Conductor Stringing

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Conductor Stringing

Safe Practice Guide

ihsa.ca


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Infrastructure Health & Safety Association

Safe Practice Guide

Conductor Stringing

Foreword

This Guide designates the practices that should be

followed by the member firms of the Infrastructure

Health & Safety Association (IHSA) when involved in

conductor stringing operations. This Guide is not

designed as a training manual, but contains informa-

tion, best practices and general recommendations

deemed appropriate to perform a job in a responsibleand safe manner.

The contents of this Safe Practice Guide, including all

advice, recommendations and procedures, are

provided as a service by the Infrastructure Health &

Safety Association. No representation of any kind is

made to any persons whatsoever with regard to the

accuracy, completeness or sufficiency of the informa-

tion contained herein. Any and all use of or reliance on

this Safe Practice Guide and the information containedherein is solely and entirely at the user's risk. The user

also acknowledges that the safe practices described

herein may not satisfy all requirements of Ontario law.

The Infrastructure Health & Safety Association wishes

to express its appreciation to those who assisted in

the preparation of this Guide.

All rights reserved. This publication may not be reproduced,

in whole or in part, without the express written permission of

the copyright owner.

12/05


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TABLE OF CONTENTS

Introduction 4Purpose 4

SECTION I

GENERAL

100 Safe Execution of Work 6

101 Competent Personnel 6

102 Job Planning Tailboard Talks 6

103 Communication and Teamwork 7

104 Suitable Equipment Work Methods 7

105 Utility Work Protection Code 7

106 Work Area Protection 8

107 Protective Cover-up Devices 8

SECTION II

STRINGING PROCEDURES

200 Personal Protection 10

201 Initial Preparation 10

202 Preparation for Work 11


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SECTION III

TEMPORARY GROUNDING

AND BARRICADING OF EQUIPMENT

300 General Precautions 14

301 Procedures for Setting Up

Ground Gradient Mats 15

302 Procedure for Setting Up Stringing Equipment 17

303 Procedure for Setting Up Barriers 17

304 Procedure for Grounding/Bonding During

Stringing Operations 18

SECTION IV

CONVENTIONAL STRINGINGMETHODS

400 General 28

401 Tension Brake Devices 28

402 Pulling Devices 30

403 Miscellaneous Equipment 31

404 Removing Old Conductor 34

SECTION V

TENSION STRINGING METHODS

500 General 38

501 Miscellaneous Equipment 38

502 Pulling Ropes 39


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INTRODUCTION

Conductor stringing operations date back to the

beginning of the electric power era. However, theoriginal stringing methods used in the past no longer

provide the safe work zone required by current regula-

tory agencies and management philosophies. The

ever-increasing presence of obstacles such as

telecommunications plant, other power lines, roads,

highways and railroad right of ways have made it

necessary to use different methods of conductor

stringing in order to avoid unnecessary risk or interfer-

ence from these obstacles. More modern types of

conductor stringing equipment have been developed,

and many complex stringing jobs have been com-

pleted safely using this equipment.

PURPOSE

This Safe Practice Guide has been compiled to

familiarize utility and telecommunications personnel,

and their contractors, with various conductor stringing

methods, safe work practices, and the equipmentnecessary to undertake a stringing operation in a safe

manner.


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SECTION I

GENERAL

100 SAFE EXECUTION OF WORK

101 COMPETENT PERSONNEL

102 JOB PLANNING TAILBOARD TALKS

103 COMMUNICATION AND TEAMWORK

104 APPROPRIATE EQUIPMENT WORK METHODS

105 UTILITY WORK PROTECTION CODE

106 WORK AREA PROTECTION

107 PROTECTIVE COVER-UP DEVICES


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SECTION I

GENERAL

100 SAFE EXECUTION OF WORK

The safe execution of a conductor stringing operation

requires:

- competent personnel

- proper, detailed job planning

- approved work methods

- effective communication and teamwork

- well maintained, appropriate equipment

101 COMPETENT PERSONNEL

Only competent personnel, or personnel in training

under the direct supervision of a competent person

should engage in conductor stringing operations.

102 JOB PLANNING TAILBOARD TALKS

As in all other phases of utility and telecommunica-tions work, job planning is of the utmost importance so

that the work may be performed safely and efficiently. A

documented tailboard talk should be held with all

involved in the project prior to the commencement of

work. This includes workers at both the pulling and

tensioning ends. The details of the tailboard talk

should include all known hazards, and the barriers that

will be used to protect workers and the public. All

workers must understand the procedures and theirrespective duties and responsibilities before work

commences. Should it become necessary to change

the original job plan, all workers should be brought

together and the new plan explained thoroughly to

them.


