Guide to Live LV Electrical Work (March 2005)

8/12/2019 Guide to Live LV Electrical Work (March 2005)

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15 March, 2005 Guides:\Guide to Live LV Electrical Work (March 2005) 1

Guide to Live LV Electrical Work

March 2005


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1. INTRODUCTION

1.1 Intent of Guide

This guide has been prepared to provide electrical workers with guidance on howto control risks inherent in live LV work and document techniques to enable live

LV work to be carried out in a safe manner.

The guide is intended to be read in conjunction with the Electricity EngineersAssociation publications Safe Practices for Low Voltage Electrical Work andSafety Manual Electricity Industry (SM-EI) July 2004.

1.2 Legislation and Other Related Requirements

The requirements for working on LV conductors within the electricity supplyindustry, are governed by a number of regulations, codes of practice, standardsand industry best practice guidelines.

1.2.1 Regulations

Electricity Regulations (1997)

(a) Regulation 29 covers work on live conductors of LV overheadlines in electrical installations. It covers those parts of overheadlines which belong to customers. When working on such linesand there is exposed live metal or the likelihood of contact,associated equipment and personal protective equipmentnecessary to ensure safety must be used.

(b) Regulation 31 covers the construction of overhead lines onexisting poles or other supports. Where any additionalconductors are being strung between poles or supports already

holding conductors then either the existing conductors must beisolated and earthed or the additional conductors are earthedand applicable associated equipment is used.

(c) Regulation 35 requires the employer to ensure the safety ofemployees. In particular the employer must provide safeworking procedures for employees to follow when carrying outprescribed electrical work and ensure that associated equipmentand personal protective equipment is safe for the employee touse. The employer must also ensure that employees haveadequate knowledge and experience of the type of work beingcarried out, be adequately trained in the safe use of associatedequipment, personal protective equipment and the procedures.

Employees must also check that associated equipment and PPEis in good condition and use the equipment and procedures.

(d) Regulation 37 covers the testing of prescribed electrical work,and requires testing to ensure operational safety, and that thework does not reduce the safety of existing works.

(e) Regulation 69 requires works and associated equipment to beelectrically safe.

(f) Regulation 87 covers compliance with regulation 69 andrequires, amongst other requirements, that connections betweenconductors and between conductors and other fittings are safe

and reliable.


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1.2.2 Electrical Codes of Practice

New Zealand Electrical Code of Practice for Electrical Safe DistancesNZECP 34:2001

ECP 34 sets minimum safe electrical distance requirements for

overhead electric line installations and other works associated with thesupply of electricity.

The minimum distances have been set primarily to protect persons,property, vehicles and mobile plant from harm or damage fromelectrical hazards. The distances are also a guide for the design ofelectrical works within substations, generating stations or similar areaswhere electrical equipment and fittings have to be operated andmaintained.

1.2.3 Industry Best Practice Guidelines

(a) Safety Manual Electricity Industry (SM-EI) (July 2004)

(i) Rule 3.710 covers work associated with installation ordismantling of LV conductors where contact with orinduction from other conductors could occur.

(ii) Rule 3.721 covers work on live LV overhead conductors.

(iii) Rule 3.731 covers work on live LV cables.

Note: Safety Manual Electricity Industry (SM-EI) whereadopted by an asset owner or contractor is mandatory.

(b) EEAGuide to Safe Practices for Low Voltage Electrical Work

The EEA publication Safe Practices for Low Voltage ElectricalWork provides the requirements for safe work on LV systemsgenerally.

(c) EEA Guide to Portable Equipment for Work On or NearConductors

The EEA publication Portable Equipment for Work On or NearConductors provides guidance on selected purchasespecification, and the inspection and testing requirements ofportable equipment used on;

(i) HV conductors for the purpose of isolation, testing, andearthing; and

(ii) LV conductors for temporary insulation.

