IEC TR 61328:2017

Live working - Guidelines for the installation of transmission and distribution line conductors and earth wires - Stringing equipment and accessory items

IEC TR 61328:2017(E) provides recommendations for the selection and testing where necessary of conductor stringing equipment and accessory items used for the installation of bare and insulated overhead distribution conductors, bare overhead transmission conductors and overhead earth wires. This third edition cancels and replaces the second edition published in 2003 and IEC TR 61911:2003. It incorporates some technical changes to update equipment work methods and procedures, bringing them in line with the state of the art.

General Information

• Status: Published
• Publication Date: 09-Apr-2017
• ICS: 13.260 - Protection against electric shock. Live working
• ICS: 29.240.20 - Power transmission and distribution lines
• ICS: 29.260.99 - Other electrical equipment for working in special conditions
• Technical Committee: TC 78 - Live working
• Current Stage: PPUB - Publication issued
• Start Date: 10-Apr-2017
• Completion Date: 10-Apr-2017

Standards Content (sample)

IEC TR 61328
Edition 3.0 2017-04
TECHNICAL
REPORT
colour
inside
Live working – Guidelines for the installation of transmission and distribution
line conductors and earth wires – Stringing equipment and accessory items
IEC TR 61328:2017-04(en)
---------------------- Page: 1 ----------------------
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IEC TR 61328
Edition 3.0 2017-04
TECHNICAL
REPORT
colour
inside
Live working – Guidelines for the installation of transmission and distribution
line conductors and earth wires – Stringing equipment and accessory items
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.260; 29.240.20; 29.260.99 ISBN 978-2-8322-4130-1

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TR 61328:2017 © IEC 2017
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Understanding the hazard – Basic theory ...................................................................... 17

4.1 General ................................................................................................................. 17

4.2 Electric field induction from nearby circuits ........................................................... 17

4.2.1 Overview ..................................................................................................... 17

4.2.2 Induced voltage ........................................................................................... 18

4.2.3 Induced current ............................................................................................ 19

4.2.4 Electrostatic charging .................................................................................. 20

4.3 Magnetic field induction from nearby circuits ......................................................... 20

4.3.1 Induced current ............................................................................................ 20

4.3.2 Induced voltage ........................................................................................... 21

4.4 Re-energization .................................................................................................... 22

4.5 Mechanical risk ..................................................................................................... 22

5 Conductor stringing methods and equipment ................................................................. 23

5.1 General ................................................................................................................. 23

5.2 Slack stringing method .......................................................................................... 23

5.3 Tension stringing method ...................................................................................... 25

5.4 Stringing equipment .............................................................................................. 34

5.4.1 General........................................................................................................ 34

5.4.2 Tensioners ................................................................................................... 34

5.4.3 Pullers ......................................................................................................... 37

5.4.4 Reel winders ................................................................................................ 41

5.4.5 Reel stands ................................................................................................. 42

5.4.6 Pilot rope puller ........................................................................................... 43

5.4.7 Pilot rope, pulling rope ................................................................................. 43

5.4.8 Woven wire grip ........................................................................................... 44

5.4.9 Stringing blocks ........................................................................................... 44

5.4.10 Stringing rollers ........................................................................................... 47

5.4.11 Stringing block earth .................................................................................... 48

5.4.12 Running earth .............................................................................................. 49

5.4.13 Hold-down block .......................................................................................... 49

5.4.14 Conductor car .............................................................................................. 49

5.5 Communications ................................................................................................... 53

6 Special earthing requirements ....................................................................................... 53

6.1 General ................................................................................................................. 53

6.2 Work site earthing systems ................................................................................... 54

6.2.1 Overview ..................................................................................................... 54

6.2.2 Use of earth rods ......................................................................................... 55

6.2.3 Equipment earths ......................................................................................... 56

6.2.4 Earths for conductor, earth wire, metallic and synthetic rope ........................ 56

6.2.5 Earths for earth mat, conductors or earth wires ............................................ 56

6.2.6 Earths for mid-span joining of conductors or earth wires .............................. 56

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IEC TR 61328:2017 © IEC 2017 – 3 –

