Guidance on the Management of Electrical Safety and Safe Isolation Procedures for Low Voltage Installations

8/13/2019 Guidance on the Management of Electrical Safety and Safe Isolation Procedures for Low Voltage Installations

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Guidance on themanagement of electrical safety andsafe isolationprocedures for lowvoltage installations

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This is one of a series of Best Practice Guides produced bythe Electrical Safety Council* in association with leadingindustry bodies for the benefit of electrical contractors andinstallers, and their customers.

The Electrical Safety Council is indebted to the following

organisations for their contribution and/or support to thedevelopment and revision of this Guide, and in particular toSELECT and the HSE for providing the initial draft:

Published by:The Electrical Safety Council18 Buckingham Gate

LondonSW1E 6LB

Tel: 0870 040 0561 Fax: 0870 040 0560Email: bpg@esc .org.ukWebsite: www.esc .org.uk

The Electrical Safety Council and other contributors believe that theguidance and information contained in this Best Practice Guide iscorrect, but all parties must rely on their own skill and judgement whenmaking use of it. Neither the Electrical Safety Council nor any contributorassumes any liability to anyone for any loss or damage caused by anyerror or omission in this Guide, whether such error or omission is theresult of negligence or any other cause. Where reference is made tolegislation, it is not to be considered as legal advice. Any and all suchliability is disclaimed.

The Electrical Safety Council. September 2009

In electronic format, this Guide is intended to be made available free ofcharge to all interested parties. Further copies may be downloaded fromthe websites of some of the contributing organisations.

The version of this Guide on the Electrical Safety Council website(www.esc.org.uk ) will always be the latest. Feedback on any of the BestPractice Guides is always welcome email [email protected]

The Electrical Safety Council is supported by all sectors of the electricalindustry, approvals and research bodies, consumer interestorganisations, the electrical distribution industry, professional institutesand institutions, regulatory bodies, trade and industry associations andfederations, trade unions, and local and central government.

*The Electrical Safety Council (formerly the National Inspection Council

for Electrical Installation Contracting) is a charitable non-profit makingorganisation set up in 1956 to protect users of electricity against thehazards of unsafe and unsound electrical installations.

BEAMAwww.beama.org.uk

BSIwww.bsigroup.com

City & Guildswww.cityandguilds.com

Electrical Contractors Associationwww.eca.co.uk

ELECSAelecsa.org.uk

HSEwww.hse.gov.uk

Institution of Engineering andTechnologywww.theiet.org

NAPITwww.napit.org.uk

NICEIC Group Ltdwww.niceic.com

SELECT(Electrical ContractorsAssociation of Scotland)www.select.org.uk


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Introduction

This Best Practice Guide explains what needs to bedone to make sure workers on site are not exposedto danger when working on or near live electricalsystems and equipment in buildings, particularly inthe final stages of construction.

Every year, people working on construction sites and

on refurbishment and maintenance activities sufferelectric shock and burn injuries some of which,

tragically, are fatal. Electrical contractors should beaware that many of these accidents are a directconsequence of electricians not implementing safeisolation procedures on low voltage installations(that is, those operating at up to 1000 V a.c. or1500 V d.c.).

An example of one such fatal incident is given onthe following page.

page 3The Electrical Safety Council

Guidance on the managementof electrical safety andsafe isolation procedures forlow voltage installations

This Best Practice Guide has been produced in conjunction with the Healthand Safety Executive (HSE). Its purpose is to provide practical guidance foremployers, employees and the self-employed on the management of electrical safety, with particular emphasis on low voltage safe isolationprocedures to be followed during construction and refurbishment projects,and during maintenance activities.

The guidance is aimed at protecting employees and other workers againstserious or fatal electrical injuries. Although the principles apply generally,the guidance is particularly relevant to circumstances where work is beingcarried out in the presence of other trades, and to sites where more thanone electrician is employed.


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Experience shows that electricians employed byelectrical contractors are particularly at risk of deathor serious injury from electric shock or burns if theyfail to follow safe working procedures. To achieve

compliance with the legislation explained in thisGuide, electrical contractors should not allow orcondone dangerous work practices and shouldarrange for the safe working practices explained inthe Guide to be implemented diligently.

Whereas this Guide is aimed primarily at electricalcontractors and their employees, principalcontractors and non-electrical subcontractors have a

significant role in managing electrical risks duringconstruction and refurbishment projects. Principalcontractors and their non-electrical subcontractorsshould make themselves familiar with this Guide toensure, firstly, that they do not place electricalcontractors under pressure to implement unsafepractices; and, secondly, that they understand howtheir own employees may achieve safety fromelectrical risks.