(d) EEAGuide to the Identification of and Work on Cables

The EEA publication Identification of and Work on Cablesprovides guidance on the requirements for identifying andmaking safe HV and LV power cables, and for working on LVpower cables, including live cables.


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(e) Line Mechanics Handbook

The EEA Line Mechanics Handbook, 5th edition 2004, providesguidance and training information for line mechanics who workon electricity supply industry assets, including LV overheadconductors. The Handbook covers the theory applicable to

electrical systems, support structures and maintenancetechniques, as well as practical guidance on how to carry outvarious tasks.

1.3 Definitions

For the purpose of this guide, the following definitions apply:

1.3.1 Approved- Have a relevant organisations endorsement for a specifiedfunction.

1.3.2 Brush Contact- Momentary accidental contact.

1.3.3 Competent An employee is competent when they can demonstrateto their employer, at any time, that they have the necessary knowledge,skills and experience to carry out the work safely and to the standardsused by the employer, having acquired through training, qualificationand experience the knowledge and skills to correctly perform the taskrequired.

1.3.4 Conductor- Bare conductor or conductor not insulated to full workingvoltage (unless the context conveys another meaning). Conductorincludes conductive parts.

1.3.5 De-energized - Not connected to any source of electrical supply butnot necessarily at zero voltage (eg. may have an induced voltage).

1.3.6 Discharge - The removal of an electric charge by the application of asuitable discharge device.

1.3.7 Disconnected - Physically separated from any source of electricalenergy, isolated where necessary and secured in a position clear ofany electrical equipment that is capable of being energised.

1.3.8 Earthed Effectively connected to the general mass of earth:

(a) If protective devices are fitted, in a manner that ensures theelectrical isolation of any defective equipment through theoperation of the protective devices; or

(b) in a manner that ensures the removal of any charge.

1.3.9 Electrical worker- A person engaged in the installation, maintenance,repair, alteration, testing or fault finding on electrical equipment,including the supervision of such work.

1.3.10 Energised (live) Electrically livened, or connected to or containingsome other source of energy (eg. steam, compressed air, hydraulicenergy, spring under compression, tension or torsion, etc).

1.3.11 Equipment (electrical) - Apparatus, transmission/distribution lines,cables, and circuits, or plant (electrical, mechanical, civil) that can be

removed from service and which, when it is removed from service, ifenergised or put back into service inadvertently, could be a hazard to


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employees and other persons. Such equipment is typically fixed inlocation, and used for the generation, transmission and distribution ofelectricity. Such equipment is typically personal protective equipment,mobile or portable equipment and is used for maintenance orconstruction.

1.3.12 Exposed conductors - Electrical conductors and parts, approach towhich is not prevented by a barrier of rigid material in good order or byinsulation that is adequate for the voltage concerned and that is insound condition.

1.3.13 Fault finding - The process of making measurements or carrying outtests on equipment to locate faults. It may also include the process ofconnecting testing instruments or devices to various parts of theequipment to determine how the equipment is operating.

1.3.14 Hazardous area - An area in which an explosive atmosphere ispresent or may be expected to be present, in quantities such as torequire special precautions for the construction, installation and use of

electrical equipment.

1.3.15 Insulated - Separated from adjacent conducting material by a non-conducting substance permanently providing resistance to the passageof current, or to disruptive discharges through or over the surface of thesubstance or space, to obviate danger of shock or injurious ordamaging leakage of current.

1.3.16 Isolated Deliberately disconnected from external sources of harm,eg. energy (electrical or mechanical) or asphyxiating, toxic orflammable gas, and rendered incapable of being reconnected withoutpredetermined deliberate action.

Notes:

1. Isolation can be achieved by opening disconnectors, closingvalves or similar actions.

2. Where practicable, points of isolation shall be tagged in theisolated position.

3. Despite equipment being isolated, it may still contain hazards,eg. induced voltage, LV supplies, stored energy, toxic gas.

1.3.17 Isolator - A device which for reasons of safety, provides in the openposition, breaks appropriate to the voltage and the insulating medium.