6.2.7 Earths for clipping in the conductors or earth wires ...................................... 57

6.2.8 Earths for installation of jumper loops for the conductor ............................... 57

6.2.9 Stringing block earths .................................................................................. 57

6.2.10 Earth mat ..................................................................................................... 57

6.3 General procedures and use of earthing systems .................................................. 62

6.3.1 Overview ..................................................................................................... 62

6.3.2 General procedures ..................................................................................... 62

6.3.3 Installation of the pilot or pulling rope .......................................................... 63

6.3.4 Stringing of conductors ................................................................................ 64

6.3.5 Splicing of conductors .................................................................................. 65

6.3.6 Sagging of conductors ................................................................................. 66

6.3.7 Clipping-in conductors ................................................................................. 67

6.3.8 Dead-ending and installation of jumper loops ............................................... 67

6.3.9 Spacing ....................................................................................................... 68

6.3.10 Special work on conductors ......................................................................... 68

6.3.11 Fuelling ........................................................................................................ 69

7 Testing of earthing devices ............................................................................................ 69

7.1 General ................................................................................................................. 69

7.2 Number of type tests ............................................................................................. 70

7.3 Type test set-up .................................................................................................... 70

7.4 Type test acceptance criterion .............................................................................. 70

Bibliography .......................................................................................................................... 73

Figure 1 – Electric field induction from nearby circuits – Induced voltage .............................. 18

Figure 2 – Electric field induction from nearby circuits – Induced current .............................. 19

Figure 3 – Magnetic field induction from nearby circuits – Induced current ............................ 21

Figure 4 – Magnetic field induction from nearby circuits – Induced voltage ........................... 22

Figure 5 – Slack stringing method ......................................................................................... 25

Figure 6 – Tension stringing method ..................................................................................... 33

Figure 7 – Bullwheel tensioners ............................................................................................ 37

Figure 8 – Bullwheel pullers .................................................................................................. 41

Figure 9 – Stringing blocks ................................................................................................... 47

Figure 10 – Stringing rollers .................................................................................................. 48

Figure 11 – Conductor cars ................................................................................................... 50

Figure 12 – Earthing systems ................................................................................................ 62

Figure 13 – Typical test set-up for stringing block earth ........................................................ 71

Figure 14 – Typical test set-up for running earth ................................................................... 72

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– 4 – IEC TR 61328:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIVE WORKING – GUIDELINES FOR THE INSTALLATION
OF TRANSMISSION AND DISTRIBUTION LINE CONDUCTORS AND
EARTH WIRES – STRINGING EQUIPMENT AND ACCESSORY ITEMS
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

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The main task of IEC technical committees is to prepare International Standards. However, a

technical committee may propose the publication of a Technical Report when it has collected

data of a different kind from that which is normally published as an International Standard, for

example "state of the art".

IEC TR 61328, which is a Technical Report, has been prepared by IEC technical committee

78: Live working.
This third edition cancels and replaces the second edition published in 2003 and

IEC TR 61911:2003. It incorporates some technical changes to update equipment work

methods and procedures, bringing them in line with the state of the art.
The text of this Technical Report is based on the following documents:
Enquiry draft Report on voting
78/1145/DTR 78/1174/RVDTR
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IEC TR 61328:2017 © IEC 2017 – 5 –

Full information on the voting for the approval of this Technical Report can be found in the

report on voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

Terms defined in Clause 3 are given in italic print throughout this standard.

The committee has decided that the contents of this publication will remain unchanged until

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related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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colour printer.
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– 6 – IEC TR 61328:2017 © IEC 2017
INTRODUCTION

With the increased difficulty of de-energizing existing overhead lines, installing conductors or

earth wire in circuits nearby, or crossing these existing circuits, creates hazards requiring

special considerations particularly with regard to earthing and bonding. It is also important to

provide protections against induced static charge due to atmospheric conditions, lightning

strikes, or accidental energization.

These potential electrical hazards demand that certain requirements be observed when

choosing equipment and work methods for the protection of personnel or equipment.

