinted with permission from The
Okonite Company.

Table 8, Pull rope/tape characteristics, and Table 9, Rope and tape fiber selection guide (typical characteristics),
are reprinted with permission from US. Rope and Cable. This material does not have a copyright and was
obtained from Rope and Fiber Selection Guide section from the website of US. Rope and Cable at www.us
-rope- cable. com.

Figure 11, Example measuring bend radius, Figure 15, Swivel, Figure 19, Compression-type pulling eye, and
Figure 20, Wedge-type pulling eye, are reprinted with permission from Anixter, Canada.

Figure 22, Cable cleat, is reprinted with permission from Talon Products LLC.

Figure G.1, Short circuit current waveform, is reprinted with permission from Talon Products LLC.

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Contents

1. Overview �� 14
1.1 Scope �� 14
1.2 Purpose �� 14
1.3 Units of measure �� 14
1.4 Word usage �� 15

2. Normative references �� 15

3. Definitions, acronyms, and abbreviations �� 16
3.1 Definitions �� 16
3.2 Acronyms and abbreviations �� 16

4. Planning the pull �� 17
4.1 Cable storage, handling, and re-reeling �� 17
4.2 Cable cold temperature limits �� 21
4.3 Raceway types and fill recommendations �� 22
4.4 Planning activities �� 25
4.5 Pre-installation activities for duct banks �� 26
4.6 Distance limitations �� 30
4.7 Reel position and reel back tension �� 30
4.8 Bend location �� 31
4.9 Minimum bend radius �� 32
4.10 Maximum allowable pulling tension (MAPT) �� 35
4.11 Expected pulling tension �� 38
4.12 Cable configurations and cable jamming �� 40
4.13 Weight correction factor �� 41
4.14 Maximum allowable sidewall pressure �� 43
4.15 Expected SWBP �� 44

5. Accessories required for the pull �� 44
5.1 Rope and tapes �� 44
5.2 Swivels and sheaves �� 47
5.3 Rollers �� 49
5.4 Pulling eyes �� 50
5.5 Mare's tails �� 51
5.6 Woven mesh pulling grips and basket grips �� 51
5.7 Tension limiting devices �� 52
5.8 Lubrication �� 54

6. Pulling activities �� 57
6.1 Pre-pulling considerations �� 57
6.2 Set-up considerations �� 58
6.3 Installation considerations �� 58
6.4 Pulling �� 59
6.5 Pullbacks �� 60
6.6 Pushbys �� 61
6.7 Pullbys �� 62
6.8 Pulling in the jam ratio �� 64
6.9 Staggered or gang pulls �� 66
6.10 Overfill conditions �� 66
6.11 Figure-eight cable configurations �� 66

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7. Conduit-cable pulling charts �� 67
7.1 General and methodology �� 67
7.2 Cable types and raceway configurations �� 67
7.3 Use of conduit-cable pulling charts �� 68
7.4 Pulling tensions and bend correction factors �� 69

8. Post cable pulling activities �� 70
8.1 Post installation considerations �� 70
8.2 Securing cable to raceway �� 71
8.3 Support and restraint devices �� 77

9. Cable testing �� 79
9.1 General �� 79
9.2 Low voltage power, control, and instrumentation cables �� 80
9.3 Medium voltage power cables �� 81
9.4 Additional diagnostic testing �� 82

Annex A (normative) Conduit-cable pulling charts �� 83
Annex B (informative) Use of conduit-cable pulling chart examples �� 95
Annex C (informative) Conduit-cable pulling chart methodology �� 100
Annex D (informative) Conduit-cable pulling chart bend correction factor �� 104
Annex E (informative) Glossary �� 106
Annex F (informative) Example of a cable pulling calculation �� 109
Annex G (informative) Example of electrodynamic force calculation �� 118
Annex H (informative) Bibliography �� 120

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List of Figures

Figure 1—Lift reel with both flanges �� 18
Figure 2—Lift reel using pallet �� 19
Figure 3—Lift reel under bottom flange �� 19
Figure 4—Do not nail into reel flanges �� 19
Figure 5—Do not stack material on the top of the reel �� 20
Figure 6—Do not lift reels by the top flange �� 20
Figure 7—Wheel setup comparisons �� 28
Figure 8—Duct bank pull setup—Example 1 �� 29
Figure 9—Duct bank pull setup—Example 2 �� 29
Figure 10—Payoff reel positioning �� 31
Figure 11—Example measuring bend radius �� 32
Figure 12—(a) Expected pulling tension around bends for conduit or duct runs containing horizontal
bends (b) concave bend (c) convex bend �� 39
Figure 13—Cable configuration for three cables in conduit or duct �� 41
Figure 14—Example of measuring sidewall pressure �� 43
Figure 15—Swivel �� 47
Figure 16—Conveyor sheave arrangement �� 48
Figure 17—Three-wheeled pulley �� 48
Figure 18—Example of cable tray with cable supported by rollers during pull �� 50
Figure 19—Compression-type pulling eye �� 50
Figure 20—Wedge-type pulling eye �� 51
Figure 21—Cable pusher �� 53
Figure 22—Cable cleat �� 79
Figure B.1—Isometric of conduit-layout—Example #1 �� 95
Figure B.2—Isometric of conduit layout—Example #2 �� 96
Figure B.3—Isometric of conduit layout—Example #3 �� 98
Figure C.1—Conduit layout—chart developmenet �� 100
Figure D.1—Conduit layout―BendCorr factor �� 104
Figure F.1—Example for calculating cable pulling tensions �� 109
Figure G.1—Short circuit current waveform �� 118

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List of Tables

Table 1—Minimum bend radius multipliers for non-shielded or non-armored cable �� 32
Table 2—Minimum bend radius multipliers for shielded or armored cable �� 33
Table 3—Instrumentation and specialty cable minimum bend radius multipliers �� 34
Table 4—Jacket material tensile stress values �� 35
Table 5—Typical maximum allowable pulling tensions using basket-weave grip �� 36
Table 6—Typical maximum values of allowable SWBP �� 37
Table 7—Guidelines for maximum sidewall pressure values for various cable types �� 43
Table 8—Pull rope/tape characteristics �� 45
Table 9—Rope and tape fiber selection gude (typical characteristics) �� 46
Table 10—Development of effective conduit-length—chart comparison �� 68
Table 11—Slope adjustment factor �� 69
Table 12—Category wire termination �� 71
Table 13—Typical cable support distances per NEC, Section 300.19 �� 73
Table A.1—Conduit-cable pulling chart for control cable �� 83
Table A.2—Conduit-cable pulling chart for control cable �� 84
Table A.3—Conduit-cable pulling chart for control cable �� 85
Table A.4—Conduit-cable pulling chart for control cable �� 86
Table A.5—Conduit-cable pulling chart for power cable �� 87
Table A.6—Conduit-cable pulling chart for power cable �� 88
Table A.7—Conduit-cable pulling chart for power cable �� 89
Table A.8—Conduit-cable pulling chart for power cable �� 90
Table A.9—Conduit-cable pulling chart for instrument cable �� 91
Table A.10—Conduit-cable pulling chart for instrument cable �� 92
Table A.11—Conduit-cable pulling chart for instrument cable �� 93
Table A.12—Conduit-cable pulling chart for instrument cable �� 94
Table B.1—Effective conduit length and degrees of bend—Example #1 �� 95
Table B.2—Effective conduit length and degrees of bend—Example #2 �� 97
Table B.3—Effective conduit length and degrees of bend—Example #3 �� 99
Table C.1—Maximum cable mass (weight) in conduit �� 103
Table D.1—BendCorr adjustment factor— K ¢ = 0.5 �� 105
Table D.2—BendCorr adjustment factor— K ¢ = 0.3 �� 105

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IEEE Recommended Practice for
Cable Installation in Generating
Stations and Industrial Facilities

1. Overview

1.1 Scope

This recommended practice provides guidance for wire and cable installation practices in generating stations
and industrial facilities. It covers installation of cable in trays, conduit, duct banks, wire ways, gutters, and
other raceway systems. It covers medium voltage power cable, low voltage power cable, control cable,
instrumentation cable, coax/triax cable, fiber optic cable, data communications cable, and other specialty
cables used in power plant and industrial environments. This document may also be of benefit for the proper
installation of wire and cable systems in commercial, governmental, and public facilities when the same or
similar wire or cable types and raceways are used.

1.2 Purpose

The purpose of this recommended practice is to provide guidance on how to help prevent installation damage,
which is the single greatest cause of wire and cable failures. Cable failures can lead to power outages and
equipment downtime, resulting in inconvenience at best, lost production, or worse, a safety issue. This
document provides information for engineers, technicians, and trades/crafts people to avoid potential wire
or cable damage during installation, testing, and modification of cable systems at generating stations and
industrial facilities.

1.3 Units of measure

The requirement to show metric units first and, if desired, English units second in parentheses after the metric
units is dictated by IEEE Policy 9.18, and has been implemented in this document even though the customary
practice when installing American Wire Gauge (AWG) wire and cable is to use the English units. The user of
this document may choose to use the English units, since cables made to AWG sizes are typically installed
using English units of measure, even though the metric units are shown first and English units second in
parentheses. Conformance to this recommended practice can be achieved using either metric or English units
provided the user is consistent when selecting and applying the units. The user is strongly cautioned not to
mix units as mixing units can and will result in installation issues. The user is encouraged to select units that
are most familiar to the installers so as to reduce the potential for creating installation problems that could go
undetected until wire and cable failures occur, which is often years after installation. It should also be noted
that due to the reversal of the order of metric and English units, an attempt was made to keep the significant

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

figures of the metric and English units comparable. However, due the application of rounding principles, the
mathematical conversion from English to metric and metric to English may not be exact.

The user is also cautioned to recognize the difference between force and mass especially within the English
system of units since term “pound” (lb) has been often misapplied, which can result in errors in the application
of the equations. Attempts have been made within this document to be clear in the terminology to avoid
confusion and misapplication of this concept in both the metric and English units. It should also be noted
that cable manufacturers give cable weights in SI units using “kg/m” whereas in English the information is
provided in terms of “lb/ft”. The metric units are clearly mass per unit length whereas the English units are
more ambiguous. In this context, cable weight in English units (lb/ft) is a weight per unit length. A pound
(force) is equal to pound (mass) on the surface of the Earth, and thus is not multiplied by the gravity constant
“g”. For clarity, equations using cable weight have often been shown as two equations, one for metric and the
other for English. Since the metric equation uses cable weight in terms of mass per unit length, the acceleration
due to gravity constant “g” has been added to the metric equation as applicable, which does not appear in the
English equation.

1.4 Word usage

The word shall indicates mandatory requirements strictly to be followed in order to conform to the standard
and from which no deviation is permitted (shall equals is required to).1, 2

The word should indicates that among several possibilities one is recommended as particularly suitable,
without mentioning or excluding others; or that a certain course of action is preferred but not necessarily
required (should equals is recommended that).

The word may is used to indicate a course of action permissible within the limits of the standard (may equals
is permitted to).

The word can is used for statements of possibility and capability, whether material, physical, or causal (can
equals is able to).

2. Normative references

The following referenced documents are indispensable for the application of this document (i.e., they must
be understood and used, so each referenced document is cited in text and its relationship to this document is
explained). For dated references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments or corrigenda) applies.