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103 COMMUNICATION AND TEAMWORK

Effective communication is essential while the work is

being performed. Operators at the pull in and pay

out ends should be in constant communication withone another during the stringing operation. In addition,

a competent person should follow the progress of the

running board or rope/conductor connection. This

person should be in constant communication with the

puller/tensioner operators. Teamwork is essential to

ensure the safe and efficient execution of the job.

Various types of conductor stringing equipment are

currently being used. However, it is imperative that only

appropriate equipment in good repair be used for the

stringing method to be followed on each particular job.

This would apply to pulling lines, travellers, pulling

devices, tensioning, grounding methods and braking

devices, etc.

Local conditions will determine the appropriate

stringing method to be used. Before deciding on aparticular conductor stringing method, consider factors

such as the length of pull, the location of other circuits,

road crossings, etc.

105 UTILITY WORK PROTECTION CODE

During any stringing operation that is to be carried out

in proximity to existing energized apparatus, the

possibility exists that a conductor being pulled in could

inadvertently contact the energized apparatus. There-

fore, it is of the utmost importance that the person in

charge of the work obtain suitable hold-off protection

on all of the energized circuits or apparatus which

could cause a hazard to the stringing operation.

104 APPROPRIATE EQUIPMENT WORK METHODS


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Any existing isolated lines in proximity to the stringing

operation should be suitably tagged and grounded in

accordance with the Utility Work Protection Code, or

equivalent.

106 WORK AREA PROTECTION

Stringing operations may be carried out along busy

thoroughfares and, because personnel and equipment

may be situated in various locations along the route,

proper work area protection is a prerequisite for the

safe execution of the job.

Work area protection should be established in accord-ance with the current Ministry of Transportation, Ontario

(MTO), the Ontario Highway Traffic Act and local bylaws.

107 PROTECTIVE COVER-UP DEVICES

Whenever conductors are being installed or removed

near energized conductors or apparatus, an electrical

hazard is possible. The preferred course of action is to

eliminate the hazard by re-routing the feed to providefor circuit isolation. In cases where isolation is not

feasible, relocation of the conductors and appropriate

cover-up would be the next choice. In some instances,

appropriate cover-up is the only alternative. Always use

cover-up of the appropriate voltage rating. Special

attention should be given to locations where the

conductor being pulled crosses any energized appara-

tus.

NOTE: To prevent rope burns to protective cover-up

devices, ensure that the str inging rope and/or

conductor being pulled in does not drag

across the cover-up during the stringing

operation.


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SECTION II


200 PERSONAL PROTECTION

201 INITIAL PREPARATION

202 PREPARATION FOR WORK


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SECTION II


200 PERSONAL PROTECTION

During all stringing operations in proximity to energized

apparatus, all personnel should follow the ground to

ground rubber glove rule as set out in the Electrical

Utility Safety Rules (EUSR). Also, personnel working in

areas not protected by equipotential grounding and

bonding should wear rubber gloves.

201 INITIAL PREPARATION JOB PLANNING

1. Ensure that work orders, detailed drawings, jobinstruction, etc. are prepared in advance.

2. Ensure that any necessary applications for work

protection are arranged for in advance.

3. Decide on the safest and most practical way to do

the job.

4. Check each pole and span to determine what work

can be performed prior to stringing.

5. Decide on the most suitable locations for setting upthe stringing equipment.

6. Ensure sufficient equipment, material and person-

nel will be available for the job.

7. Additional personnel may be required at various

locations to protect the public from possible safety

hazards arising during the stringing procedures.

8. Extra traffic control devices may have to be obtained

from other crews or rental centres.9. Obtain permits when stringing conductor over

major thoroughfares, railroads, etc. Police or the

railroad company may be required to assist. Make

arrangements well in advance of the project.


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202 PREPARATION FOR WORK

1. One person should be in charge to supervise and

co-ordinate the overall operation.

2. Conduct a tailboard talk prior to the commence-

ment of the job. If a change in procedure is neces-

sary during the stringing operation, everyone

should be informed of the change by means of

additional tailboard talks.