Legislation

The Health and Safety atWork etc. Act 1974 sets outthe general health and safetyduties of employers,employees and the self-employed. The Electricity atWork Regulations 1989 , whichwere made under the Act,require precautions to betaken against the risk of death or personal injuryfrom electricity in work activities.

Duties are placed on employers to ensure, amongstother things, that employees engaged in such workactivities on or near electrical equipment* implementsafe systems of work, have the technical knowledge,training or experience to carry out the work safely,and are provided with suitable tools, test equipmentand personal protective equipment appropriate tothe work they are required to carry out.

page 4 The Electrical Safety Council

An electrician working on a new-buildconstruction project installed thethree-phase and neutral distributionboard shown in the photograph. He

energised the supply to thedistribution board before the circuitsconnected to it were complete, toprovide a supply to a socket-outlet.

He was connecting the supply cablesto a wall-mounted timer unit, with theline conductor connected to thecircuit-breaker at the top left hand sideof the busbar assembly. The circuit-

breaker had not been securely isolatedand was ON as he stripped the

insulation from the end of the cable.He touched the live copper conductorof the cable and was electrocuted.

The distribution board wasmanufactured to a high standard ofsafety. However, if he needed toenergise the board before it wascomplete, he should first have replacedthe cover and switched off and lockedthe circuit-breakers supplyingunfinished or incomplete circuits. Heshould also have ensured that circuitswere not connected into circuit

breakers until they were complete andhad been tested.

*The definition of electrical equipment is very broad, including anything used or intended to be used or installed for use, to generate, provide, transmit, transform, rectify, convert, conduct, distribute, control, store, measure, or use electrical energy.


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Under the Health and Safety at Work etc Act ,employees are required to co-operate with theiremployer to enable the requirements of theregulations to be met. This includes complying withany instructions given on matters such as safesystems of work. The Electricity at Work Regulations1989 require that employees themselves complywith the regulations.

The Management of Health and Safety at WorkRegulations 1999 require employers to make asuitable and sufficient assessment of the risks to thehealth and safety both of their employees and ofother persons arising out of, or in connection with,

the conduct of their undertakings. Where five ormore persons are employed, the employer mustrecord the significant findings of these riskassessments.

HSE Guidance

Generic guidance on safeworking practices for work onelectrical equipment ispublished by the Health andSafety Executive (HSE) in itsguidance note entitledElectricity at Work SafeWorking Practices (HSG85).

It provides information on dead and live workingand on isolation procedures when working on bothLow Voltage (LV) and High Voltage (HV) systems.This Best Practice Guide covers LV systems only andis targeted at the work of electrical contractors,particularly in the construction sector. Extraprecautions need to be taken when working with HVequipment and circuits, and reference should bemade to the detailed guidance provided in HSG85 insuch circumstances.

The Memorandum of Guidance on the Electricity atWork Regulations 1989 HSR(25) is intended to helpduty holders meet the requirements of theregulations. It will be of interest and practical helpprimarily to engineers, technicians and theirmanagers (including those involved in the design,construction, operation or maintenance of electricalsystems and equipment).

It sets out the regulations and gives technical andlegal guidance on the regulations. Its purpose is toamplify the nature of the precautions in generalterms so as to help in the achievement of highstandards of electrical safety in compliance with the

duties imposed.

In the context of risks arising from live work,regulation 14 of the Electricity at Work Regulations1989 requires that:

No person shall be engaged in any work activity onor so near any live conductor (other than onesuitably covered with insulating material so as to

prevent danger) that danger may arise unless

(a) it is unreasonable in all the circumstances for itto be dead; and

(b) it is reasonable in all the circumstances for himto be at work on or near it while it is live; and

(c) suitable precautions (including where necessary

the provision of suitable protective equipment)are taken to prevent injury.

It should be noted that all three conditionsmust be met in order for work on or near liveconductors to be carried out.



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To comply with regulation 14 of the Electricity atWork Regulations 1989 (work on or near liveconductors), dead working should be the normalmethod of carrying out work on electrical equipmentand circuits.

Live working, which includes not only working on liveuninsulated conductors but also working so near liveuninsulated conductors that there is a risk of injury,should only be carried out in circumstances where itis unreasonable to work dead.

Typically this would include some types of faultfinding and testing (including the live testing

requirements of BS 7671 Requirements for Electrical Installations (IEE Wiring Regulations) ), butonly where the risks are acceptable and wheresuitable precautions are taken against injury,including the provision of adequate training andpersonal protective equipment (PPE).

Pressure to carry out live work is becoming morecommon in areas such as construction sites, high

cost manufacturing and in retail outlets operatingtwenty-four hours per day, seven days a week.