IEEE Std 1210™, IEEE Standard Tests for Determining Compatibility of Cable-Pulling Lubricants with Wire
and Cable.,3,4

NFPA 70®, 2017 Edition, National Electrical Code® (NEC®).5

1The use of the word must is deprecated and cannot be used when stating mandatory requirements, must is used only to describe
unavoidable situations.
2The use of will is deprecated and cannot be used when stating mandatory requirements, will is only used in statements of fact.
3IEEE publications are available from The Institute of Electrical and Electronics Engineers (https://s tandards. ieee. org/) .
4The IEEE standards or products referred to in Clause 2 are trademarks owned by The Institute of Electrical and Electronics Engineers,
Incorporated.
5NFPA publications are published by the National Fire Protection Association (https://w ww.nfpa.org/) .

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

3. Definitions, acronyms, and abbreviations

3.1 Definitions

For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary
Online should be consulted for terms not defined in this clause. 6

gutter: An enclosure made of sheet metal (metallic auxiliary gutter) or a flame-retardant, non-metallic
materials (non-metallic auxiliary gutter) used to supplement wiring spaces in electrical equipment such as
distribution centers, switchgear, switchboards, meter centers, etc. The enclosure has hinged or removable
covers for ease of wire/cable installation and for protection to the wires inside. The enclosure is designed for
conductors to be laid out or set in place after the enclosures have been installed.

luffing: The process of pulling slack cable in a midway point of a cable pull to reduce tension and minimize
side wall pressure on the cable

maintained space: A method of installation in power cable trays that provides spacing between adjacent cables
and allows for air circulation to avoid having to de-rate the cables for ampacity. Cables without maintained
spacing are considered installed in a random fill manner.

NOTE—See item g) in 4.3.1 for additional information.7

mare’s tail: Pulling device made of high strength flat fabric braid that is woven around the cable. It usually
consists of four straps

minimum pulling bend radius: The minimum allowable value of the radius of an arc that an insulated
conductor, insulated wire, or insulated cable can be bent under tension while the cable is being installed.

minimum training bend radius: The minimum allowable value of the radius of an arc that an insulated
conductor, insulated wire, or insulated cable can be bent under no tension for permanent installation.

random fill: Cables installed in trays in a non-spaced, non-grouped configuration.

rolling friction: The resistance to motion when pulling around a bend after cable movement has begun. Syn:
dynamic friction.

standing friction: The resistance to motion to overcome the inertia or weight and start a cable moving. Syn:
static friction.

3.2 Acronyms and abbreviations

Al aluminum

AWG American wire gauge

cmil circular mils

CPE chlorinated polyethylene

CSPE chlorosulfonated polyethylene (a.k.a. Hypalon™)

Cu copper

6IEEE Standards Dictionary Online is available at: http://d ictionary.ieee. org. An IEEE Account is required for access to the dictionary,
and one can be created at no charge on the dictionary sign-in page.
7Notes in text, tables, and figures of a standard are given for information only and do not contain requirements needed to implement this
standard.

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

EMI/RFI electromagnetic interference/radio frequency interference

EPDM ethylene propylene diene monomer

EPR ethylene propylene rubber

HMWPE high-molecular-weight polyethylene

Hi-Pot high-potential test

kcmil one-thousand circular mils

LAN local area network

LSZH low smoke zero halogen

MAPT maximum allowable pulling tension

NBR nitrile butadiene rubber (a.k.a. polychloroprene or Neoprene™)

NEC National Electrical Code

NESC National Electrical Safety Code

OD outside diameter or overall diameter

OSHA Occupational Safety and Health Administration

PE polyethylene

PPE personal protective equipment

PPT projected pulling tension

PVC polyvinyl chloride

SAF slope adjustment factor

SR silicone rubber

SWBP sidewall bearing pressure (a.k.a. sidewall pressure)

TP thermoplastic

TPE thermoplastic elastomer

TRXLPE tree-retardant cross-linked polyethylene

TS thermoset

UV ultraviolet

XLPE cross-linked polyethylene

XLPO cross-linked polyolefin

4. Planning the pull

4.1 Cable storage, handling, and re-reeling

Cables should be stored on reels that are in an upright position on their flanges and handled in such a manner
so as to help prevent physical damage to the reel and deterioration of the cable. Cable reels weighing less than
18 kg (40 lb) and smaller than 610 mm (24 in) that can be handled by one person alone are often shipped and
stored flat on their flange for convenience. Normally cable is stored in a sheltered area such as a warehouse
with both ends of the cable sealed against moisture or contamination. Cold or heat shrinkable end caps are the
preferred method of sealing. In the past, tape has been used to seal cable ends, but it is no longer the preferred
method due to its limited durability and non-uniform application. Reels should be blocked to help prevent

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

inadvertent damage, which can occur due to contact between the flanges of adjacent reels. When cables are not
immediately planned for installation, the cable should be protected by the application of wood lagging or other
suitable materials across the reel flanges.
When outdoor storage is necessary, the cable should be stored on pallets or on plywood in order to keep the
reels off the ground or on a flat, solid (properly drained) concrete or gravel surface to help prevent reels from
sinking into the earth. The cable ends should be sealed with end caps to help prevent moisture intrusion. The
cable should be covered with an opaque covering to help reduce cable degradation due to direct sunlight and
exposure to weathering.
Poor storage or failure to properly seal cable ends may result in condensation, moisture, or water inside the
cable. If this condition is detected, then the cable should be dried out before use by either applying a vacuum to
the cable or purging the cable with dry nitrogen. Consult the cable manufacturer for more information on the
recommended method for inspecting, detecting, and remedying moisture ingress.
Often, cable is re-reeled at the job site to accommodate cable pulling setup space limitations or to make
handling easier. Whenever cable is re-reeled, care should be taken so that the minimum cable bend radius
is not violated by the use of a cable reel that has a drum diameter that is smaller than twice the minimum
cable bend radius for the cable construction. Consult NEMA WC 26 [B80] for information about minimum
allowable drum diameters.8
Cable reels can be easily damaged by improper forklift handling during transit and handling or on the jobsite
during installation or storage. Cable damage caused by improper handling is often not visible and can be
several layers below the surface. The following figures are illustrative examples of proper and improper
methods of cable reel handling.
Figure 1, Figure 2, and Figure 3 show the proper handling of cable reels using a forklift.

Courtesy of Dekoron Wire and Cable Company, LLC
Figure 1—Lift reel with both flanges

8The numbers in brackets correspond to those of the bibliography in Annex H.

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

Courtesy of Dekoron Wire and Cable Company, LLC
Figure 2—Lift reel using pallet

Courtesy of Dekoron Wire and Cable Company, LLC
Figure 3—Lift reel under bottom flange
Figure 4, Figure 5, and Figure 6 show improper handling of cable reels.

Courtesy of Dekoron Wire and Cable Company, LLC
Figure 4—Do not nail into reel flanges

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

Courtesy of Dekoron Wire and Cable Company, LLC
Figure 5—Do not stack material on the top of the reel

Courtesy of Dekoron Wire and Cable Company, LLC
Figure 6—Do not lift reels by the top flange

Staging or storing cable in a figure eight configuration should be avoided. The small cross-sectional area
created by crisscrossed cables results in discrete pressure points where maximum sidewall bearing pressures
(SWBPs) can be exceeded when cables are stacked in a figure eight configuration. See 6.11 for more
information on this subject.
4.1.1 Specialty cables
While the bulk of the cable in generating station and industrial applications has been conventional power,
control, and instrumentation cable, the handling and storage of certain specialty cables warrants additional
attention due to their construction and their more frequent use. This group includes, but is not limited to,
category data cable, coaxial cable, tri-axial cable, twin-axial cable, Ethernet cable, and telephone cable. For
installation of fiber optic cables, which also warrants special attention, refer to IEEE Std 1428™ [B74]. For
installation information regarding Ethernet cables see ANSI/TIA-1005-A [B26]. For installation information
regarding communication cables, refer to IEEE Std 789™ [B70].
The high-frequency performance requirements provided by many specialty cables depend upon close
manufacturing tolerances to provide uniform impedance as a function of length. The user is recommended
to use handling techniques that do not distort the cable or alter the relative position of cable components
because such changes create impedance anomalies. Such anomalies increase attenuation, cross-talk, and
signal reflection. Improper installation may also distort the cable’s shielding system, which can increase cross-
talk and, in general, reduce the overall signal-to-noise ratio.
The following guidance is general. Users should consult their cable manufacturer for specific applications and
for guidance for cable types not addressed by this document.

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

Specialty cables should be adequately protected prior to installation so that their high-performance
requirements have not deteriorated. Such cables are typically more susceptible to degradation during storage
than ordinary power and control cables because of their construction. Like all other cables, both ends of the
specialty cables should be sealed to protect the cable against moisture ingress. Cold or heat shrinkable end
caps are the preferred method of sealing. Tape has been used in the past to seal cable ends, but is not the
preferred method due to the reasons mentioned above.

Specialty cable should always be stored indoors. However, when temporary outdoor storage is necessary
especially when being installed in duct banks, trenches, or by direct burial, the reels should be protected from
ultraviolet (UV) light damage through the use of light-weight, opaque reel covers. Storage should be on flat,
solid, well-drained surfaces. Whether stored indoors or outdoors, reels should be blocked to help prevent
inadvertent damage from contact with flanges of adjacent reels. When such cables are not immediately planned
for installation, the cable should be protected by the application of wood lagging or other suitable materials
across the reel flanges.

4.1.2 Armored cable

The National Electrical Code® (NEC®) (NFPA 70® 2017 Edition)9 defines armored cables as Type AC
(Article 320) and Type MC (Article 330). Per the NEC Type AC, Armored Cable is a “fabricated assembly of
insulated conductors in a flexible interlocked metallic armor”, and Type MC, Metal Clad Cable is a “factory
assembly of one or more insulated circuit conductors with or without optical fiber members enclosed in an
armor of interlocking metal tape, or a smooth or corrugated metallic sheath”.

Armored cable, as referred to in this document, is any one of the following cable configurations:

a) Aluminum interlocked armor

b) Galvanized steel interlocked armor

c) Continuous smooth or corrugated aluminum armor

d) Continuously welded smooth or corrugated metallic armor with or without an overall non-metallic
jacket

e) Served galvanized steel wire armor (not recognized as type MC)

f) Flat metal tape helically applied armor (not recongnized as type MC)

Even though armored cables are protected by a metallic sheath, the storage and handling requirements
including the use of end caps on both ends of the cable discussed above should be followed for both armored
and non-armored cables. Cold or heat shrinkable end caps are the preferred method of sealing. If an armored
cable does not have an overall jacket, then the cable ends should be sealed to an underlying core jacket.

4.2 Cable cold temperature limits

Low ambient temperatures can create cable handling and pulling difficulties, which vary based on the
cable construction and specific installation configuration. Generally handling or pulling cables in ambient
temperatures below –10 °C (14 °F) can cause damage to the cable’s sheathing, jacketing, or insulation. Most
cable manufacturers have installation procedures or manuals (see Anaconda-Ericsson, Inc. [B5], Anixter Inc.
[B6], CABLEC [B29], General Cable [B47], Nexans Cabling Solutions [B81], Okonite Cable [B84], RSCC
Wire and Cable [B86], Southwire Power [B88], etc.) that provide helpful information for cable installation in
cold temperatures. As a general guideline, cable should not be installed when temperatures are less than the
cold bend temperature rating of the cable plus 15 °C (27 °F), that is, minimum installation temperature = cold
bend temperature rating + 15 °C (27 °F). If ambient temperatures are expected to be below –10 °C (14 °F) in
the 24 h preceding cable handing and installation activities, the cable should be warmed to room temperature,

9Information on references can be found in Clause 2.