1.3.18 Personal protective equipment (PPE)- Items that electrical workerscan use to protect themselves against a hazard.

1.3.19 Secondary point of contact- A conductive or semi-conductive objectat a different potential from the live conductor to be worked on. Thegeneral mass of earth is to be considered a secondary point of contact.

1.3.20 Testing - The use of logical methodology or test instruments or testequipment by a competent person.

1.3.21 Voltage - Differences of potential normally existing betweenconductors and between conductors and earth as follows:


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(a) Low voltage (LV) - exceeding extra-low voltage but notexceeding 1000 V a.c. or 1500 V d.c.

(b) High voltage (HV) - exceeding low voltage

2. SAFETY EQUIPMENT

2.1 Insulating Gloves

All insulating gloves should be either class 0 or 00 rated or other equivalentrating and comply with ASTM D120 Specification for Rubber Insulating Glovesor an equivalent internationally recognised Standard. It is electricity supplyindustry practice that insulating gloves be clearly identified with their maximumsafe working voltage and that inspection of safety equipment, including insulatinggloves, be carried out at six monthly intervals.

Inspection alone is considered inadequate by the industry to ensure thecontinuing safety of insulating gloves used for protection against LV.

Accordingly, it is the practice of the industry, as a practicable step to safeguardemployees, to also test LV insulating gloves at the required inspection intervalsand mark their container with a next due for test date.

A recording system must be used to record the scheduled inspections, tests andservice lives of insulating gloves. For tracking and recording purposes, thegloves should be marked with a unique identifying number. Gloves that do notcarry the required information, including the next due for test date, must not beused; instead they must be withdrawn from service until they have been re-tested, found to be safe and adequately marked.

Immediately prior to use, the gloves should be visually checked for defects thetest certification for currency i.e. not past the next due for test date and then

tested for any air leaks through cuts and weak spots. This is best done by rollingthem up tightly, beginning at the cuff end, and noting if air escapes. Always useover-gloves for mechanical protection wherever practicable. Insulating glovesshould be kept in special containers to prevent damage in storage or beingtransported.

Note:Insulating gloves for use on LV are available with protective ratings for upto 650V AC nominal maximum voltage and 1000V AC nominal maximum voltageand the correctly rated gloves must be selected for the nominal voltage of theequipment to be worked on.

2.2 Insulating Boots

All insulating boots should be either dielectric boot design for over foot with steeltoe or dielectric over shoe boots rated to a standard at least equal to theequivalent of ASTM class 0 or class 00, or an equivalent internationallyrecognised Standard. It is electricity supply industry practice that insulatingboots be clearly identified with their maximum safe working voltage and thatinspection of safety equipment, include insulating boots, be carried out at sixmonthly intervals.

Inspection alone is considered inadequate by the industry to ensure thecontinuing safety of insulating boots used for protection against LV. Accordingly,it is the practice of the industry, as a practicable step to safeguard employees, toalso test LV insulating boots at the required inspection intervals and mark theircontainer with a next due for test date.


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A recording system must be used to record the scheduled inspections, tests andservice lives of insulating boots. For tracking and recording purposes, the bootsshould be marked with a unique identifying number. Boots that do not carry therequired information, including the next due for test date, must not be used;instead they must be withdrawn from service until they have been re-tested,found to be safe and adequately marked.

Immediately prior to use, the boots should be visually checked for defects, thetest certification for currency (ie. not past the next due for test date), and thentested for any air leaks through cuts and weak spots. This is best done by rollingthem up tightly, beginning at the cuff end, and noting if air escapes. Insulatingboots should be kept in special containers to prevent damage while in storage orbeing transported.

Insulating boots are only to be used for actual live LV work. Alternativeprotective footwear is to be used for all other activities including preparation forand tidy up after the actual live work.

Note:Insulating boots are available in a range of protective ratings and correctly

rated boots must be selected for the nominal voltage of the equipment to beworked on.