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IEC TR 61328:2017 © IEC 2017 – 7 –
LIVE WORKING – GUIDELINES FOR THE INSTALLATION
OF TRANSMISSION AND DISTRIBUTION LINE CONDUCTORS AND
EARTH WIRES – STRINGING EQUIPMENT AND ACCESSORY ITEMS
1 Scope

This document, which is a Technical Report, provides recommendations for the selection and

testing where necessary of conductor stringing equipment and accessory items used for the

installation of bare and insulated overhead distribution conductors, bare overhead

transmission conductors and overhead earth wires.

Procedures are recommended for proper earthing in order to protect equipment, components

and personnel from currents which can result from accidental contact with nearby energized

conductors or from the induced or fault currents which can result in some circumstances.

The items of equipment under consideration in this document are used for transmission and

distribution systems.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements of this document. For dated references, only the edition

cited applies. For undated references, the latest edition of the referenced document (including

any amendments) applies.

IEC 60050-466, International Electrotechnical Vocabulary – Chapter 466: Overhead lines

(available at www.electropedia.org)

IEC 60050-651, International Electrotechnical Vocabulary – Part 651: Live working

(available at www.electropedia.org)
IEC 60743, Live working – Terminology for tools, devices and equipment
3 Terms and definitions

NOTE Terminology for equipment and procedures associated with the installation of overhead conductors and

earth wires varies widely throughout the utility industry.

For the purposes of this document, the terms and definitions given in IEC 60050-466,

IEC 60050-651, IEC 60743 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
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– 8 – IEC TR 61328:2017 © IEC 2017
3.1
anchor
anchor log
deadman
sledge
snub
device that serves as a reliable support to hold an object firmly in place
3.2
basket
bucket

device designed to be attached to the boom tip of a line truck, crane or aerial lift to support

workmen in an elevated working position
3.3
birdcaging
opening up of the outer layers of a conductor to form a bulge in the conductor
3.4
block
tackle
pulley

device designed with one or more sheaves, a synthetic plastic or metal shell, and an

attachment hook or shackle
3.5
bond
equipotential connection
connection

electrical connection used to bring all personnel and objects in the work area to the same

potential
3.6
bullwheel

wheel or wheels incorporated as an integral part of a puller or tensioner with multiple offset

grooves allowing the continuous winding of a conductor or a rope to generate pulling or

braking tension, through friction
3.7
circuit

conductor or system of conductors through which an electric current is

intended to flow

Note 1 to entry: In transmission and distribution lines, a circuit usually consists of three phases for AC lines, and

two poles for DC lines.
[SOURCE: IEC 60050-466:1990, 466-01-07]
3.8
clearance

minimum separation between two conductors operating at different voltages, between

conductors and supports or other objects, or between conductors and the earth
3.9
clipping-in
clamping-in
clipping

transferring of sagged conductors from the stringing blocks to their permanent suspension

positions and the installing of the permanent suspension clamps
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IEC TR 61328:2017 © IEC 2017 – 9 –
3.10
compression joint
conductor splice
sleeve
splice

tubular compression (or implosive) sleeves designed and fabricated from aluminium, copper

or steel compressed to join or terminate conductors or overhead earth wires
3.11
conductor
cable
wire

bare or insulated wire or combination of wires, suitable for carrying an electric current

3.12
conductor bundle

set of individual conductors connected in parallel and disposed in a uniform geometrical

configuration, that constitutes one phase or pole of a line
[SOURCE: IEC 60050-466:1990, 466-10-20]
3.13
conductor car
cable buggy
cable car
conductor trolley
line car
spacer buggy
spacing bicycle
spacer cart

device designed to carry workmen riding on sagged single or bundle conductors, enabling

them to inspect the conductors for damage or install spacers, dampers or other attachments

3.14
conductor cover
line hose
line guard

flexible or rigid protective cover used to shroud the conductor providing electrical protection