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IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

20 °C (68 °F), for at least 24 h before work activities begin. During cold weather installations, cable lubricants
should be used that are suitable for the ambient temperatures. In addition, to avoid damage to the cable due to
cold bending, the cable should be pulled slowly and steadily to completion (including cable training) on the
same day. In all cases, the cable manufacturer’s recommendations on minimum ambient temperature limits
during handling or installation should be followed. For further information contact the cable manufacturer.

4.3 Raceway types and fill recommendations

4.3.1 Trays

A cable tray is a raceway type that is made up of a single unit, or an assembly of units, forming a structural
system used to route cables. Cable trays come in various widths, heights, and configurations; for example,
ladder or ventilated trough, solid bottom, and basket type. Cables of all voltage classes can be installed in
cable trays provided the appropriate installation conditions for the voltage classes are followed. Specific
requirements for tray installation, maximum fill criteria and allowable ampacities can be found in the NEC,
Article 392. For additional information regarding the design of cable tray systems see IEEE Std 422™ [B63].
Some general guidelines are listed below, as follows:

a) The maximum allowable cable weight that can be supported within a tray should be based on the
analysis of the tray and its support system.

b) Cable should be installed no higher than the top of the cable tray side rails for non-covered trays; lower
for covered cable trays. Exceptions exist such as at intersections and where cables enter/exit the cable
tray over the side rails.

c) Smaller size cables such as control, instrument, specialty, and fiber optic cables may be mixed in
the same tray on a random fill basis when electromagnetic interference/radio frequency interference
(EMI/RFI) issues among the cables are not a concern.

d) Low voltage power, control, instrumentation cables, specialty, and fiber optic cables are secured to
tray rungs in a random fill manner, but should be installed in as neat and uniform manner as possible.
However, they are normally not layered in neat rows or secured in place like maintained space cables.
This results in cable crossings and void areas, which take up some of the tray’s usable cross-sectional
area. The cable tray fill limit for random filled trays is calculated to be a percentage of cable tray
usable cross-sectional area. A 30% to 40% fill for power and control cable and 40% to 50% fill for
instrumentation, specialty, and fiber optic cables will generally result in a tray loading so that no cable
will be installed above the top of the side rails of the cable tray except at intersections and where cables
enter or exit the cable tray systems. See NEC, Article 392.22 for cable tray fill criteria.

e) The percent fill of a tray is the sum of the cable cross-sectional areas divided by the tray cross-sectional
area times 100%; thus % fill = ∑ cable cross-sectional area ÷ tray cross-sectional area × 100%.

f) Where single conductor low voltage non-shielded cables are used in trays for power circuits, these
conductors should be securely bound in circuit groups (triangular, triplex, bundled, etc.) to help
prevent excessive movements due to conductor-to-conductor fault-current electromagnetic forces and
to reduce inductive heating effects in tray sidewalls and bottom.

g) Where single conductor shielded medium voltage power cables sizes 1/0 AWG and larger are installed
in trays, the conductors may be arranged in a single layer with cables touching, in a single layer with
maintained space (usually one full cable diameter spacing between conductors), or in triangular,
triplex, or quadraplex configurations bound together in circuit groups where the sum of the cable
diameters does not exceed the tray width. See NEC, Article 392.22 for guidance regarding cable
installation and cable ampacity, respectively.

h) Information on ampacity for cables installed in cable trays without maintained spacing and various
cable tray fill depths can be found in NEC, Article 392.80 and ANSI/NEMA WC 51/ICEA P-54-440
[B16].

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IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

4.3.2 Conduits, wire ways, and ducts

Conduits, wire ways, and ducts are common terms for enclosed raceways. Wire ways, which are usually
rectangular, are sheet metal troughs with hinged or removable covers for routing and protecting electrical
wires and cables. Conduits and ducts are tubular conveyances for protecting and routing electrical wires and
cables. The term “duct” is typically used for underground raceways while the term “conduit” is normally used
inside a building. More detailed guidelines are as follows:

a) NEC, Chapter 9, Table 1 shows conduit cross-sectional fill limits of 53%, 31%, and 40% for one, two,
and three or more cables respectively. These fill limits are applicable for power, control, instrument,
specialty, and fiber optic cables, and have been used for both conduits and ducts. Even though these
fill limits are widely accepted and have been used for years, exceptions exist for instances where the
conduit/duct path is short, straight, or where the cable can be pushed through the conduit or duct by
hand. For more information regarding the design of conduit and ducts see IEEE Std 422 [B63].

b) For wire ways, the sum of the cross-sectional areas of all conductors/cables in the wire way should not
be greater than 20% of the interior cross-sectional area of the wire way per NEC, Article 376.22(A).

c) The percent fill of a conduit or duct is the sum of the conductor/cable areas divided by the useable
conduit or duct area times 100%; thus % fill = ∑ conductor/cable area ÷ internal conduit area × 100%.

4.3.3 Troughs, gutters, and sleeves

Gutters are metal or plastic enclosures used to route and protect conductors or cables in meter centers, load
distribution centers, switchboards, motor control centers, and other similar cabinets or panels. These items
are used as a part of a complete assembly of electrical equipment to supplement wiring space by enclosing
conductors and cables that are used as feeders or branch circuit conductors. Gutters are not designed or certified
to enclose bus bars, switches, over current devices, or other equipment. Section 12–1900 of the Canadian
Electric Code [B32] limits the length that gutters are allowed to extend beyond the equipment that they support
to a maximum of 2.0 m (6.6 ft). In addition, the CEC requires gutters to be supported throughout their entire
length at intervals not more than 1.5 m (5 ft). NEC, Article 366.30 requires that metal auxiliary gutters be
supported and secured throughout their entire length at intervals not exceeding 1.5 m (5 ft). For nonmetallic
gutters the interval is not to exceed 900 mm (3 ft) and at each end or joint, and in no case the distance between
supports exceed 3 m (10 ft).

There is no maximum established fill limit for troughs or sleeves because these raceway types are normally
straight and short in length, and the cables are either placed into them or pushed through them. For gutters,
NEC, Article 366.22 (A) states that “the sum of the cross sectional areas of all contained conductors and cables
at any cross section of a gutter shall not exceed 20 percent of the interior cross-sectional area of gutter.”

4.3.4 Duct banks

Many of the same considerations for installing cables in conduit apply to installing cables in underground
duct bank systems. However, there are unique installation considerations for underground duct banks that
need to be considered. When done prior to plant startup, other cables in the same location are usually de-
energized. However, after plant startup and during retrofit work, vaults, duct banks, hand holes, and manholes
often contain other cables that are energized and cannot always be de-energized during the new work activity.
Work under these conditions requires an added level of caution and extra safety measures to be considered
and included in the planning prior to performing this type of work. These pulls often have the same problems
as conduit pulls, plus the added difficulty of having to work in an enclosed or confined space at one or both
ends, with other nearby energized cables. When the size of the manhole opening does not allow the setup of
the pulling rig or the cable reel at the duct opening, extra rigging is required to guide both the pulling rope
and the cable from outside the manhole into the duct or conduit. The minimum bending radius and maximum
sidewall pressure requirements, for the cables being installed in these raceway types should not be violated.
For information regarding the design of duct bank systems see IEEE Std 422 [B63].

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IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

There are many potential problems when working in a manhole/vault environment. Duct banks, hand holes,
manholes, and vaults are often below ground and may accumulate standing water, which requires pumping the
water out and disposing of contaminated discharge. Vaults and manholes are considered confined spaces that
require special permits and extra safety precautions. The atmosphere in confined spaces requires monitoring
for oxygen, toxic gases, and explosive gases. Work in confined space areas requires that personnel not work
alone but in a minimum of pairs, with emergency rescue devices readily available to extract personnel should
an accident happen. Also, manholes are often located where traffic and other above ground obstructions
restrict the available work space.

It is considered an unsafe practice to have personnel in the “exit” manhole during a cable pull because pulling
tensions can become high, and if a pulling line, block, or cable grip fails, a rapid release of cable tension can
create a missile hazard in that manhole. Blowing a “pig” through the duct when cleaning the duct can also
result in a hazard in the exit manhole. It is usually necessary to have personnel in the “feeding” manhole to
apply lubricant to the cable as it enters the conduit. The pulling tensions at this location are not high enough to
cause personnel injury should an equipment failure occur.

WARNING

Personnel should never stand in the exit manhole during a pull because high pulling tension can create a
missile hazard if a pull line, block, or cable grip should fail.

4.3.5 Direct burial

Direct burial is a technique used for routing cable without a conduit or duct bank in which the cable is in
direct physical contact with earth. The cable should be buried below the frost line. For direct buried cables,
bedding sand or a bed of soil, a physical barrier on top, and a marker tape are recommended. As an example,
this method is often used for parking lot lighting where the consequences of interruption due to future digging
are minimal. This method should not be used in areas of heavy vehicular (truck) traffic or where there is a high
density of underground infrastructure. When the direct burial method is used in areas of heavy truck traffic,
proper design/calculations for dissipation of load, protection via concrete cap, etc. is necessary to preclude
cable damage. When cable is laid in an open trench, precautions should be taken to lay the cable on bedding
sand or a bed of soil that does not contain debris or sharp rocks and to cover the cable with similar soil. It is
recommended that the cable be designed or rated for direct burial. Cable trenching machines are available that
slice an opening in the surface, feed the cable into the opening, and cover the opening in one step, also known
as “plowing”. Caution must be exercised when using this technique to verify that the area is clear of other
buried cable or utilities to avoid damaging these in service items.

4.3.6 Trenches

A trench is a term used for two different types of installations. The first, an open trench, is a form of direct
burial in which an excavation or depression in the ground is generally deeper than it is wide (as opposed to a
gully, or ditch), and narrow compared to its length. The second is a trench, made typically of concrete although
other materials may be available, which is a long narrow ditch with concrete on the sides, has an open bottom
for water drainage, and is covered by a removable steel or concrete lid. Trench covers are available in both
man-rated and vehicle-rated types. The advantage of the concrete trench is the ability to remove the cover to
inspect, repair, or replace damaged cable or to add new cable as conditions warrant. Cost and schedule may
be disadvantages to the concrete trench design depending on the length, capacity, construction materials, and
labor. Another disadvantage of trenches is that, over time, they usually accumulate water and dirt in them.
However, trenches can be sloped and designed to overcome this issue.

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4.3.7 Raceway support types
The type of support device to be utilized is dependent upon whether the raceway is conduit, tray, or free air.
The support should be designed and installed to carry the maximum cable load considering the seismic zone
where the facility is located. Engineering usually produces typical support details applicable to most plant
areas for the installer to use; however sometimes special support details are needed due to unique installation
situations. See 8.2 for more information relative to cable supports.