3. Items to be recorded and discussed during the

tailboard talk include:

(a) hazards of all types

(b) work location for each crew member

(c) methods of communication (two-way radio

hand signals, etc.)

NOTE: The person in charge of the overall job

should be the only person to order the

commencement of pulling. Anyone

noting a problem must immediately

communicate the need to cease

pulling.

Figure #1: Tailboard Talk decal


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(d) traffic control

(e) hazardous locations (road intersections or line

intersections, etc.)

(f) personal protective equipment

(g) work protection in effect (hold-off, work permits,

etc.)

(h) emergency plan


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SECTION III

TEMPORARY GROUNDINGAND BARRICADING OF EQUIPMENT

300 GENERAL PRECAUTIONS

301 PROCEDURES FOR SETTING UPGROUND GRADIENT MATS

302 PROCEDURE FOR SETTING UPSTRINGING EQUIPMENT

303 PROCEDURE FOR SETTING UP FENCEBARRIERS

304 PROCEDURE FOR GROUNDING THECONDUCTOR


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SECTION III

TEMPORARY GROUNDING AND

BARRICADING OF EQUIPMENT

300 GENERAL PRECAUTIONS

Follow proper grounding procedures when stringingconductor in proximity to other energized circuits.Whenever stringing conductors, use grounds toensure there is no possibility of inducing a charge onto

the conductors. Make consideration for induction fromhigh voltage circuits, even at distances of 150 m (500ft.) and more.

Properly grounding equipment and conductors is

essential. Therefore, appropriate sized ground leads,clamps, connections and reference to the systemprotective devices (i.e. fuses, reclosers, breakers andavailable fault current for the system) must be taken

into consideration.

Proper temporary grounding helps ensure the opera-tion of isolating devices and minimizes fault duration,

which is the objective of grounding. However, the rapidrupturing of fuses or tripping of reclosers may notentirely eliminate the possibility of dangerous potentialrises. Therefore, good electrical connections must bemade from the system protection to the conductor at

every opportunity throughout the project. The bestreturn route to the system protection is via the systemneutral. In some situations, it may be through groundprobes, or a combination of both.

All workers (except those necessary to operate themachinery) should stand clear of conductive equip-

ment during the stringing process. Those workersoperating machinery must be in an equipotential zone,

where the possibility of step or touch potential differ-ences has been eliminated.


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Equipotential zones are created by bonding and/or

grounding all metallic apparatus together (i.e. conduc-

tors, ground gradient control mats, reel stands, pullers

and tensioners).

301 PROCEDURES FOR SETTING UP GROUND

GRADIENT MATS

The purpose of the ground-gradient mat is to provide

an equipotential zone of adequate size upon which all

of the conductor stringing machinery can be be situ-

ated and all work activities, such as reel changing and

splicing, can be performed where no potential differ-ences could occur. If contact with another circuit

occurs, there is still the possibility of a potential rise of

tremendous magnitude before the system protection

activates no matter how well this equipment is

connected. The key to a safe work zone is to minimize

the possibility of this happening. Should an incident

occur that causes a potential rise, no one working in a

properly constructed equipotential zone will sustain

current flow through their bodies. Where there is no

current flow, there can be no electrical injury.

NOTE: The mat should be large enough to carry out

all work without stepping off the mat.

At the tension (pay out) end, work includes operating

the machine, changing reels and splicing conductors.

A space of 2.4 to 3 m (8 to 10 ft.) is necessary to splice

conductors behind a tension machine, without step-

ping off the mat.

1. A common ground-gradient control mat is a grid ofmetal galvanized steel, or high-flex copper braid,

strategically positioned on fabric. The design of the

mesh should be arranged so that workers will

always be bridging the grid with their feet, whether


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they are standing or walking on the mat. To accom-

plish this, the steel mat typically consists of a

minimum No. 10 gauge (0.1350) galvanized steel

wire, constructed in a 5 cm (2 in.) square mesh, 1.5m by 6 m (5 ft. by 20 ft.), or as required (ie. circum-

stances dictate the length and width of the mat). In

fact, most stringing operations require two or three

such mats bonded together. Ground gradient mats

should be laid into position whenever there are

adjacent circuits and/or the possibility of induction.

All conductor stringing equipment and related

activities should be carried out on the mats.

2. IHSA recommends that a 1/0 high flex copper cablebe positioned around the perimeter of each mat.

The cable shall be affixed to the mesh of the mat at

intervals not exceeding 0.90 m (3 ft.) to ensure

continuity at all times. A flex copper lead of at least

the same dimension or greater, should be con-

nected to a common point on the tensioning

machine.