2.3 Insulating Covers and Blankets

All insulating covers and blankets should be class O rated and comply withD1049, Specification for Rubber Insulating Covers or ASTM D1048Specification for Rubber Insulating Blankets, or an equivalent internationallyrecognised Standard. It is electricity supply industry practice that insulatingcovers and blankets be clearly identified with their maximum safe workingvoltage and that inspection of safety equipment, including insulating covers andblankets, be carried out at six monthly intervals.

Inspection alone is considered inadequate by the industry to ensure thecontinuing safety of insulating covers and blankets used for protection againstLV. Accordingly, it is the practice of the industry, as a practicable step tosafeguard employees, to also test LV insulating covers and blankets at therequired inspection intervals and mark their container with a next due for testdate.

A recording system must be used to record the scheduled inspections, tests andservice lives of insulating covers and blankets. For tracking and recordingpurposes, the covers and blankets should be marked with a unique identifyingnumber. Covers and blankets that do not carry the required information,including the next due for test date, must not be used; instead they must bewithdrawn from service, until they have been re-tested, found to be safe and

adequately marked.

Immediately prior to use, the covers and blankets should be visually checked fordefects such as cuts, abrasions or cracking, the test certification for currency i.e.not past the next due for test date. Insulating covers and blankets should bekept in special containers to prevent damage while in storage or beingtransported.

Note: Insulating covers and blankets for LV are available with protective ratingsfor up to 650V AC nominal maximum voltage and 1000V AC nominal maximumvoltage and the correctly rated insulating covers and blankets must be selectedfor the nominal voltage of the equipment to be worked on.


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2.4 LV Safety Mats

All LV safety mats should be specifically manufactured for foot traffic with arating to a standard at least equal to the equivalent of AS/NZS 2978-1995Insulating Mats for Electrical Purposes class A, or an equivalent internationallyrecognised Standard. It is electricity supply industry practice that insulating mats

be clearly identified with their maximum safe working voltage and that inspectionof safety equipment, including insulating mats, be carried out at six monthlyintervals.

Inspection alone is considered inadequate by the industry to ensure thecontinuing safety of LV Safety mats used for protection against LV. Accordingly,it is the practice of the industry, as a practicable step to safeguard employees, toalso test LV safety mats at the required inspection intervals and mark theircontainer with a next due for test date.

A recording system must be used to record the scheduled inspections, tests andservice lives of LV safety mats. For tracking and recording purposes, the matsshould be marked with a unique identifying number. Mats that do not carry the

required information, including the next due for test date, must not be used;instead they must be withdrawn from service until they have been re-tested,found to be safe and adequately marked.

Immediately prior to use, the mats should be visually checked for defects suchas cuts, abrasions or cracking, the test certification for currency i.e. not past thenext due for test date. LV safety mats should be kept in special containers toprevent damage while in storage or being transported.

Note: LV safety mats are available with protective ratings for up to 650V ACnominal maximum voltage and 1000V AC nominal maximum voltage and thecorrectly rated safety mats must be selected for the nominal voltage of theequipment to be worked on.

2.5 LV Line Hose

All LV line hoses should be of an adequate rating to a standard at least equal tothe relevant NZ standard or an equivalent internationally recognised Standard. Itis electricity supply industry practice that insulating hose be clearly identified withthe maximum safe working voltage and that inspection of safety equipment,including LV line hoses, be carried out at six monthly intervals.

Inspection alone is considered inadequate by the industry to ensure thecontinuing safety of LV Line Hoses used for protection against LV. Accordingly,it is the practice of the industry, as a practicable step to safeguard employees, toalso test LV insulating mats at the required inspection intervals and mark their

container with a next due for test date.

A recording system must be used to record the scheduled inspections, tests andservice lives of LV line hoses. For tracking and recording purposes, the LV linehoses should be marked with a unique identifying number. LV line hoses that donot carry the required information, including the next due for test date, must notbe used; instead they must be withdrawn from service until they have been re-tested, found to be safe and adequately marked.