4.4 Planning activities
The following activities should be considered prior to performing any work:

a) For long conduit or duct bank pulls, preplan the direction of cable pulls by performing cable pulling
calculations in both directions.

b) Plan to have sufficient cable, pulling lubricants, and cable pulling accessories (shims, sheaves, rollers,
ropes, etc.) available prior to performing any work.

c) Plan duct inspection and cleaning activities sufficiently in advance of cable pulling activities in order
to determine the suitability of the ducts for use.

d) Plan confined space inspection and test activities for combustible and toxic gases, water, and energized
cables sufficiently in advance to make necessary preparations.

e) Plan to check cable clearances by doing jamming calculations, bend radius calculations, and sidewall
pressure calculations prior to any cable pulling.

f) Plan the cable setup area to be sure that it is of sufficient size to accommodate the equipment needed.
This should also help ensure the pulling equipment can be located to support the planned pull.
Sometimes physical constraints will only allow pulling from one direction.

g) For installing cables in trays, walk down the tray route to assure it is complete, contiguous, and does
not contain debris or foreign material.

h) Avoid routing cables near lube oil reservoirs, lube oil conditioners, hydraulic oil storage areas, etc.,
since potential leakage of petroleum products can affect cable jacket, shield, and insulation materials.

i) Avoid routing cables near hot pipes (even insulated pipes) as the heat from pipes can cause accelerated
aging to localized cable areas, which can lead to long-term failure points.

j) Avoid routing cables in areas subject to damage due to future maintenance activities. If it is required to
run cables through these areas, proper physical protection will need to be provided.

k) As required under NEC, Article 300.8, “raceways or cable trays containing electric conductors shall
not contain any pipe, tube, hose, or equal for steam, water, air, gas, drainage, or any service other than
electrical.”

l) Cables should only be installed in a raceway system that has adequately sized bends, boxes, fittings,
and pull points so that the manufacturer’s minimum allowable bending radius and sidewall pressure
limits are not exceeded.

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4.5 Pre-installation activities for duct banks

4.5.1 General

The following pre-installation activities should be performed before any cable pulling begins:

a) If possible, turn off existing energized cables and ground all de-energized phase conductors at the load
end to be sure that there are no residual charges built up on cable shields or sheaths.

b) Monitor the air inside manholes and vaults for toxic and combustible gases.
c) Ventilate manholes and vaults and re-check air for toxicity and combustible gas levels.
d) Dewater manholes and vaults.
e) Wear appropriate protective clothing including rubber gloves, boots, respirators, harnesses, etc., when

entering manholes and vaults.
f) Inspect the entrance of all ducts for evidence of sharp edges; inspect existing cables for evidence of

cable deterioration; identify any spare ducts; and, in general, examine the condition of the manhole or
vault.
g) Bore, rod, and thoroughly clean all empty conduits/ducts with boring and cleaning mandrels followed
by a test mandrel with soft covering. A boring mandrel dislodges and removes the debris not removed
by the rodding operation and re-bores a duct to remove duct blisters, roots, concrete stalactites, etc.
The cleaning mandrel is normally used after the rodding operation to provide a clear and clean duct for
cable pulling. Inspect and repair, as necessary, each duct and conduit prior to starting any cable pulling
activities.
h) Upon removal of the mandrel inspect the soft covering. Evidence of damage to the soft covering such
as tears or rips indicate sharp edges or obstructions inside the duct and should be further investigated
before pulling cable into the duct. Normally the boring and rodding activities are repeated until the
mandrel with a soft covering shows no signs of damage. Test mandrels are used to determine the duct
bend radii of the duct system, to check ducts for out of roundness, and to check surface roughness in
preparation for cable pulling. A borescope may also be used to examine the inside of the duct to locate
the sharp edges and obstructions inside the duct or to confirm that the sharp edges have been removed.
i) Lubricate existing cables and conduits/ducts and let soak for 24 h before pulling existing cables out
during cable replacement activities. The use of power lubrication equipment is the most effective
technique as it forces the lubricant further into the conduit/duct and covers the interior of the conduit/
duct and cable more thoroughly.
j) Inspect existing cables that are being removed to identify installation damage that may be a clue to the
conduit/duct’s inner condition.
k) Review safety requirements that must be adhered to before beginning work in enclosed spaces such as
manholes or vaults.
l) Because manholes and vaults are considered confined spaces, comply with Occupational Safety and
Health Administration (OSHA) and other applicable safety codes and standards before entry.

WARNING

Always monitor air inside manholes and vaults for combustible and toxic gases, ventilate prior to entering
manholes and vaults, and use appropriate personal protective equipment (PPE).

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4.5.2 Duct damage
The kinds of duct damage that could be encountered include the following:

a) Silt and debris in spare ducts left over from original construction.
b) Protrusions into ducts at joints from concrete, tree roots, broken PVC ducts, earth settlement, etc.
c) Collapsed or oval shaped conduits/ducts due to poor construction practices or heavy equipment

driving over the top of the duct bank.
d) Conduits/ducts misaligned at joints due to earth settling or poor installation practices.
e) Too small bend radius in the spare conduit/duct route for the new cable to be installed.

When any of the above conditions is present, duct bank rework or repair is required before pulling cable. If any
of the conditions noted above are extreme, a new cable route may need to be designed.

For duct bank systems that were constructed of concrete-asbestos (transite), pulling cables, cleaning ducts,
and removing cables is difficult because the duct absorbs moisture, “swells”, and becomes “friable”. This is
a particular concern because it is constructed with asbestos. It is recommended to avoid disturbing concrete-
asbestos duct banks and cables therein, and looking for another route for new cables.

4.5.3 Manhole damage
The kinds of manhole or vault damage that could be encountered include the following:

a) Manhole lid or seal damaged
b) Broken or rusted ladder rungs, ladder supports or loose anchor bolting
c) Corrosion of cable racks, trays, or metallic conduit
d) Corrosion of metallic cable clamps or metallic portions thereof
e) Broken rungs and sharp edges on trays or conduit
f) Degradation, deterioration, or evidence of rodent damage to cable
g) Evidence of electrical arcing from existing cables to racks, trays, ducts, other metallic objects
h) Loose connections or corrosion at the ground wire terminal point inside the manhole or vault

When any of these conditions are present, manhole or vault repair or replacement is required before pulling
cable.

4.5.4 Cable installation precautions
The following installation precautions should be observed:

a) Ventilate and retest the vault or manhole for toxic gases prior to entering.
b) Use suitable pulling eyes, basket grips, and ropes for the size and weight of the cable being pulled.
c) Use suitable sized shims, sleeves, rollers, etc. to avoid violating the cable minimum bend radius,

maximum pulling tensions, or maximum sidewall pressures.
d) Avoid pulling cables into a duct with existing cables due to the potential for cable damage.
e) Due to the potential for cable damage, avoid pulling cables of different types and sizes together in

the same conduit/duct; however, sometimes a ground conductor of a different size is pulled with the

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phase conductors. When a separate ground conductor is pulled in with single phase conductors, it is
recommended to use an insulated ground conductor to avoid a bare ground conductor from doing
damage, such as scraping the insulated phase conductors during the installation process. Unless the
ground conductor is the same size as the phase conductors being pulled, it should not be part of the
cable conductors being pulled on. The ground wire should only “go along for the ride”. Its weight
contribution should be included in the total cable weight when performing pulling calculations.
f) Pre-lubricate ducts with copious amounts of a lubricant that is compatible with the cable jacket.
g) Lubricate each cable with more lubricant as it enters the duct.
h) Monitor cable pulling tensions during the pull.
i) Avoid starts, stops, and jerking the cable during the pull as this leads to cable galloping.
j) Pre-warm cable when pulling cable in cold temperatures (See 4.2).
4.5.5 Cable rigging activities
Rigging, including bull wheels and skids, should be carefully selected so that cable pulling tensions, sidewall
pressures, and bending radius limits are not exceeded. Pulling rigs should be properly braced to help prevent
movement. The pulling ropes, blocks, tackles, bracing, and shackles should have a rating sufficient to meet
the tension demands of the cable pull. For example, a pulling rope with a tension of 44 500 N (10 000 lbf) will
apply 89 000 N (20 000 lbf) of tension to a block with a 0° angle or 63 000 N (14 140 lbf) at a 90° angle (see
Figure 7).

Figure 7—Wheel setup comparisons

The rigging should be set up to bring sufficient cable into the manhole for splicing. Stopping a pull to later pull
(luffing) additional cable into the manhole works against standing friction rather than rolling friction, which

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can greatly increase the cable’s pulling tension. For the same reason if the cable is pulled through manholes,
cable guides should be set up to position the cable as it goes through this manhole, rather than pulling (luffing)
slack cable back into the manhole.
Typical duct bank cable pull set-ups are shown in Figure 8 and Figure 9. Three-wheel pulley assemblies, shown
in Figure 8 are often used when pulling cables because they are smaller and more practical for areas of limited
space. However, it should be recognized that a three-wheel pulley assembly does not provide as smooth a bend
as a single-wheeled pulley of a larger size and can create a higher sidewall pressure on the cables being pulled.

Figure 8—Duct bank pull setup—Example 1

Figure 9—Duct bank pull setup—Example 2
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4.6 Distance limitations
The maximum distance a cable may be pulled in a raceway (i.e., tray or conduits/ducts), without subjecting the
cable to damage, depends on a combination of the following conditions:

a) Conductor material (copper or aluminum)
b) Size of conductor
c) Weight of conductor/cable
d) Number of conductors
e) Maximum allowable pulling tension (MAPT) (i.e., tensile strength of conductor or jacket, or both)
f) Maximum allowable SWBP of the cable construction
g) Cable pulling methods (placed by hand, with pulling eyes, using basket weave grip, etc.)
h) Size of conduit, duct, or tray
i) Percentage fill of raceway
j) Number and configuration (single conductor, triplex, or multi-conductor) of cables to be pulled
k) Number, location, and radius of bends
l) Angle in degrees and direction of bends (e.g., horizontal or vertical)
m) Slope of raceway (tray, conduit, or duct)
n) Coefficient of friction between cable jacket and raceway surface (tray bottom or conduit walls)
o) Amount and type of lubrication used
p) Limits of cable pulling and reel handling equipment
q) Use of any shims, rollers, sheaves, etc. to reduce friction
r) Amount of reel back-tension from payoff reel
s) Direction of pull

For more information see pulling guides from equipment manufacturers and installation guides from cable
manufactures; such as Anaconda-Ericsson, Inc. [B5], Anixter Inc. [B6], General Cable [B47], Nexans Cabling
Solutions [B81], Okonite [B84], Southwire Power [B88], RSCC Wire and Cable [B86], CABLEC [B29].

To determine the maximum pulling length for a cable or bundle of cables, it is necessary to determine the
maximum allowable values for both the pulling tension and sidewall pressure. The pulling length is limited by
one or both of these factors. See 4.10, 4.11, and 4.14 for more information on these subjects.

4.7 Reel position and reel back tension
Pulling tension will be increased when the cable is pulled incorrectly off of the reel. Turning the reel and
feeding slack cable into the tray, conduit, or duct entrance will reduce the pulling tension and may change a
difficult pull to an easy one.

Reel back-tension is the amount of force required to pull the cable off of the reel. The tension required to pull
cable from a reel will depend on the cable size, the weight of the first lap of the cable on the reel, the stiffness of
the cable, and the type and condition of the reel payoff stand used. For purposes of this recommended practice,
the tension force can be approximated for pulling a cable off of the reel in a horizontal position as shown in

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Equation (1)10. For more information see the Committee Report entitled “Recommended Practice on Specific
Aspects of Cable Installation in Power Generating Stations” [B31]:

Tr ≈ K0 ×W ×L× g (metric)
Tr ≈ K0 ×W ×L (1)

(English)

where:

Tr is the tension from cable reel, N (metric), lbf (English)
W is the weight per unit length of cable, kg/m (metric), lbf/ft (English)
L is the length of cable, m (metric), ft (English)
g is the acceleration due to gravity constant (9.8 m/s2) (metric)

K0 is the basic coefficient of friction (both: typical value between 0.5 to 1.0
for more information see IEEE Std 525™ [B65], Fee and Quist [B44], and Weitz [B93])

To assure proper force for pulling cable off of the reel, a reel drive device such as power reel rollers, motorized
payoff stands, or adequate manpower should be used. Freewheeling the cable or cable reel during the pull and
long vertical distances between the payoff reel and the entrance point of the cable system should be avoided. A
payoff system equipped with braking ability will be most effective in controlling cable back-tension. Tension
caused by removal of the cable from a reel or simply the dead weight of the cable traversing a long vertical
rise to the entrance point of the system will be magnified as the cable passes through bends in the system. This
will shorten the ultimate length of cable that can be pulled without exceeding the cable maximum physical
limits. For light gauge or fragile cable, (i.e., specialty or fiber optic cable) practically zero back-tension may be
necessary to help prevent damaging the cable. To better control tension, one person is used to un-reel the cable
while another person feeds it into the first raceway component. Payoff reel back-tension should be considered
when calculating the total tension developed during the installation.