NOTE 1: If the pulling machine will have direct

contact with a conductor (when pullingout existing conductors, and the pulling

line is metallic, or when the new con-

ductor has to be brought to the puller)

the puller shall also be placed onto a

ground gradient mat.

NOTE 2: Ground rods must be used when only

delta connected circuits are involved. At

each of the four corners of the layout,

ground rods are driven and connectedto the wire lead around the perimeter of

the mat. Where practical, drive as many

ground rods as necessary to obtain a

megger reading of 25 ohms or less.


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302 PROCEDURE FOR SETTING UP STRINGING

EQUIPMENT

After the ground gradient mats have been properly

installed to the dimensions required for the work area,

move the tension device, reel trailers and all related

equipment into place onto the mat. Any metallic

equipment on the mat must be bonded together by

suitable connectors to the lead running around the

perimeter of the mat, using 1/0 copper leads to the

grounding lugs on the equipment.

NOTE 1: The first and last travellers of the stringing

project should be grounded.

NOTE 2: Whenever another circuit t raverses theconductor being strung, the travellers on

either side must be grounded.

NOTE 3: If the pulling rope is metallic , wet, contami-

nated with dir t or aluminum, or the conduc-

tor is to be pulled to the pulling machine, it

must be placed on a ground gradient mat

in the same manner as the tension ma-

chine.

Pullers and tensioners shall be anchored, regardless

of the tension anticipated during the conductor string-

ing project. Weight change from the conductor at the

pay out end, or a sudden stop, could cause these

machines to shift. When the stringing equipment is

sitting on a ground gradient mat, it is critical that

conductive wire rope or chains do not extend beyond

the ground gradient mat. The use of web slings and

insulators will isolate the machines from the anchor.

303 PROCEDURES FOR SETTING UP BARRIERS

1. Nonconductive barriers should be installed around

the perimeter of the ground mat, to prevent person-

nel from straying on and off the mat except at a

controlled location. This controlled location is a 0.9


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m (3 ft.) opening for entry/exit. The barrier system

will also remind personnel that they should not

hand tools into and out of the zone when stringing

is in progress.

2. Approximately 0.9 to 1.2 m (3 to 4 ft.) outside this

barrier, another barrier (rope, tape, barricades, etc.)

should be installed around the enclosure Dan-

ger Live Apparatus signs should be hung on this

barrier.

3. At the entry/exit point, a pieceof plywood 0.9 m by

1.8 m by 1.3 cm (3 ft. by 6 ft. by in.), covered by a

nonconductive rubber or plastic mat, should be

placed so that one end is on the ground mat and

the other is clear of the barrier around the enclo-

sure. This is to protect personnel from step

potentials when entering or leaving the enclosure.

No personnel may enter or leave the enclosure

when stringing is in progress. (See Figure #2)

304 PROCEDURES FOR GROUNDING/BONDING

DURING STRINGING OPERATIONS

Considerable emphasis is placed on isolation tech-

niques and grounding procedures when using large

hydraulically-driven tension machines. However, there

is a tendency not to take the same precautions when

involved with routine stringing operations using small

tension brakes or reel brakes, in conjunction with reel

trailers even though the stringing may be done in the

area of energized equipment. The same precautions

should apply to routine stringing operations near

energized equipment as apply to major stringing jobsusing large hydraulically-driven tension machines.

The grounding/bonding of tensioning machines,

pulling machines, ground gradient mats, conductors,

and travellers is to create an equipotential work zone.


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This is a very important component in providing a safe

work zone for crew members and the general public.

Every effort taken during preparation to eliminate a

potential difference throughout the project will help

prevent injury should something go wrong.

Sometimes, through equipment failure, loss of control,

missed communication, oversights or misjudgements,

the conductor being strung contacts something that isenergized. Equipment may be damaged, power

interrupted, and the project delayed. However, if this

unplanned event causes no personal injuries, the

grounding/bonding has worked as designed.