Immediately prior to use, LV line hoses should be visually checked for defectssuch as cuts, abrasions or cracking, the test certification for currency i.e. not pastthe next due for test date. LV line hoses should be kept in special containers toprevent damage while in storage or being transported.


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Note: LV line hoses are available with protective ratings for up to 650V ACnominal maximum voltage and the correctly rated LV line hoses must beselected for the nominal voltage of the equipment to be worked on.

2.6 Insulating Tools

All insulated tools and equipment should of a rating at least equivalent to BSEN60900:2004 (Live Working Handtool for use up to 1000V a.c. and 1500V d.c.), oran equivalent internationally recognised Standard. It is electricity supply industrypractice that insulated tools and equipment be clearly identified with theirmaximum safe working voltage and that inspection of safety equipment,including insulated tools, be carried out at six monthly intervals.

Inspection alone is considered inadequate by the industry to ensure thecontinuing safety of insulated tools used for protection against LV. Accordingly,it is the practice of the industry, as a practicable step to safeguard workers, toalso test LV insulating tools at the required inspection intervals and mark theircontainer with a next due for test date.

A recording system must be used to record the scheduled inspections, tests andservice lives of insulating tools. For tracking and recording purposes, the toolsshould be marked with a unique identifying number. Insulating tools that do notcarry the required information, including the next due for test date, must not beused; instead they must be withdrawn from service, until they have been re-tested, found to be safe and adequately marked.

Immediately prior to use, the insulating tools should be visually checked fordefects such as cuts, abrasions or cracking, and the test certification for currencyi.e. not past the next due for test date. Insulating tools should be kept in specialcontainers to prevent damage while in storage or being transported.

Note: Insulating Tools are available with protective ratings for up to 1000V AC

nominal maximum working voltage and the correctly rated tools must be selectedfor the nominal voltage of the equipment to be worked on.

3. GENERAL PRINCIPLES

Any work to be undertaken on or within 150mm of live LV conductors is considered tobe live work in the context of this guide. No live LV work is to be undertaken inhazardous areas.

3.1 Techniques

3.1.1 Gloved Hand

Use of appropriately rated insulating gloves with over gloves to provideprotection.

3.1.2 Bare Hand

(a) Use of appropriately rated insulated footwear consisting ofinsulated boots, shoes, or over boots, to provide protection.

(b) This technique requires all points of possible secondary contactto be covered up with insulated cover during the live work.

(c) Electrical workers shall not touch each other, nor hand each

other tools while a worker is in contact with a live conductor.


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(d) It is recommended that LV safety mats be used in conjunctionwith insulated footwear where the insulated footwear is notspecifically design for primary protection.

3.1.3 Insulated Tools

Use of appropriately rated insulated tools and equipment to provideprotection.

3.2 General Precautions with Live LV Conductors

When electrical workers are working on live LV conductors, the followingprecautions shall be observed in addition to those set out in SM-EI rule 3.721Work on Live LV Overhead Conductors:

All conductors are to be treated the same as live exposed conductors unless theconductor insulating covering is found to be in a satisfactory condition and ratedfor the voltage. For the purpose of this neutral conductors are to be treated aslive conductors.

No two conductors may be bared at the same time (except for the purpose ofconnecting them together) if one bare part can be reached while working on theother. When work is completed on one conductor, it shall be re-insulated beforework is commenced on another.

(a) Where conductors are to be joined or terminated:

(i) Any exposed ends of conductors are to be restrained to preventaccidental contact with surfaces at different potentials.

(ii) The conductors to be connected are to be tested to ensure they areat the same potential and phase. Where new or modified

conductors are installed the requirements of the ElectricityRegulations are to be carried out. Consideration also needs tobe given to the connection method where potential load current mayexist due to a connected load.

(b) Where conductors to be worked on may become live, they are to betreated as live conductors.

(c) Where conductors are connected to devices containing stored energy,they are to be treated as live until the device has been discharged.