3.15
conductor clamp
chicago grip
conductor grip
come-along
come-along clamp

preformed, bolted or wedge-type device designed to permit the pulling or temporary holding of

the conductor or of the rope without splicing on fittings, eyes, etc.
3.16
connector link
pulling rope connector
link
peanut
fixed joint

rigid link designed to connect pulling ropes and usually designed to pass through the grooves

of bullwheels on the puller when under load
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– 10 – IEC TR 61328:2017 © IEC 2017
3.17
cradle blocks system

system of cradle stringing blocks, spacer rope, pulling rope, a brake unit, and a radio

controlled motorized tug, which use the existing conductor as support when installing the new

conductor, to create a supporting protection in case of critical crossings
3.18
crossing structure
guard structure
H-frame
rider pole structure
scaffolding
temporary structure

structure built of poles, tubes, or other specialized equipment, sometimes using rope nets,

used whenever conductors are strung over roads, power lines, communications circuits,

highways or railroads to prevent the conductor from contacting any of these facilities in the

event of equipment failure, broken pulling ropes, loss of tension, etc.
3.19
dead
de-energized

at an electric potential equal to or not significantly different from that of the earth at the work

site
[SOURCE: IEC 60050-651:2014, 651-21-09]
3.20
dead-ending
procedure which results in the termination of conductors at an anchor structure
3.21
(local) earth
(local) ground (US)

part of the Earth which is in electric contact with an earth electrode and the electric potential

of which is not necessarily equal to zero
[SOURCE: IEC 60050-195:1998, 195-01-03]
3.22
earthing cable

flexible conductor usually of stranded copper with a transparent cable protective sheath, and

attached at both ends to clamps, designed to connect conductors or equipment to earth or to

an earth mat
3.23
earth clamp

clamp forming part of an earthing and short-circuiting device connecting an earthing cable, or

a connecting cluster to an earthing conductor, or an earth electrode or a reference potential

[SOURCE: IEC 60050-651:2014, 651-25-03]
3.24
earth mat
counterpoise
earth grid

system of interconnected bare conductors arranged in a pattern over a specified area on, or

buried below, the surface of the Earth
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IEC TR 61328:2017 © IEC 2017 – 11 –
3.25
earth rod
earth electrode
rod driven into the Earth to serve as an earthing terminal
EXAMPLE Copper-clad steel rod, solid copper rod, or galvanized steel rod.
3.26
earth wire
shield wire
skywire
static wire

conductor connected to earth at some or all supports, which is suspended usually but not

necessarily above the line conductors to provide a degree of protection against lightning

strikes
[SOURCE: IEC 60050-466:1990, 466-10-25]
3.27
earthing stick
earthing pole

insulating component equipped with a permanent or detachable end fitting for installing

clamps, short-circuiting bars or conductive extension components onto electrical installation

[SOURCE: IEC 60050-651:2014, 651-25-05]
3.28
earthing system

system consisting of all interconnected earthing connections in a specific area, such as a pull

section
3.29
electromagnetic induction
electromagnetic coupling

phenomenon that produces both an induced voltage and current either through electric or

magnetic field induction
3.30
electric field induction
capacitive coupling

process of generating voltages and/or currents in a conductive object or electrical circuit by

means of time-varying electric fields
3.31
energized
alive
current-carrying
hot
live

at a potential significantly different from that of the earth at the work site and which presents

an electrical hazard

Note 1 to entry: A part is energized when it is electrically connected to a source of electric energy. It can also be

energized when it is electrically charged under the influence of an electric or magnetic field.

[SOURCE: IEC 60050-651:2014, 651-21-08]
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– 12 – IEC TR 61328:2017 © IEC 2017
3.32
equipotential
set of points all of which have the same potential
3.33
factor of safety

ratio of ultimate strength or yield strength to the maximum allowable applied force or load

3.34
fault

physical condition that causes a device, a component, or an element to fail to perform in a

required manner
3.35
fault current
earth fault current

current flowing at a given point of a network resulting from a fault at another point of this

network
3.36
hold-down block

block designed to prevent uplift and to maintain the pilot rope or conductor(s) inside the

sheaves of the stringing block installed on the tower
3.37
isolated

disconnected completely from other devices or circuits, and thus separated

physically, electrically and mechanically from all sources of electrical energy
Note 1 to entry: Such sep
...