Figure #2

Second physical

barrier

Ground matwire fabric

First physicalbarrier

1/0 strandedcopper bondinglead, threadedaround perimeterof mat andconnected tosystem neutral

Plywood covered with rubber mats, used to provide

entranceway in and out of enclosure

Equipmentrequiringground

mat

protection

Work area

inside

second

physicalbarrier

Setting up ground gradient mat area for stringing


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All grounding/bonding connections must be regarded

the same as making electrical connections. The lower

the resistance and the more direct path to the system

protection (fuses, reclosers, etc.), the more rapid theinterruption. Therefore, the preferred connections

would always be to the system neutral, when available.

In locations where a system neutral is not available, a

series of ground probes with 25 ohms or less resist-

ance is the next best choice. In rural areas, a combi-

nation of ground probes and the non multi-grounded

system neutral is necessary.

A ground gradient mat shall be used for the placementof the tension machine.

NOTE: The mat should be large enough to carry out

all work without stepping off the mat.

At the tension (pay out) end, work includes operating

the machine, changing reels and splicing conductors.

A space of 2.4 to 3 m (8 to 10 ft.) is necessary to splice

conductors behind a tension machine, without step-

ping off the mat.

In most instances, two or three separate mats will

need to be positioned to adequately encompass the

equipment placed upon it. Each mat used must be

bonded to a common bus to ensure an equipotential

work zone is created.

Bonding cable of 1/0 bare, braided or stranded copper

is threaded around the perimeter of the mat, then the

mat and lead (bonding cable) are connected together

with an appropriate connector, approximately every 0.9

m (3 ft.).

At an appropriate location, an extra flex lead, equipped

with an approved type grounding clamp should be

connected from the bonding lead to the system neutral.


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This lead should be a minimum of 1/0 extra flex

copper, and should be treated as a possible energized

conductor.

NOTE: Ground rods are required when working

with delta connected circuits. At each cor-

ner of the mat, ground rods would be

driven and connected to the bonding cable.

Where practical, sufficient ground rods

should be driven to obtain a megger reading

of 25 ohms or less.

Grounding/Bonding During Stringing Operations

To achieve the goal of establishing a safe work envi-ronment, the following setup would be considered as

necessary. (See Figure #3)

At the Reel

This is the first of a series of grounds to be applied.

Even though there are several types of tension ma-

chines in use, a standard method is used to ground

Figure #3

Conductor Travelling Ground

1/0 HighFlex Copper

Connect Tail ofConductor toReel Stand

Connect toSystem NeutralWhenever Available

Connect toDriven GroundRods when noNeutral isavailable

Neutral

1

2

3

4

Each section ofGrounding Matconnects to CommonGrounding Point

Connect to systemneutral wheneveravailableNeutral

Connectto driven

ground rodwhen noneutral isavailable

ConductorTravelling ground

Connect tail ofconductor toreel stand

Each section ofgrounding matconnects tocommongrounding point

1/0 extraflex copper


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the conductor on the tension stringing reels. On the

large hydraulic tension machines, a bonding lead is

connected from the tail of the conductor (projecting

through the reel) to the ground lug provided on thedrive arm of the tensioner. Internally, on the drive shaft,

a collector ring provides an electrical path, through a

set of brushes and extra flex copper, to an external

ground lug on the tensioner.

NOTE: This is the only opportunity to ground covered

conductor dur ing the stringing procedure.

Ahead of the Reel (Travelling Ground)

This is the second opportunity to ground the conductor.It maintains a high integrity connection to system pro-

tection throughout the entire run. To help ensure this:

a) the full capacity leads and clamps should be

thoroughly inspected and adequately tightened;

b) the entire circumference of the wire is involved;

c) the mechanism is spring loaded to accommodate

all irregularities in the conductor.

This ground will ensure continuity with the

equipotential zone around the tensioner. It will alsoensure the conductor is grounded as it passes up

through any underbuilt circuits. It is also move-able

and remains on the conductor tail as the conductor is

cut and lowered down through any underbuilt circuits.

The travelling ground is connected to the tension

machine using a 1/0 extra flex copper lead attached to

a common grounding point. (See Figure #4)

The ground gradient mat(s) are also connected to the

common grounding point. Another 1/0 lead is con-nected to either the system neutral or to ground

probes, as discussed earlier.


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First and Last Traveller

This is the third and last

point in the run to

ground the conductor.The conductor's angle of

deflection at these

travellers allows for

greater surface contact

between the conductor

and grounded travellers.

Pressure and increased

contact area between

these travellers and theconductor is desirable

to provide a good path to

ground. These may be

the only travellers in the

run that are able to be grounded.

When the conductor is cut after dead-ending, the

grounded traveller continues to provide some contact

with ground.