(d) Before energising a conductor by connecting it to a live conductor, a testshall be made to check that it is safe to do so.

(e) When two electrical workers are working within reach of each other, theyshall not work on different phases or on a phase and a neutral, and toolsshall not be passed to a worker in contact with a live conductor. Electricalworkers shall keep clear of earthed metal such as telephone wires, staywires, messenger wires, cable potheads and sheaths, earth wires,transformer cases, street light brackets and steel or concrete poles andstay bars (crossarm braces) on such poles. Where it is not possible for anelectrical worker to keep a safe distance from such earthed metal,insulating covers shall be applied to it.

3.3 Secondary Points of Contact

When planning work an assessment of the work area needs to be conductedidentifying all live or potentially live conductors, and conductors or conductive


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surfaces at different potentials, to enable the 150mm minimum approachdistance for LV to be maintained from these surfaces. For the purpose of this,the earthing of all exposed metal including the lead sheaths, neutral screens orarmouring of cables, needs to be considered.

All secondary points of contact that are identified including any exposed metal in

or adjacent to the planned work area that may present a brush contact hazardduring the live work should be covered up using rated covers, mats, barriers,tubing etc.

3.4 Worksite Safety Plan

As required by SM-EI, prior to the commencement of work, a worksite safetyplan is to be established. For live LV work this should include but not be limitedto:

(a) A thorough assessment of work site for potential hazards paying particularattention to prevention of access into the work area of other parties andthe general public, weather conditions if outside and lighting.

(b) A method of hazard management for each identified hazard.

(c) An assessment of the condition of conductor insulation or covering shouldbe carried out in planning where additional cover up may be required.

(d) Identification of personal protective equipment required.

(e) The scope of the work to be undertaken.

(f) The competencies of the electrical workers to undertake respective worktasks.

(g) Work procedure to be used including the selection of adequately rated liveLV protective equipment.

3.5 Personal Protective Equipment

For work on live LV equipment, industrial work wear, including overalls shall beworn at all times so that the body is fully covered including arms, torso and legsand shall be a minimum of 100%/185gsm cotton or flame retardant and shallhave no metal fittings, unless they are protected by a layer of the same materialas that of the garment on both the top and undersides.

Eye protection is to be worn for the duration of live LV work consisting of suitableprotective glasses, goggles or face shield. Anti-glare eye protection should be

used as appropriate.

3.6 Electrical Worker Competency

Only electrical workers who are competent to undertake the task intended to becarried out live when the line or equipment is in a de-energised state, anddeemed competent by their employer or supervisor to do so, shall undertake liveLV work. Where a worker is undergoing training in live LV work, directsupervision must be provided for the duration of the live work activity.

3.7 Safety Observer

It is recommended that a safety observer who is competent in the task to be

undertaken is appointed for the duration of the live LV work activity.


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3.8 Low Voltage Networks

Electrical workers should make themselves familiar with the layout of lines in thearea in which they are working. Special care is required when working on LVlines that are interconnected and supplied from more than one transformer.

Before any connection is made at a line break termination, employees shallcorrectly identify the phase and neutral conductors.

Note: Phasing may be identified by a disc system.

3.9 Phase Position of Lines

The relative positions of the phase conductors and the neutral conductor shouldbe standard throughout each electricity distributor's supply system. This may notalways be the case and it shall be the responsibility of every electrical worker tofamiliarise themselves with the system of phase positioning in the area in whichthey are working. Particular attention shall be paid to identifying the neutralconductor.

3.10 Connection of Services

When connecting or reconnecting a service, an electrical worker shall ensurethat the connection is correctly made by appropriate testing as required by theElectricity Regulations. Before connecting the service, a positive identificationshall be made of the house neutral, the main neutral and the street main neutral;if this is not possible, the service shall not be connected.