Courtesy of RSCC Storage and Instruction Manual for RSCC Wire and Cable [B86]

Figure 10—Payoff reel positioning

Positioning of the payoff reel can also be critical. The closer the payoff reel and the more it is in line with
raceway elevation to reduce cable direction change, the lower the pulling tension will be to start the cable pull.
To reduce cable payoff reel tension, follow the natural curvature of the cable on the reel and feed the cable into
the raceway in as straight and level manner as possible, as shown in Figure 10.

4.8 Bend location
The location of bends in the raceway system has a large influence on the preferred direction of pulling cables.
Whenever a choice is possible, pull the cable so that bends are closest to the reel. It is less desirable to pull a
cable out of a bend at or near the end of a long run. When this is not possible and a bend is at or near the end of
the cable run, be cognizant that pull tensions, as well as SWBPs, will be higher than if the cable were pulled in
the opposite direction.

10Equation (1) courtesy Committee Report [B30].

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4.9 Minimum bend radius

In order to help prevent cable installation damage and for long-term reliability, it is necessary to adhere to
the manufacturer’s minimum pulling/training bend radius values, maximum pulling tensions, and maximum
SWBPs. These three criteria are interrelated. Violating the minimum pulling bend radius values when cable
is being pulled, not only can damage the cable, but it produces greater pulling tensions and higher SWBPs.
Depending on the pulling tension, a larger than the minimum pulling-bend radius value may be required to
limit the sidewall pressure to a value below the manufacturer’s maximum limits. The relationships between
pulling tension, SWBP, and pulling bend radius are discussed in 4.10 through 4.14. Minimum trained bend
radius numbers are only applicable when the cable/wire is under no tension and is bent into final position
for long-term use. As shown in Table 1, non-shielded, non-armored cables typically have minimum trained
bend radius multipliers that vary between 4 to 7 times the outside diameter (OD) of the cable, and minimum
pulling cable bend radius multipliers that vary between 7 to 10 times the OD of the cable. Per Table 2, the
trained cable bend radius multiplier for shielded and armored cable can vary from 7 to 15 times the cable OD
and the pulling cable bend radius multiplier can vary from 7 to 18 times the cable OD based on factors such
as the cable construction and shield/armor type. The bend radius values (see Figure 11) are measured from
the inner surface of the cable and not from the cable center axis. Table 1, Table 2, and Table 3 are shown for
illustration purposes using typical values, and may not be applicable to some cable constructions. Thus, the
user is encouraged to consult the cable manufacturer for specific bend radius values prior to beginning any
cable pulling activities.

Table 1—Minimum bend radius multipliers for non-shielded or non-armored cable

Cable with insulation thickness Minimum training radius as a Minimum pulling radius
< 4.32 mm (0.169 in) multiple of cable OD as a multiple of cable OD
(no tension)*
(under tension)*

Cables, 25.4 mm (1.0 in) OD and less 4 7

Cables, greater than 25.4 mm (1.0 in) to 5 8
50.8 mm (2.0 in) OD

Cables, greater than 50.8 mm (2.0 in) OD 6 9

Cable with insulation thickness Minimum training radius as a Minimum pulling radius
≥ 4.33 mm (0.170 in) multiple of OD as a multiple of OD
(no tension)* (under tension)*

Cables, 25.4 mm (1.0 in) OD and less 5 8

Cables, greater than 25.4 mm (1.0 in) to 6 9
50.8 mm (2.0 in) OD

Cables, greater than 50.8 mm (2.0 in) OD 7 10

*For cable that is not round, the OD to be used is the circumscribing diameter.

Courtesy of Anixter, Canada
Figure 11—Example measuring bend radius

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Table 2—Minimum bend radius multipliers for shielded or armored cable

Cable type Minimum training radius Minimum pulling radius
as a multiple of cable OD as a multiple of cable OD

(no tension)** (under tension)**

Flat Tape Armor

      Single Conductor Cables 12 12

      Multi-conductor Cables 12 12

      Multiplexed Cables 77

Smooth Aluminum Sheathed Cables

      Single Conductor Cables

            OD < 19 mm (0.75 in) 10 12

            19.1 mm (0.751 in) ≤ OD ≤ 38.1 mm 12 14
(1.5 in)

            OD ≥ 38.1 mm (1.5 in) 15 17

      Multi-Conductor Cables

            OD < 19 mm (0.75 in) 10 12

            19.1 mm (0.751 in) ≤ OD ≤ 38.1 mm 12 14
(1.5 in)

            OD ≥ 38.1 mm (1.5 in) 15 17

      Multiplexed Cables

            OD < 19 mm (0.75 in) 68

            19.1 mm (0.751 in) ≤ OD ≤ 38.1 mm 7 9
(1.5 in)

            OD ≥ 38.1 mm (1.5 in) 9 11

Interlocked Tape or Corrugated
Armored Cables

      Single Conductor Cables 79

      Multi-conductor Cables 79

      Multiplexed Cables 57

Served Wire Armored Cables

      Single Conductor 8 10

      Multi-conductor 8 10

      All Other Types 12 14

Other

Type MC smooth metallic armor, 19 mm 10 12
(0.75 in) OD and less

Type MC smooth metallic armor, greater than 12 14
19 mm (0.75 in) to 38 mm (1.5 in) OD

Type MC smooth metallic armor, greater 15 18
than 38 mm (1.5 in) OD

Overall shielded cables (with or without MC 12 14
smooth sheath), 38 mm (1.5 in) OD and less

Overall shielded cables (with or without MC 15 18
smooth sheath), greater than 38 mm (1.5 in)
OD

Cables with individually shielded conductors 7 × OD of cable 10 × OD of cable
(unarmored)

Cables with individually shielded conductors 7 × OD of cable or multiplier 10 × OD of cable or
(armored) for armor, whichever is greater multiplier for armor,
whichever is greater

Table continues

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Table 2—Minimum bend radius multipliers for shielded or armored cable (continued)

Cable type Minimum training radius Minimum pulling radius
as a multiple of cable OD as a multiple of cable OD

(no tension)** (under tension)**

Braided stainless steel or braided bronze armor 8 10

Served galvanized steel wire armor 12 14

Flat metal tape armor helically applied 12 14

Tape shield; no armor 12 14

Wire shield, no armor 8 10

**For cable that is not round, the OD to be used is the circumscribing diameter.

Table 3—Instrumentation and specialty cable minimum bend radius multipliers

Minimum training radius Minimum pulling radius

(no tension) as multiple (under tension) as

of cable OD multiple of cable OD

Category cable, 4-pair, unshielded 4 8

Category cable, 4-pair, with overall 10 14
shielded

Category cable, 6-pair, unshielded 8 12

Category cable, 6-pair, shielded 10 14

Twisted pairs, shielded with metalized 6 12
polyester shield

Multiple-conductor cables or twisted pairs 12 24
with overall shield, flat or corrugated tape

Coax, twin-axial, tri-axial 8 12

Telephone (aluminum/polyester foil tape 10 20
shielded)

Telephone (braid shielded) 10 20

Armored cables should be carefully installed so that their allowable bend radius is not violated during pulling
or training activities. Bends that are too tight may distort the armor and compromise the geometry and integrity
of the cable core’s jacket and/or insulation. Recommended minimum bend radius factors, in multiples of the
cable’s OD, are provided in Table 2.

The recommended minimum bend radius for armored cables while under pull tension is larger than for non-
armored cables of the same conductor size, with the same number of conductors and configuration. It is
important to reiterate that the recommended minimum pulling bend radius, which is measured to the inner
cable surface of the bend (see Figure 11), may actually need to be further restricted to a larger bending radius
because the of cable’s sidewall pressure limit, which may otherwise be exceeded; refer to 4.14 for more
information.

Shielded, non-armored cables also require careful installation so that their allowable bend radius is not violated
during pulling or training activities. Bends that are too tight or continual flexing of a shielded cable may result
in shield distortion and shield lap misalignment, which can result in damage to the underlying cable core
materials or create spots of shield discontinuity.

High-performance specialty cables should be carefully installed so that their allowable bend radius is not
violated during pulling or training activities. Bends that are too tight may distort the cable cross section and
alter the impedance at that point and may also reduce the shielding effectiveness for certain designs. See
Table 3 for bend radius factors that are a multiple of the cable’s OD for instrumentation and specialty cables.

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4.10 Maximum allowable pulling tension (MAPT)

Pulling tension is typically applied to specialty cables through the use of a basket-weave grip installed over the
cable’s outer jacket. Maximum pulling tension is therefore calculated based on the cable jacket material, its
thickness, and the overall cable diameter. Equation (2) (from Vartanian and Sandler [B91]) is used to calculate
the MAPT using a basket-weave grip:

( )Tmc = π ×Ym ×tj × d j −tj (2)

where:

Tmc is MAPT, N (lbf)
Ym is the jacket tensile yield stress, MPa (lbf/in2) (see Table 4)
tj is the jacket or sheath thickness, mm (in)

dj is the jacket or sheath OD, mm (in)
π is the value 3.1416

Table 4—Jacket material tensile stress values

Jacket material Material stress (Ym)

MPa lbf/in2

CPE (chlorinated polyethylene) 6.89 1000

CSPE (chlorosulfonated polyethylene) (general purpose) 6.89 1000

CSPE (chlorosulfonated polyethylene) (heavy duty) 10.34 1500

LSZH – TS type 2 (low smoke zero halogen) polyolefin** 11.03 1600

LSZH – TS type 1 (low smoke zero halogen) polyolefin** 9.65 1400

LSZH – TP type 2 (low smoke zero halogen) polyolefin** 8.27 1200

LSZH – TP type 1 (low smoke zero halogen) polyolefin** 9.65 1400

NBR/PVC (acrylonitrile-butadiene rubber 6.89 1000
and polyvinyl chloride) (heavy duty)

PCP (polychloroprene) (general purpose) 6.89 1000

PCP (polychloroprene) (heavy duty) 10.34 1500

PE (polyethylene) 6.89 1000

PVC (polyvinyl chloride) (general purpose) 6.89 1000

SR (silicone rubber) 3.45 500

TPE (thermoplastic elastomer) 6.89 1000

XLPE (cross-linked polyethylene) 6.89 1000

XLPO (cross-linked polyolefin) 6.89 1000

*For purposes of this table, material stress is the recommended minimum yield tensile stress value.
Consult the manufacturer for specific material properties.
**See ICEA T-33–655 [B50]

For specialty, coaxial, tri-axial, and twin-axial cables, the user should consider the cross-sectional area of the
conductors and the braids even though the pulling is always done by the use of a basket-weave grip.