NOTE: Travellers with protective coatings on the

sheaves are not designed to be grounded.

General Rule: Fifth Traveller Grounding

This grounding will provide additional paths to ground

throughout the run.

In circumstances where induction could be present,

these multiple grounds will help ensure continual

draining of induced voltage. Should an inadvertent

contact occur, these grounds will help isolate the

offending circuit more rapidly. This is also the rationale

for grounding both sides of traversing energized

circuits.

Figure #4


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All workers must understand when grounding any

apparatus they are making electrical connections. The

same care is to be taken as if the device was being

connected to an energized medium to carry current.

The fault current during a short circuit could rise to tens

of thousands of amps. Any underrated, loose, or

corroded connections will fail, some with catastrophic

results.

The more paths to ground the better. The better the

connections, the more rapid the protection system will

operate; thereby providing a safer work environment.

(See Figure #5)

Figure #5

When full puller/tensioner machines are not used,

other types of tension devices are used, as shown in

Figure #6. Regardless of the type of tensioning or

pulling device used, the grounding procedure should

be adequate to protect the workers and the general

public. Equipotential work zones are always the

objective when grounding systems are being installed.

PullerGrounded

25 OHMs

25OHMs

TravellerGrounded

ConductorGrounded

TravellerGrounded Equipotential Work Zone

TravellerGrounded(Every 5th Structure)

Pulling End

Last Traveller 1st Traveller

Tension End

Pullergrounded

25 ohms

Pulling End

Last Traveller First Traveller

TravellerGrounded

Traveller Grounded(every fifthstructure)

TravellerGrounded Equipotential Work Zone

25ohms

Tension End

Conductor

Grounded


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Figure #6

Vertical pivoting action

Horizontal pivoting

action


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SECTION IV

CONVENTIONAL STRINGING METHODS

400 GENERAL

401 TENSION BRAKE DEVICES

402 PULLING DEVICES

403 MISCELLANEOUS EQUIPMENT

404 REMOVING OLD CONDUCTORS


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SECTION IV

CONVENTIONAL STRINGING METHODS

400 GENERAL

Conventional stringing methods would apply in cases

where constant, positive control of the conductor is not

required. In some instances (to clear driveways, trees,

etc.), a certain amount of conductor tension is neces-

sary. Most tension brake devices are suitable for this

application. However, in situations where absolute

control of the conductor is necessary, E&USA recom-

mends the use of full puller/tensioner conductorstringing machines.

401 TENSION BRAKE DEVICES

1. Several types of mechanical and hydraulic tension

brakes are available that will provide a certain

degree of control over the

conductor during a stringing

operation. However, they do

not have the capability of

reversing the direction of thepull.

2. Reel brakes in various

forms are used extensively

for conventional stringing

operations. Tension is

maintained by an adjustable

spring and brake band, and

the unit can be mounted on

all types of conductor reels.(See Figures #7 and #8)

3. A type of tension brake

device that will mount on a

truck or reel trailer is

Figure #7

Figure #8


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available. This unit will handle conductor sizes up

to 556 circular mils. The braking action is applied

by placing the conductor between a series of

bogey wheels and then adjusting a crank to forcethe wheels against the conductor. This unit is

designed to swivel both horizontally and vertically to

accommodate the pulling angle. (See Figure #9)

4. Another type of braking system being used is the

hydraulic disc brake. (See Figure #10) The use ofthis precision braking device is still categorized as

conventional stringing because it cannot be

reversed. This type of system can experience heat

buildup, therefore, installing a conductor grip as an

additional measure of safety is recommended if it

is left unattended. A pressure decline during

cooling could allow unexpected pay out.

Figure #9

Horizontal pivoting action

Vertical pivoting action


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402 PULLING DEVICES

1. When an appreciable degree of conductor tension

is required during a stringing operation, the con-

ductors can be pulled effectively using a capstan

head in conjunction with a truck-mounted deck

winch. The capstan head is not to be confusedwith the collapsible takeup reel, which is not

designed to safely withstand any significant degree

of tension. Its use should be restricted to slack

stringing operations or for installing pulling ropes.

Collapsible takeup reels should not have a build-

up of rope on them. They should only have enough

turns placed on them to effect the desired tension.

(Between three and six turns should be sufficient.)

Rope allowed to accumulate under tension willcause the reel to implode.