3.11 Working on Auxiliary Circuits

When working on any auxiliary circuits, (eg. street lighting, pilot, control,communications, etc), precautions may be made necessary by the high voltages

which can appear due to:

(a) the capacitive effect where they parallel an HV circuit; or

(b) the inductive effect where they parallel a fault carrying circuit.

4. WORK ON LIVE LV OVERHEAD CONDUCTORS

Before commencing work on live LV overhead conductors, an electrical worker shall:

(a) Wear insulating gloves:

(i) The minimum class of glove shall be Class OO 500 volt working.

(ii) Insulating gloves shall be worn at all times whilst aloft.

(b) Cover with insulating material every part of such conductors (except theconductor on which work is being carried out) that could come in contact withany part of the body during the course of the work. If the conductor insulatingcovering is found to be satisfactory, and if there are no binders, line taps,clamps, preformed terminations and other fittings attached to the conductor inthe proximity of the work, then conductor cover-up gear need not be used.

(i) For the purpose of this requirement, the neutral conductor shall beregarded as a live conductor.


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(ii) An assessment of the condition of conductor insulation or covering shouldbe carried out in planning where additional cover up may be required.

(c) Secondary points of contact are to be identified including any exposed metal inor adjacent to the planned work area. All such points of contact that may presenta hazard during the live work should be covered up using rated covers, mats,

barriers, tubing etc.

5. WORK ON LIVE LV CABLES

One of the following methods of work shall be used:

5.1 Gloved Hand

(a) Appropriately rated insulating gloves shall be worn by all workers involvedin jointing live conductors.

(b) Where the jointing is to take place in a joint hole the hole is to be prepared

in such a manner to provide a level dry work surface on which to work.

(c) All exposed earthed metal, including lead sheaths, neutral screens orarmouring of cables in the immediate working area, shall be effectivelyinsulated using coverup.

(d) Only one core of the cable being worked on shall be made bare at a time,and the jointing work on each core shall be completed and the core re-insulated before a second core is made bare.

(e) When jointing a de-energised cable to a live cable, the worker shall ensurethat the de-energised cable is tested to meet the requirements of theElectricity Regulations before and after any connections are made.

(f) Where a live cable is to be jointed to a cable already live, only one core ofeach cable shall be made bare at a time. These cores shall be testedbefore any connection is made between them in order to ensure that theyare at the same potential and phase.

5.2 Bare Hand

(a) Electrical workers shall adequately insulate themselves from earth, andfrom all exposed earthed metal and the general mass of ground. To dothis, the floor and sides of the joint hole shall be covered with dryinsulating material. The floor of the joint hole shall be free of sharp objectsand be maintained in a level and dry state.

(b) Electrical workers shall wear appropriately rated insulating rubber boots,shoes or over boots.

(c) All exposed earthed metal within the joint hole, including the lead sheaths,neutral screens or armouring of all cables, shall be effectively insulatedbefore the live core of any cable is made bare and shall not be uncovereduntil the cores of the cable have been re-insulated.

(d) Electrical workers and any assisting workers shall not touch each other,nor hand each other tools while either is in contact with a live conductor.

(e) Only one core of the cable being worked on shall be made bare at a time,

and the jointing work on each core shall be completed and the core re-insulated before a second core is made bare.


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(f) When jointing a de-energised cable to a live cable, employees shallensure that the phase cores of the de-energised cable are insulated fromother conductors, from one another and from earth, before anyconnections are made.

(g) Where a live cable is to be jointed to a cable already live, only one core ofeach cable shall be made bare at a time. These cores shall be testedbefore any connection is made between them in order to ensure that theyare at the same potential and phase.

6. INSTALLATION OR REMOVAL OF LV CONDUCTORS ON POLES CARRYING LIVECONDUCTORS

(a) Insulating gloves shall be worn at all times when handling the conductor untilsuch time as the conductor is terminated, earthed, and bound in. In addition,insulating boots or over boots may be worn. These requirements need not applywhen all the following conditions apply:

(i) The conductor being run out or removed is covered with rated PVCinsulation.