Irrespective of these pressures, the requirements ofthe regulations still apply in such situations and liveworking should only be carried out when justifiedusing the criteria explained in HSG85.

For systems where the supply has been cut off to

allow dead working, regulation 13 of the Electricity at Work Regulations 1989 applies as follows:

Adequate precautions shall be taken to preventelectrical equipment, which has been made dead inorder to prevent danger while work is carried out onor near that equipment, from becoming electrically charged during that work if danger may thereby arise.

This regulation therefore requires that adequateprecautions are taken to ensure that conductors andequipment cannot inadvertently be energised whilethe work is taking place this is the process ofisolation.

The Electricity at Work Regulations 1989 definitionof isolation is given in regulation 12 and meansthe disconnection and separation of the electrical equipment from every source of electrical energy insuch a way that this disconnection and separation issecure.

In effect this means not just cutting off the supply

but also ensuring that the means of disconnection issecure, as described in this Guide. In most instancesthis will require securing the means of disconnectionin the OFF position and it is highly recommendedthat a caution notice or label is posted at the pointof disconnection as described in the Guide underSafe isolation procedures .

Of equal importance is regulation 16. This requires

that employers ensure that all employees involved inwork on electrical equipment are competent.

Employees should be instructed on, and trained in,the implementation of safe systems of work. If theyhave not received such training and instruction, theyshould only work under the supervision of acompetent person.



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Site safety management

It is essential from the outset that effectivemanagement and control of the working practices

on electrical systems and equipment, particularly inrelation to safe isolation procedures, are establishedand maintained.

It should be noted that although this Guide is mainlyaimed at construction sites, the general principles ofmanagement and control also apply to all electricalinstallation work including refurbishment andmaintenance activities.

Directors and managers of companies employingelectrical operatives should ensure that theirrequirements for safe working practices are clearlyexplained in company-specific electrical safety policydocuments including site-specific risk assessmentsand method statements.

Guidance on how to carry out risk assessments andthe form they should take is published by the HSE on

its website at www.hse.gov.uk/risk/index.htm

All operatives should be shown these documents andhave the contents including their responsibilitiesclearly explained. This can be done during siteinductions and/or regular tool-box talks.

Managers should ensure that operatives understandthe information regarding safe working practices,

particularly where they may not have a goodcommand of English.

It is very important for managers to ensure thatthese safety management documents are regularlyreviewed. They should be updated as required if andwhen the risks change significantly, particularlyduring the period of a specific contract.

Directors and managers are expected to involvethemselves in, and show visible and positiveleadership in, the management of every aspect ofhealth and safety on their sites.

Guidance on the roles and responsibilities ofdirectors and managers is given in guidance leafletLeading Health and Safety at Work (INDG417). Thisis a joint publication of the Institute of Directors andHSE, It is available at www.hse.gov.uk/leadership

Managers should also ensure that their operativesare provided with all the tools, suitable testequipment, personal protective equipment, lockingclips, padlocks, keys and caution and danger noticesidentified in their risk assessments and methodstatements.

National Working Rule C2.4 in the Scottish Joint

Industry Board (SJIB) handbook (2008 to 2011)requires operatives to provide particular tools andtest equipment, including a proprietary test lamp orvoltage detector.

The same rule requires employers to carry outperiodic tool kit inspections to ensure that theiremployees are in possession of all the items listed inthe handbook and they are of suitable quality and in

good repair.

For projects where work is being carried out in thepresence of other trades, and sites involving morethan one electrical operative, it is essential that asuitably experienced and competent person isappointed to oversee the work on site during theconstruction of the electrical installation.

This appointed persons responsibilities shouldinclude the overseeing of the working practices ofthe operative(s) to ensure that they consistently anddiligently follow the practices set out in the riskassessments and method statements.

They may also be given responsibility for controllingthe work of appointed sub-contractors, who mustprovide appropriate method statements and riskassessments for their work.



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Energised plant

Exposed cables which are liable to be damagedby other trades or the environmental conditions.

People entering completed and energised areasworking under instructions from the principalcontractor or clients representative must be madeaware of the extent of the live services within therespective areas by the electrical contractor, principalcontractor or clients representative. They shouldassume that all services within such areas areenergised.

The electrical contractor must inform the principalcontractor when they intend to complete andenergise the electrical installation in an area. Theprincipal contractor must then ensure that theclients representative and all persons on site areinformed that the electrical installation in that areahas been energised.

All contractors should advise their employees of this

fact at appropriate site inductions and toolbox talks.