Table 5 provides typical maximum allowable pulling tension numbers for common coaxial cables. Consult the
cable manufacturer for specific maximum allowable pulling tensions for coaxial cables prior to beginning any
cable pulling activities.

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Table 5—Typical maximum allowable pulling tensions using basket-weave grip

Cable type Typical diameter Maximum pull tension,
mm (in) basket-weave grip N (lbf) *

RG 6 Type 8.4 (0.332) 270 (60)

RG 8 (RG 213) Type 10.3 (0.405) 356 (80)

RG 11 Type 10.3 (0.405) 535 (120)

RG 58 Type 5.0 (0.195) 90 (20)

RG 59 Type 6.1 (0.242) 115 (25)

RG 62 Type 6.1 (0.242) 135 (30)

RG 114 Type 10.3 (0.405) 645 (145)

*Cable manufacturer should be consulted if the planned pull requires pull tension values in excess
of the tensions given in this table.

Maximum pulling tension formula for coax cables using a basket-weave grip is as shown in Table 5 or may be
calculated using Equation (3). For aluminum materials substitute Kal for Kcu.

TMC = TC + TB
TC = Kcu ×nc × Ac (3)
TB = Kcu ×nb × Ab

where:

TMC is MAPT, N (lbf)
TC is the maximum pulling tension, N (lbf) based on conductor
TB is the maximum pulling tension, N (lbf) based on braid ends
Ac is the one strand conductor area, square mm (cmils)
Ab is the one braid end circular area, square mm (cmils)
nc is the number of conductor strands
nb is the number of braid ends
Kcu is 70.2 MPa (0.008 lbf/cmil) for soft annealed copper
Kal is 52.7 MPa (0.006 lbf/cmil) for 3/4 hard aluminum alloy (1350-H16)

MAPT for 4-pair category cables is limited to 115 N (25 lbf).

For power and control cable, the SWBP criteria is a limiting parameter for cable installation. Even though
specialty cables are often not rated for SWBP by their manufacturers, it is still a limiting parameter during
cable installation. Manufacturers of specialty cables frequently limit installation forces by specifying an
allowable bend radius under tension and an allowable pulling tension. Such data can be used to determine an
inferred maximum allowable SWBP (i.e., tension divided by radius).

Caution should be used when installing cables with foamed and spacer-maintained (air dielectric) insulation
systems because these are readily susceptible to crush damage. Consult the cable manufacturer for allowable
pulling tensions and minimum bend radius values for spacer-maintained air dielectric insulation systems
(see Heliflex Data Sheet HCA78–50JPL [B1], Heliax Bulletin 17800B-JC [B48], and Heliax Coaxial Cable
Selection Guide [B49]).

Typical values of SWBP are given in Table 6 for solid and foam dielectric coax, twin-axial, and tri-axial cables.

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Table 6—Typical maximum values of allowable SWBP

Cable type Typical max SWBP N/m (lbf/ft) *

Coax, twin-axial, tri-axial (foam dielectric) 2200 (150)

Coax, twin-axial, tri-axial (solid dielectric) 3000 (200)

Coax (air dielectric) 1600 (108)

*Cable manufacturers should be consulted if the planned pull requires SWBPs to exceed those given
in Table 6.

For armored cables, pull tension is typically applied through the use of a basket-weave grip installed over the
cable’s outer jacket or armor. If interlocked armor is manufactured and tested to meet UL-4 [B90] requirements,
1335 N (300 lbf) would be the corresponding tension limit for the tape armor itself. The corresponding core
withdrawal or slippage is 133.5 N (30 lbf) for a 3 m (10 ft) long sample. Unless cable tension is limited
by manually pulling with multiple installers, the cable should be gripped on core conductors as well as the
external armor or jacket. The allowable pulling tension for interlocked armor is generally limited by the core
conductors.

If the cable has continuously welded smooth or corrugated metallic armor with or without an overall non-
metallic jacket, the cable should also be gripped on core conductors as well as the external armor or jacket.

Regardless of the type of armor used, the cable manufacturer should be consulted to determine the maximum
allowable pulling tension, and if the planned pull requires pull tension values in excess of the tensions given
above.

The use of SWBP as a limiting parameter during cable installation is somewhat unique to the utility industry. A
typical SWBP limit for armored cables is 4400 N/m (300 lbf/ft) of bend radius. The cable manufacturer should
be consulted if the planned pull requires the SWBP to exceed these limits.

MAPT should be provided from the cable manufacturer or can be calculated as shown below.

a) MAPT based on pulling by conductor such as with a pulling eye is calculated using the expression in
Equation (4). For aluminum materials substitute Kal for Kcu.
Tmax = Kcu ×n× Ac (4)

where:

Tmax is the maximum allowable pulling tension N (lbf)
Ac is the conductor area square mm (circular mils)
n is the number of conductors
Kcu is 70.2 MPa (0.008 lbf/cmil) for soft annealed copper
Kal is 52.7 MPa (0.006 lbf/cmil) for 3/4 hard aluminum alloy (1350-H16)

when:

1) Maximum limitation for 1/C cables is 22 250 N (5000 lbf).

2) Maximum limitation for two 1/C cables and 3/C cables is 44 500 N (10 000 lbf) due to the uneven
distribution of forces.

3) Maximum pull tension limitations shown in items 1) and 2) above are conservative, see AEIC
CG5 [B3] for more information. Consult the manufacturer if higher pulling tension values are
required.

4) This formula does not apply to thermocouple, fiber optic, or specialty cable types.

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b) MAPT based on pulling with a basket grip applied over the cable jacket:

1) Non-shielded jacketed cables—8900 N (2000 lbf)

2) Shielded jacketed cables—4450 N (1000 lbf)

when:

3) Do not exceed tension limits of item a) above

4) Basket grip tensions shown in b) 1) and b) 2) do not apply to armored or lead-sheathed cables;
cables without an outer jacket; or specialty cable types such as thermocouple, coaxial/triaxial, or
¿EHU RSWLF FDEOHV &RQVXOW WKH FDEOH PDQXIDFWXUHU IRU WKHVH W\SHV

c) Tension forces for paralleled or cradled cables are assumed to be evenly distributed among the three
conductors only when pulling in a straight line. Because most pulls involve bends, the forces are
not evenly distributed, and it is conservative to assume that tension forces are shared by only two
conductors. Therefore, the number of conductors [value of n in Equation (4)] is equal to two for the
paralleled or cradled cable case.

d) For factory assembled triplexed cable, the value of n is 3. Due to the triplexed cabling of the conductors,
the pulling force will distribute evenly, and the factory assembled triplexed cable should be treated
the same as a multi-conductor cable with regard to pulling tension, sidewall pressure, and weight
correction factor.

4.11 Expected pulling tension

The expected pulling tension of one cable in a straight horizontal section of conduit or duct may be calculated

from Equation (5). This formula does not consider slope, prior tension, or the weight correction factor. If
weight correction factor (see 4.13) is applicable replace K0 by K a , where K ′ = K0 ×Wc .

T = L×W ×K0 × g (metric) (5)

T = L×W ×K0 (English)

where:

T is the total pulling tension, N (metric), lbf (English)
L is the length of conduit runs, m (metric), ft (English)
W is the weight of cable(s) per unit length, kg/m (metric), lbf/ft (English)
K0 LV WKH EDVLF FRHI¿FLHQW RI IULFWLRQ ZKLFK KDV QR XQLWV
g is the acceleration due to gravity constant (9.8 m/s2) (metric)

K a LV WKH HIIHFWLYH FRHI¿FLHQW RI IULFWLRQ ZKLFK KDV QR XQLWV
Wc is the weight correction factor which has no units

7KH EDVLF FRHI¿FLHQW RI IULFWLRQ W\SLFDOO\ UDQJHV IURP IRU SURSHUO\ OXEULFDWHG FDEOHV SXOOHG LQWR VPRRWK
clean conduits) to 0.5 (for lubricated cables pulled into rough or dirty conduits). Other factors such as jacket
PDWHULDO FRQGXLW PDWHULDO DPELHQW WHPSHUDWXUH VWUDQGLQJ ÀH[LELOLW\ RI WKH FRQGXFWRU HWF PD\ LQÀXHQFH
WKH DFWXDO IULFWLRQ IDFWRU H[SHULHQFHG 7KH XVH RI D GLIIHUHQW FRHI¿FLHQW RI IULFWLRQ PD\ EH VXEVWDQWLDWHG E\
FRPSDULVRQ RI WKH DFWXDO SXOOLQJ WHQVLRQ YHUVXV FDOFXODWHG SXOOLQJ WHQVLRQ )RU PRUH LQIRUPDWLRQ RQ FRHI¿FLHQW
of friction consult Fee [B43], Fee and Quist [B44], Weitz [B93], and IEEE Std 1210™.

Expected pulling tension of a cable in an inclined section of conduit or duct may be calculated from

Equation (6). This formula does not consider slope, or the weight correction factor. If weight correction factor
(see 4.13) is applicable replace K0 by K a , where K ′ = K0 ×Wc .

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Upward T = W × g ×L×(K0 cosα + sinα )+Tp (metric)
T = W ×L×(K0 cosα + sinα )+Tp (English) (6a)

Downward T = W × g ×L×(K0 cosα −sinα )+Tp (metric)
T = W ×L×(K0 cosα −sinα )+Tp (6b)

(English)

where: α is the the angle in degrees of the inclined section of conduit from horizontal
g is the acceleration constant due to gravity (9.8 m/s2)
Tp is the prior tension

NOTE—The acceleration of gravity constant appears in the metric equation because W in metric is mass per unit length
number whereas in the English equation W is a force (lbs) per unit length.

For conduit or duct runs containing horizontal bends, the expected pulling tension around a bend can be
determined by Equation (7) assuming the pull from A to D as shown in Figure 12(a). This formula does not
consider prior tension, or the weight correction factor. If weight correction factor (see 4.13) is applicable,
replace K0 by K ¢ , where K ′ = K0 ×Wc .

TC = TB eK0 σ (7)

where:

TC is the tension out of the bend N (lbf)
TB is the tension into the bend N (lbf)
e is the natural logarithm base (approximately 2.72)
K0 is the basic coefficient of friction which has no units
σ is the angle of bend (radians) where 1° = 0.01745 rad
R is the radius of bend m (ft) [used in Equation (8) through Equation (12)]

Figure 12—(a) Expected pulling tension around bends for conduit or duct runs containing
horizontal bends (b) concave bend (c) convex bend

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More accurate formulae for horizontal bends are shown in Equation (8) through Equation (12) shown below.11

TC = TB ×cosh (K0 ×σ )+ sinh(K0 ×σ )× TB2 +(K0 ×W × g ×R)2  (metric)
TC = TB ×cosh (K0 ×σ )+ sinh(K0 ×σ )× TB2 +(K0 ×W ×R)2  (8)

(English)

The following formulae should be used for vertical bends. Four sets are provided depending on whether the

pull is up or down and whether the bend is concave or convex.