(ii) The live conductors are LV and are also rated PVC insulation covered andtheir covering has been examined and found to be satisfactory.

(iii) The covering of all binders, line taps, clamps, preform terminations andother fittings attached to the conductors is equally satisfactory.

(b) No electrical worker shall be on or supported by any crossarm while a conductorsupported by that crossarm is being run out or removed, or while a conductor isbeing tensioned or released.

(c) The conductor drums or coils shall be under the control of an electrical worker.They shall be positioned sufficiently far from the first pole, at least 40 metreswherever possible on flat ground, to avoid excessive vertical loading on thecrossarm on which the conductor is being run and to prevent the loose-end flyinginto a live conductor.

(d) A dry insulating hand line shall be attached to the conductor to pull or guide itover the crossarm.

(e) The conductor shall be in sight for its full length and there shall be an agreedmethod of signalling in order to stop pulling should a conductor foul anobstruction or lift dangerously close to the live conductors.

(f) An effective method of temporarily earthing bare conductors at the drum or onthe crossarm of the first pole shall be arranged.

(g) Observers shall be stationed at intervals along the line and, where necessary,they shall use a dry insulating hand line to prevent the new conductorscontacting a live conductor.

(h) All conductors being run under live HV lines shall be earthed immediately theyare terminated or held at one end, and before any attempt is made to tension theconductor.

(i) With bare conductors, before cutting these clear from the drums and removing

the running earths, temporary earths shall be applied in the first span ofconductor from the drum.


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15 M h 2005 G id \G id Li LV El i l W k (M h 2005) 17

(j) When tensioning heavy conductors under light HV conductors, care shall betaken to ensure that termination or angle poles are well blocked or stayed toprevent the pull on the heavy conductors either over tensioning the lightconductors or increasing the sag of the light conductors to bring them down onthe LV conductors. When tensioning light LV conductors under heavy HV

conductors, care shall be taken to ensure that the light conductors are not pulledup into the heavy conductors.

(k) Care must be taken when removing conductors. When a conductor is beingtaken down, it shall be anchored before being cut to avoid sudden release oftension.

(l) Particular care should be taken when handling any conductor, such as winchropes, fencing wire, wires on the ground, etc, where there is a possibility of theseconductors contacting live conductors.

7. WORK ON OTHER LIVE ELECTRICAL EQUIPMENT

Where live LV work is to be carried out on equipment other than overhead line andunderground or surface mounted cable systems the following should be applied:

(a) Gloved hand and/or insulated tool, or insulated footwear or matting and/orinsulated tool techniques should be used to provide protection for the electricalworker. It is recommended that the combination be used to provide addedprotection against brush contact either by un-insulated tools or the worker.

(b) An assessment of the condition of conductor insulation or covering should becarried out in planning where additional cover up may be required.

For the purpose of this requirement, the neutral conductor shall be regarded as a

live conductor.

(c) Secondary points of contact are to be identified including any exposed metal inor adjacent the planned work area. All such points of contact that may present ahazard during the live work should be covered up using rated covers, mats,barriers, tubing etc.

(d) No two conductors may be bared at the same time (except for the purpose ofconnecting them together) if one bare part can be reached while working on theother. When work is completed on one conductor, it shall be re-insulated beforework is commenced on another.

(e) Before energising a conductor by connecting it to a live conductor, a check by

testing shall be made that it is safe to do so.

(f) When two electrical workers are working within reach of each other, they shallnot work on different phases or on a phase and a neutral, and tools shall not bepassed to a worker in contact with a live conductor. Electrical workers shall keepclear of earthed metal such as telephone wires, stay wires, messenger wires,cable potheads and sheaths, earth wires, transformer cases, metal brackets andsteel or concrete. Where it is not possible for a worker to keep a safe distancefrom such earthed metal, insulating covers shall be applied to it.

Guide to Live LV Electrical Work (March 2005)

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Transcript of Guide to Live LV Electrical Work (March 2005)