2. Boom tip winches should not be used to pull

conductor, since most are not designed for the

continuous operation typical of an extensive

Figure #10


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conductor stringing job. Such continuous operation

could cause winch components to overheat, which

could result in total loss of control of the conductor.


1. In order to carry out a conductor stringing operation

in a safe and efficient manner, various additional

pieces of equipment are necessary. This would

include appropriate travellers, conductor pulling

rope, pulling grips, swivels, connectors, a banding

tool and bands, running board, etc.

2. Travellers should be of the proper type and size for

each application and conductor size, and inspectedprior to use. Normally, the type of travellers shown

in Figure #11 are used throughout the run. How-

ever, severe corners and the first and last struc-

tures require larger travellers, as shown in Figure

#12. Along the run, the sheave size should range

from 10 to 17 cm (4 to 7 in.) with a load rating

Figure #11

Grounding Traveller


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capacity of 1134 kg. (2,500

lbs.). Where severe angle

changes occur, use a

larger traveller.

Sheave size should range

from 25 to 50 cm (10 to 20

in.) with a load rating

capacity of 1814 kg.

(4,000 lbs.). Three

sheave travellers are

available for simultane-

ous multi-conductor pulls

using a running board. Ifthe conductors are being strung individually, use

single sheave travellers. All travellers should be

equipped with a device which prevents the conduc-

tor from jumping out of the traveller.

3. Use an adequately sized synthetic pulling rope for

conductor stringing operations. The length of pull,

size and type of conductor being strung, and the

degree of tension involved will determine the

minimum size of rope.4. Use appropriate sized conductor pulling grips to

join the conductor to the pulling rope. Use a free

running swivel between the pulling rope and the

conductor pulling grip to prevent rotation of the

rope. Using a swivel to join the pulling grip on the

pulling rope with the pulling grip on the conductor,

will prevent build up of excessive torque. When

pulling conductor, the torque builds up rapidly as a

result of the pull on the synthetic rope by the pullingequipment. Using a straight pulling rope connector

would not allow this torque to dissipate. Two

recommended methods of attaching the conductor

to the pulling rope are:

Figure #12


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- to connect the swivel to a manufacturer ap

proved eye splice on the end of the rope, or

- to install a manufacturer approvedpulling grip

onto the pulling rope and apply locking as permanufacturers specifications bands (See

Figure #13)

Some types of pulling grips are equipped with a

permanent swivel on one end, however, a high

quality ball bearing swivel should also be used.

(See Figure #18)

When using a running board for multiconductor

stringing operations, swivels are necessary at all

running board connections to help prevent runningboard rotation and conductor entanglement.

5. Secure the tail end of all pulling grips to the con-

ductor (using a locking band) to prevent them from

accidentally slipping off. Locking bands must be

installed on the open end of all pulling grips, 2.5

cm (1 in.) from the end (see Figure #13). This is to

prevent the edges of the grip from catching on the

travellers and pulling the grip off. It is recom-

mended that the front (pulling end) of the grip be

Figure #13


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taped so the conductor will not come through the

aluminum shoulders on the grip.

(a) Conductor pulling grips should be banded as

shown in Figure #14.

Figure #14

(b) Conductor pulling grips that will run backward

or be reversed should also be taped, to prevent

any possibility of snagging, which could causesudden release. (See Figure #15)

Figure #15

(c) Conductor pulling grips that are worn or

frayed at the wire ends should have another

band applied before the taping process isdone. (See Figure #16)

Figure #16

404 REMOVING OLD CONDUCTORS

Existing conductors will need to be replaced. Since the

existing conductor is already in position, it could beused to pull in the conductor pulling rope or the new

conductor.

Several factors should be considered before proceed-

ing with this approach, including:

Double Bands End of Conductor


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35

- size and type of existing conductor

- age and condition of existing conductor

- age and condition of the existing structures includ-

ing guys

- location of other energized circuits

- degree of tension required while pulling

- size of new conductor to be installed

The old conductor should be visually inspected and

analyzed for defects prior to untying or unclamping.

Defects can be caused by age, lightning, accidental

contacts from trees, hoisting booms, etc.

If the conductor is of adequate strength and in goodcondition, it may be used to pull in the pulling rope or

the new conductor.

Grounding should be the same as it would be for

stringing new conductor, with one exception: the pulling

and pay out ends will have to be set up exactly as

discussed in Section 304 of this guide.