Convex Bend, Upward Pull:

 (W ×g× R )

1+ K02
( )( )TC  
( )( ( ) ) ( )TC
= TB ×eK0 σ + × 2× K × e K0 σ ×sin(σ )+ 1− K 2 1− eK0 σ ×cos(σ ) (metric)
= TB ×eK0 σ 0 (9)
0
(English)
+  (W ×R)  ×  2× K × e K0 σ ×sin(σ )+ 1− K 2 1− eK0 σ ×cos(σ ) 
0
1+ K02 0

Concave Bend, Upward Pull:

TC = TB ×eK0 σ −  (W × g× R) ) ×  2× K0 ×sin (σ )−(1− K 2 )(eK0 σ − cos (σ )) (metric)
TC = TB ×eK0 σ 0 (10)
(1+ K02
(English)
−  (W ×R )) ×  2× K0 ×sin (σ )−(1− K 2 )(eK0 σ − cos (σ ))
0
(1+ K02

Convex Bend, Downward Pull:

TC = TB ×eK0 σ +  (W ×g× R) ) ×  2× K0 ×sin (σ )−(1− K 2 )(eK0 σ − cos (σ )) (metric)
TC = TB ×eK0 σ 0 (11)
(1+ K02
(English)
+  ((1W+×KR02)) ×  2× K 0 ×sin (σ )−(1− K 2 )(eK0 σ − cos (σ ))
0

Concave Bend, Downward Pull:

 (W × g× R )

1+ K02
( )( )TC
( )( ( ) ) ( )TC
= TB ×eK0 σ − ×  2× e K0 σ ×sin(σ )+ 1− K 2 1− eK0 σ ×cos(σ )  (metric)
0 (12)

= TB ×eK0 σ −  (W ×R)  ×  2× e K0 σ ×sin(σ )+ 1− K 2 1− eK0 σ ×cos(σ )  (English)
0
1+ K02

TB is determined for the pull by the straight-length method previously given. Equation (8) through

Equation (12) do not consider prior tension or the weight correction factor. If weight correction factor (see
4.13) is applicable, replace K0 by K ¢ , where K ′ = K0 ×Wc .

4.12 Cable configurations and cable jamming

When three single conductor cables are pulled into a duct or conduit, the conductors can assume various
configurations depending on the ratio of conduit/duct inner diameter to a single cable’s outer diameter.
However, the most common configurations are cradle and triangular as shown in Figure 13.

11Equation (8) through Equation (12) are used with permission of General Cable Technologies Corporation, all rights reserved.

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Cable configuration figure is courtesy of The Okonite Company
Figure 13—Cable configuration for three cables in conduit or duct

Cable jamming is the wedging of three single conductor cables in a conduit or duct. This occurs when the
center cable is forced between two outer cables causing the cables to line up across the conduit or duct inside
diameter (ID) and seize or jam in the conduit or duct. Serious cable damage will occur if the pull continues.
While jamming is possible to occur when pulling four or more single conductors or cables in a conduit or duct,
the probability is low. Jamming has a tendency to occur more often at the bend of a conduit or duct due to the
flattening at the bend (non-roundness) of the conduit or duct at the bend point.

The jam ratio is defined as the conduit or duct ID divided by the single cable OD and is expressed by the
formula shown in Equation (13). To allow for tolerances in cable and conduit sizes, and for non-circularity or
oval shape in the conduit at the bend, the D/d ratio (critical jam ratio) between 2.8 and 3.2 should be avoided
(see Figure 13). To avoid this condition, the jam ratio should be calculated prior to specifying the conduit size
(ID) for a cable installation, as the cable size (OD) is specified based on the required cable performance of the
circuit. The range of critical jam ratios is illustrated in Figure 13.

Jam Ratio (JR) = Conduit ID Cable OD , or (13)

JR = D d

For cases that have fewer than three single conductor cables, a single multi-conductor cable with an overall
jacket, or for cables triplexed by a cable manufacturer, cable jamming is not possible. Cable jamming is not
applicable to cable(s) pulled into trays, trenches, or troughs.

4.13 Weight correction factor

When more than one cable is pulled into a conduit or duct, the pulling tension is not a multiple of a single cable
pull. Because of the wedging action between cables and conduit/duct, even in a straight pull, the effect is to

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produce a sidewall pressure, which is treated as an increase in the basic coefficient of friction ( K0 ) and is
called the weight correction factor (Wc ). The effective coefficient of friction, K a , is shown in Equation (14).

K ′ = Wc ×K0 (14)

The pulling tension for straight pulls and “n” cables is shown in Equation (15). (15)

T = n×K ′×L×W × g (metric)
T = n×K ′×L×W (English)

The additional tension imposed by a bend is calculated the same way as for a one-cable pull except that K0 is
replaced by K a in Equation (7) or in Equation (8).

The weight correction factor (Wc ) for single conductor cable, multiple conductor jacketed cable, or triplex
construction cable in a conduit/duct is unity. The Wc for two conductors in a cable pull is typically determined
E\ XWLOL]LQJ WKH IRUPXOD IRU WKUHH FDEOHV LQ D WULDQJXODU FRQ¿JXUDWLRQ ZKLFK LV VKRZQ EHORZ

For the case of three cables, Figure 13 can be used to determine Wc when the ratio of the conduit/duct ID and
single cable OD ( D / d ) is known. For D / d UDWLRV DERYH FDEOHV WHQG WR IRUP D FUDGOH FRQ¿JXUDWLRQ 7KH
Wc for this arrangement may be calculated using Equation (16):

Wc =1+ 4 ⎣⎢⎢⎡ d ⎥⎦⎥⎤ 2 (16)
3 D−d

where:

Wc is the weight correction factor
D is the ID of the conduit/duct, mm (in)
d is the OD of the cable, mm (in)

For a D / d UDWLR XS WR FDEOHV DUH FRQVWUDLQHG LQ D WULDQJXODU FRQ¿JXUDWLRQ 7KH Wc for this arrangement
may be calculated using Equation (17).

Wc = 1 (17)

⎢⎢⎣⎡ d ⎤⎥⎥⎦ 2
−
1− D d

Cables, with a D / d ratio between 2.5 and 3.0, may assume either arrangement. Calculations should utilize a

value of Wc EDVHG RQ WKH FUDGOHG FRQ¿JXUDWLRQ

)RXU FDEOHV SXOOHG LQWR D FRQGXLW RU GXFW ZLOO DVVXPH D GLDPRQG FRQ¿JXUDWLRQ 7KH Wc for this arrangement
may be calculated using Equation (18).

Wc =1+ 2 ⎣⎢⎢⎡ D d ⎤⎥⎥⎦ 2 (18)
−d

When more than four cables are being pulled together or when multiple cables of differing sizes are being
pulled together, a Wc of 1.4 may be assumed.

(YHQ WKRXJK WKH 1(& DOORZV D FRQGXLW ¿OO UDWLR IRU WKUHH FDEOHV LQ D VLQJOH FRQGXLW FDXWLRQ VKRXOG
EH REVHUYHG ZKHQ DSSURDFKLQJ WKLV ¿OO OLPLW DV SUDFWLFDO H[SHULHQFH GHPRQVWUDWHV WKDW DV WKH ¿OO UDWLR LV
approached, the probability of cable jamming increases as well as the likelihood of cable damage during the
pull.

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4.14 Maximum allowable sidewall pressure

Sidewall pressure is the radial force exerted on the insulation and sheath of a cable at a bend point when
the cable is under tension (see Figure 14). For single conductor, multiple conductor, or triplexed power and
multi-conductor control or power cables, the maximum allowable sidewall pressure ranges from 4380 N/m
(300 lbf/ft) of radius to 7300 N/m (500 lbf/ft) of radius depending on the cable materials. For instrumentation
cable the maximum allowable sidewall pressure ranges from 4380 N/m (300 lbf/ft) to 7300 N/m (500 lbf/ft)
of radius depending on cable materials and construction. Table 7 provides typical guidelines for maximum
sidewall pressure values for various cable types. For armored cable the maximum allowable sidewall pressure
is typically 4380 N/m (300 lbf/ft) of radius or lower. Always follow the manufacturers’ recommendations
regarding maximum allowable sidewall pressure because insulation and jacketing materials and cable
configurations factor into the maximum allowable sidewall pressure values.

Courtesy of RSCC Wire and Cable from the RSCC Storage and Instruction Manual [B63]
Figure 14—Example of measuring sidewall pressure

Table 7—Guidelines for maximum sidewall pressure values for various cable types

Cable type Maximum sidewall pressure
N/m lbf/ft

600 V multi-conductor (non-shielded) 7300 500

600 V and 1 kV single conductor ——

Size 8 and smaller 4380 300

Size 6 and larger 7300 500

5 to 15 kV power cable (shielded) 7300 500

25 to 35 kV power cable (shielded) 4380 300

Interlocked armored cable (all voltage classes) 4380 300

Instrumentation cable – single pair (shielded) 4380 300

Instrumentation cable – multi-pair (shielded) 7300 500

NOTE—These are general guidelines concerning maximum sidewall pressure. If different,
manufacturer’s guidelines take precedence over these guidelines. Reference IEEE Std 576
[B67].

A typical SWBP limit for armored cables is 4380 N/m (300 lbf/ft) of bend radius. Because SWBP limits can
vary based on the type of cable armor employed, it is recommended to consult with the cable manufacturer to
determine the maximum allowable SWBP for armored configurations.

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4.15 Expected SWBP
The expected SWBP acting upon a cable at any bend may be estimated as follows:

— For single cable or one cable [Equation (19)]
— For three cables in cradle formation where center cable presses hardest [Equation (20)]
— For three cables in triangular formation where pressure is divided equally between two bottom cables

[Equation (21)]
P = T (19)

Rb

P = 1 (3Wc − 2) T (20)
3
Rb

P = Wc ×T (21)
2Rb

where:
P is the SWBP on the cable(s) in N/m (lbf/ft)
T is the total pulling tension in N (lbf)
Rb is the radius of bend in m (ft)
Wc is the weight correction factor

The cable manufacturer’s recommendations should be followed for all cable configurations not covered by the
equations in this clause.

5. Accessories required for the pull

There are several types of pulling attachments commonly referred to as pulling eyes or pulling grips, which are
available for connection to the cable. Upon request, most cable manufacturers will supply pulling eyes on the
ends of large power cable. Basket-type pulling grips, compression-type pulling eyes, wedge-type pulling eyes,
mare’s tails, and other types of accessories are also used during cable pulling.

5.1 Rope and tapes

5.1.1 General

A variety of constructions and materials are available for use in pulling cables through conduits and trays.
Common materials include natural and synthetic fibers and steel tapes. Rope/tape performance is also
considerably influenced by its construction. See ARNCO’s Bull-Line Pull Tape Guide [B27] for more
information on tape bull lines. Common materials are as follows:

— Natural fibers: Inexpensive rope made from natural vegetable fibers including manila, sisal, and
cotton. The main disadvantage of natural fibers is that they are subject to rot and mildew in wet or
damp environments.

— Polyester: Strong, synthetic rope/tape with excellent abrasion resistance; lower stretch, and elasticity;
and higher loading characteristics than nylon ropes/tapes. Available in many specially designed
finishes (including pre-lubricated woven polyester tapes) for improving handling and longer life.

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— Aramid: These ropes/tapes have been engineered for applications where low weight, high strength,
good abrasion resistance, and excellent bending capability are important to a successful pull.

— Nylon: First synthetic fiber rope/tape to be made and still a popular choice due to its low cost. It has
a high elasticity modulus, which allows a nylon rope to absorb sudden shock loads that would break
other rope types. It has good resistance to abrasion and typically lasts five times longer than natural
fiber ropes. It is rot-proof and not damaged by oils, gasoline, grease, marine growth, and most non-acid
chemicals.

— Polypropylene: A lightweight, strong rope/tape and used most of any ropes/tapes. It is rot-proof and
unaffected by water, oils, gasoline, and most chemicals. It is available in monofilament (smooth
surface) fibers or multifilament (velvety appearance and touch) fibers. Newer polypropylene ropes/
tapes are available with greater strengths and higher abrasion resistance characteristics.

— Steel: 3.2 mm (1/8 in) and 6.4 mm (1/4 in) tape width steel tapes have maximum design strength of
1700 N (400 lbf).

5.1.2 Guidelines for pull rope and tape selection

Pull rope constructions include single and multi-stranded, plaited, single-braid, double braid, and parallel
core. Selection of a pulling rope should be based on required pulling tension, lubricant compatibility, rope
size, rope flexibility, and rope abrasion characteristics and the degree of expected rope stretch under tension.
When selecting a pull rope, consideration should also be given to conduit material, expected cable pulling
tension, and the application, as well as the cost. The best choice is one with high tensile strength and low
stretch characteristics, such as a double-braided composite rope. Choose a rope that has the capacity to handle
four times the capacity of the tugger/puller being used, but no less than 1.5 times the expected pulling tension.
Table 8 and Table 9 summarize the different rope characteristics that should be considered for rope selection.

Table 8—Pull rope/tape characteristics

Rope characteristic Characteristics important to pull rope applications

Working load rating Pulling tension should not exceed the rope’s/tape’s working load rating.

Abrasion characteristic In a pullby or when pulling cable through plastic conduit, the pull
rope/tape should not abrade the existing cables or conduit.

Suitability in wet area Pulls through underground ducts are generally considered wet. Hemp
(natural fiber, cotton, sisal, manila) rope/tape will rot if not properly dried
out after the pull.

Compatibility with lubricants Some lubricants can degrade the life of the pull rope/tape.

Energy absorption capability If a rope/tape breaks during the pull, ropes/tapes with higher energy
absorption capability present a greater personnel hazard.

Sunlight resistance During pulls in outdoor areas, the pull rope/tape may sometimes be left
in the sun for extended periods of time.

Percentage of elongation or stretch In high-tension pulling applications, excessive stretching of the rope/tape
is a major contributor to galloping and to personnel hazard if the rope/tape
breaks.

Heat sink properties In high-tension pulling applications, rope/tape friction against the conduit
can produce a substantial amount of heat. If the rope/tape cannot dissipate
the heat and the coefficient is high, plastic conduit could soften and melt.

Courtesy of US. Rope and Cable; Source: www.us-rope-cable.com

WARNING
Personnel should never stand in line with rope under tension. If a rope breaks, it can recoil with lethal force

45

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IEEE Std 1185-2019Table 9—Rope and tape ¿ber selection guide (typical characteristics)
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities
Fiber type Composite Twisted yellow Woven polyester Spiral wrapped light Manila rope Solid braid Three-strand
46 double-braid rope nylon rope polypropylene rope
Diameter range (polyester outer polypropylene rope tape duty poly twine
Copyright © 2020 IEEE. All rights reserved.[mm (in)]jacket and nylon 6.4 to 51.0
Authorized licensed use limited to: Ubon Ratchathani University. Downloaded on January 07,2022 at 02:55:43 UTC from IEEE Xplore. Restrictions apply.Tensile strength4.8 to 9.512.7 to 19.0n/a6.4 to 76.03.2 to 12.7(1/4 to 2)
range inner core) (3/16 to 3/8) (1/2 to 3/4) (1/4 to 3) (1.8 to 1/2)
[N (lbf)]
Characterization 9.5 to 25.4
(3/8 to 1)
Application
22 250 to 186 900 3200 to 10 860 5560 to 26 700 935 2400 to 256 320 2540 to 23 500 5560 to 2 314 000
(5000 to 42 000) (720 to 2440) (1250 to 6000) (210) (540 to 57 600) (570 to 5300) (1250 to 52 000)

ʊHigh strength, ʊLightweight ʊHigh tensile ʊWill not rot or ʊHolds knots well ʊGood UV ʊEconomical
low stretch ʊEconomical strength, low stretch mildew ʊLow stretch resistance ʊVery light
ʊExcellent UV, ʊHigh chemical ʊEasily blown ʊCan be left ʊabsorbs water ʊExcellent rot and ʊLow stretch
chemical, and resistance through conduits in conduit for ʊPoor resistance to mildew resistance ʊHigh chemical
abrasion resistance ʊEasily spliced and ducts future use rot and mildew ʊVery good resistance
ʊGood UV abrasion resistance
Heavy-duty cable Cable pulling line Cable pulling tape Cable pulling twine resistance General
pulling line Blocks, pulleys, purpose rope
General winches, and
purpose rope general tie-downs

Courtesy of US Rope and Cable (www.us-rope-cable.com)

IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

Use of steel tapes or ropes should be avoided for plastic conduit because testing has shown that steel pull ropes
can wear grooves in plastic conduit elbows. The cables being pulled may then be damaged by these grooves.
It is recommended that rigid metal conduit (steel) or FRPE (fiberglass) elbows should be used to help prevent
this.

Synthetic ropes are used on long pulls with a capstan on a winch truck or self-powered winches. They are also
used for manual pulling of short runs, for removing old cable, and for pullbys into conduit.

Pull ropes are rated in terms of maximum and minimum breaking strength, working load, percentage of
elongation versus load, and stored energy. The ratio of maximum breaking strength to working load ranges
from 4:1 to 7:1 with rope material and construction.

The rope working load rating should not be exceeded. However, transient tensions 10% above the working
load rating are generally permitted. In order to provide a margin of safety and account for rope aging, the
working load rating of the rope should be four times the tugger/puller capacity but no less than 1.5 times the
projected cable pulling tension.

5.1.3 Precautions
Pull ropes should be checked prior to each pull for signs of aging or wear, including frayed strands and broken
yarns. A heavily used rope will often become compacted or hard, indicating reduced strength. If there is any
question regarding the rope’s condition, it should not be used. Because visual inspection cannot accurately and
precisely determine residual rope strength, it is prudent to replace the rope when any indications of wear or
aging are evident.

Rope should be stored in a clean dry place, out of direct sunlight, and away from heat sources. Some synthetic
ropes, particularly polypropylene and aramid fiber ropes may weaken by prolonged exposure to UV rays.

Improper pull rope selections can damage the conduits or cause galloping to occur during the pull. In high-
tension pulls, stretching the pull rope may occur and the cables themselves may stop moving. To start the
cable moving again the pulling tension increases dramatically and the cable tends to jump forward in the
process. This is called galloping and is to be avoided as it generates unexpectedly high tension. Ropes with
low elasticity at the expected pulling tension should be used.

5.2 Swivels and sheaves
5.2.1 Swivels
Swivels (Figure 15) are used between the pull rope and the grip devices to help prevent cables from twisting
during the pull. Swivels are recommended for use in high-tension pulling applications. Two common types of
swivels are the space swivel and the ball-bearing swivel. Swivels should be selected that will turn under the
anticipated load conditions. Swivels that do not revolve under high load conditions should never be used.

courtesy of Anixter, Canada

Figure 15—Swivel

47

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

Care should be exercised to avoid rapid changes in tension because swivels have been known to fail in an
explosive-like manner under extreme conditions of rapid tension changes. This can occur even with ball-
bearing swivels.
5.2.2 Conveyor sheaves
Damage may occur to cable while being installed in tray or into a conduit if the maximum sidewall pressures
are exceeded. Sidewall pressure, force per unit length of radius, is exerted on a cable when it is pulled around a
sheave. Where a change in the direction of the cable pull is made, conveyor sheaves should be used. Conveyor
sheaves are multi-sheave devices bound together by a rigid metal frame to form an arc of various degrees. Due
to the small diameter of individual sheaves, it is recommended that each conveyor sheave have a minimum of
one sheave for every 20° of bend as shown in Figure 16. Figure 17 shows that a three-wheeled pulley requires
less physical space than a single-wheeled pulley for the same 90° bend.

Figure 16—Conveyor sheave arrangement

Figure 17—Three-wheeled pulley

Conveyor sheaves should be properly sized with radii sufficiently large to satisfy the maximum allowable
sidewall pressure limits and minimum bending radii requirements. Alignment of the conveyor sheaves to
accept the cable should be made prior to the actual pull, by applying tension to the pulling rope and aligning
the rope in the center of the sheaves. Slight adjustments during the pull may be required. The sheaves and the
individual sheaves of conveyor sheaves should be free turning and well lubricated.
Because the sheaves are assumed to be frictionless, the tension out of the sheave is considered to be the same
as the tension into the sheave. However, the cable generates a moment of force in its effort to conform to the

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IEEE Std 1185-2019
IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

shape of the sheaves. From practical experience, this force or tension is typically between 445 N to 667 N (100
lbf to 150 lbf) for single conductor copper cables 500 kcmil or larger or for single conductor aluminum cables
750 kcmil or larger. This force should be added to the total tension calculations. By using Equation (19), the
calculation of the SWBP coming out of a sheave can be determined as shown in Equation (22), as follows:

P = T Rs (22)

where:

P is the SWBP, N/m (lbf/ft)
T is the tension out of sheave, N (lbf)
Rs is the radius of sheave, m (ft)

By placing a sheet of plywood or some other rigid, flat-surfaced material over the tray at a bend, the sheave
can be placed on top of the plywood and over the existing cable. This flat-surfaced material not only protects
the existing cable but provides support to the sheave. Any rollers or sheaves with sharp edges or protrusions
should be repaired or replaced prior to beginning the pull.

The cable itself should be lubricated by swabbing the surface as it comes off the reel in addition to lubricating
the bearings on rollers and sheaves. The lubricants should be compatible with the cable jacket.

5.3 Rollers

5.3.1 Roller spacing and mounting for cable tray installation

Spacing of the rollers should be adequate to help prevent the moving cable from touching or rubbing
against the cable tray. The rollers should be placed to keep the cable in a fairly level position. The tension is
significantly greater as the cable approaches the end of the pull allowing for more distance between rollers.
Field experience shows that normally rollers should be spaced between 3 m to 5 m (10 ft to 15 ft) apart. The
objective is to reduce drag and tension. Equation (23) can be used to calculate the approximate roller spacing
intervals, as follows:

S= 8×H ×T (metric)
W ×g
(23)
S = 8×H ×T (English)
W

where:

S is the distance between rollers, m (metric), ft (English)
H is the height of top of rollers above tray surface, m (metric), ft (English)
T is the tension, N (metric), lbf (English)
W is the weight per unit length of cable, kg/m (metric), lbf/ft (English)
g is the acceleration due to gravity constant (9.8 m/s2)

Use of this equation requires an estimate of tensions along the cable tray route. Field experience has shown
that it is not practical to use different roller spacing in the same pull. The installer should have as many rollers
as necessary in place to help prevent excess sag and drag. Often an installation requires that the sheave/roller
apparatus be attached and suspended. The support structure should have adequate mechanical strength to
handle the tensions applied to the cable when making the pull. Cable tray systems are not usually designed to
be the support structure for sheaves or rollers (see Figure 18).

49

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IEEE Recommended Practice forCable Installation in GeneratingStations and Industrial Facilities

IEEE Recommended Practice for Cable Installation in Generating Stations and Industrial Facilities

IEEE Recommended Practice forCable Installation in GeneratingStations and Industrial Facilities

Keywords: IEEE Power and Energy Society,IEEE Std 1185™-2019 (Revision of IEEE Std 1185-2010)

IEEE Recommended Practice for
Cable Installation in Generating
Stations and Industrial Facilities

IEEE Recommended Practice for
Cable Installation in Generating
Stations and Industrial Facilities