Automatic type sleeves should be removed before

proceeding. Non-compression (automatic) sleeves

are reliant upon multiple fingers gripping the outside

sur-face of the conductor strands. The tension is

constant and the loading is linear (in-line). As the

tension increases, the fingers grip more firmly into the

outside strands as they are forced into the tapered

barrel of the sleeve. Axial loading and fluctuations in

loading will cause failure (e.g. sudden release of

tension could cause the fingers to lose their grip), and

axial loading will cause the hollow barrel of the centre

to collapse.

Preparing the old conductor for removal

1. Automatic sleeves should be replaced with either

compression sleeves or conductor pulling grips.

Defects found during the visual inspection and


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36

dead-ends should be removed, and the conductor

connected end-to-end.

2. Installing conductor pulling grips back-to-back will

act as a temporary solution. However, doing so

requires that the grip leads be attached together.

This can be done in

several ways:

(a) An alloy steel

connector of the

appropriate

strength can be

used if it is wire

on either side. (See Figure #17)

(b) An alloy steel swivel of the appropriate strength

can be used if it is a wire-to-wire situation and

should be used if rope is on one side and wireon the other. (See Figure #18)

(c) An approved alloy connecting link may be used

where a swivel is not required. (See Figure #19)

NEVER run swivels or

connecting links onto

bullwheels or conductor

reels. They are not

designed for side loading,

which would happenwhen wrapped around a

bullwheel or reel.

NEVER use a non-rated

threaded link for conductor stringing.

Figure #17

Figure #18

Figure #19


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SECTION V


500 GENERAL


502 PULLING ROPES


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38

SECTION V


500 GENERAL

Although there has been a reasonable degree of

success tension stringing with conventional braking

devices, these devices should not be used during

operations where the absence of constant, positive

control of the conductor could create a safety hazard.


Hydraulically-driven puller/tension machines, like the

one shown in Figure #20, are the accepted standardfor true tension stringing operations. At least two

Figure #20


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machines are necessary for single conductor stringing

one as a pulling device and the other as a tensioner.

Both machines are essentially the same. However, the

pulling device would be adjusted to produce slightlymore tension than the tensioning device. Conse-

quently, should the pulling line or conductor snag, the

entire operation will cease without introducing a

significant increase in line tension.

One definite advantage of this type of machine is its

ability to operate in either direction under desired

tension or speed. Therefore, a snagged conductor or

pulling line can be more easily cleared than with

conventional types of equipment. Also, both machines

will react immediately to remove unexpected slack.

All travellers, swivels, connectors, running boards, and

pulling grips that are normally used during conven-

tional stringing operations may also be used in

conjunction with tension stringing techniques, provided

it is of adequate size and strength for the job at hand.

502 PULLING ROPES

1. During tension stringing operations, experience

has shown that the main pulling rope (bull rope)

can be installed more easily if a smaller diameter

synthetic rope (pea line) is first installed through

the travellers, and used to pull in the pulling rope.

The suggested size for this pea line would be a

minimum of 10 mm (3/8 in.) in diameter.

2. The main pulling rope should be a synthetic rope of

the appropriate size. Many stringing operations

use a 19 mm (3/4 in.) diameter two-in-one braided

rope. Several speciality ropes are being manufac-

tured for conductor stringing. Double braid polyes-

ter sheath, polyester core and hollow braided

polyvinyl coated polyester ropes are preferred.


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These ropes should have a minimum breaking

strength of approximately 7,439 kg (16,400 lbs.),

which will be adequate to safely handle most

tension stringing operations on distribution plant.

NOTE: Visually inspect the pulling rope before

using it and remove from service any

rope found to be damaged. Some types

of rope can be field spliced; others re-

quire sophisticated splicing procedures.

These ropes may be joined using back-

to-back conductor pull ing grips banded

for security. Refer to the rope manufac-

turer specifications for approved meth-ods.


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Bare Hand Live Line

Techniques

Conductor Stringing

Entry and Work in a

Confined Space

Excavating with

Hydrovacs in the

Vicinity of Underground

Electrical Plant

High Voltage Rubber

Techniques up to 36 kV

Hydraulics

Ladder Safety

Line Clearing Operations

Live Line Tool Techniques

Low Voltage Applications

Pole Handling

Ropes, Rigging and

Slinging Hardware

Temporary Grounding

and Bonding Techniques

Underground Electrical

Systems

Available Safe Practice Guides

Documents

Conductor Stringing