Safe isolation procedures

For all work on LV electrical equipment or circuits, it isimportant to ensure that the correct point of

isolation is identified, that an appropriate means ofisolation is used, and that the supply cannotinadvertently be reinstated while the work is inprogress. The conductors must be proved to be deadat the point of work before they are touched andwhere necessary caution notices should also beapplied at the point(s) of isolation.

In the interests of avoiding inadvertent energisation,a good principle to adopt is that the point ofisolation should be under the control of the personwho is carrying out the work on the isolatedconductors.

If alternative means of controlling the security of theisolation are adopted, such as the point of isolationbeing kept under the control of an appointed(authorised) person, these means should be equallyeffective at preventing inadvertent reinstatement of

the supply.

The means of isolation can be an adjacent localisolation device such as a plug and socket-outlet,fused connection unit, switch-disconnector, circuit-breaker, fuse etc, as appropriate, which is under thedirect control of the competent person carrying outthe work.

When isolating the main source of energy, it isalso essential to isolate any secondary sources(such as standby generators, uninterruptiblepower supplies and microgenerators).

A comprehensive list of devices that can be used forisolation is given in Table 53.2 of BS 7671: 2008.

These devices can be used without furtherprecautions provided there is no foreseeable risk thatthe supply could be reinstated by others prior to thework being completed by the competent person.



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Note:Circuit-breakers conforming to BS EN 60898 aresuitable for isolation and may be marked with thefollowing symbol:

However, miniature circuit-breakers (MCBs)manufactured to earlier standards (such as BS 3871)are unlikely to be suitable for isolation.

Switchgear conforming to BS EN 60947-3 andcircuit-breakers and RCDs conforming toBS EN 60947-2 are suitable for isolation if markedwith the symbol shown above.

See Annex 1 for further guidance on theidentification of devices suitable for isolation.

Where there is no such local means of isolationor where there is a risk of reinstatement of thesupply, the circuit or equipment to be worked onshould be securely isolated by one of thefollowing methods

Isolation using a main switch or distributionboard switch-disconnector

Isolation of equipment or circuits using the mainswitch or distribution board switch-disconnector isthe preferred method. The point of isolation shouldbe locked off using a unique key or combinationretained by the person carrying out the work or theappointed person, and a caution notice attached to

the point of isolation.

Where more than one operative is working oncircuits supplied from an isolated distribution board,a multi-lock hasp can be used to prevent operationof the main isolator until such time that all personsworking on the installation have completed theirwork and removed their padlocks from the hasp.

If locking-off facilities are not provided on therelevant switch, then a locked distribution boardwhich prevents access to the switch-disconnector isacceptable provided the key or combination isunique and is retained by the person doing the workor the appointed person.

Again, multi-lock hasps can be used to control theisolation where more than one person is working onthe installation. An alternative to a multi-lock hasp isa key box or similar system which provides effectivecontrol of access to the key for the point of isolation.

Isolation of individual circuits

Where it is intended that more than one person willbe working on circuits supplied from a distributionboard (that is, multiple isolations) and a multi-lockhasp cannot be used to secure the main switch-disconnector or the distribution board has to remainenergised to supply other circuits, each circuitsupplied from the distribution board on which workis to be carried out should be isolated by one ormore of the following methods to preventinadvertent reinstatement of the supply.


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The principle is that each person carrying out suchwork should have control of their own point(s) ofisolation and not rely on others, except an appointedperson, to prevent deliberate or inadvertentenergisation.

It is preferable that a final circuit distributionboard is not energised until all of its final circuitshave been completed, and inspected and tested.

It is also preferable for an appropriate locking-offdevice to be used at the point(s) of isolation.However, if any items required for carrying out theprocedures recommended below are not

manufactured for the distribution board in questionor cannot be obtained through retail/trade outlets, itis acceptable to disconnect the circuit from thedistribution board provided the disconnectedconductors are made safe by being coiled and theconductors insulated or otherwise protected againstinadvertent re-energisation.

Suitable labelling of the disconnected conductors

using a caution notice is vital to prevent the supplybeing reinstated, particularly if other electricians arepresent.

Work carried out inside a live distribution board, suchas disconnecting a circuit for isolation, is classed aslive working when there is access to exposed liveconductors. In this case, the appropriate precautionsshould be taken as described in HSG85 with respect

to regulation 14 of the Electricity at WorkRegulations.

1. Isolation of individual circuits protected bycircuit-breakers

Where suitable circuit-breakers are used as themeans of isolation, the relevant device should belocked-off using an appropriate locking-off clip witha padlock which can be opened only by a unique key

or combination. The key or combination should beretained by the person carrying out the work or theappointed person. A caution notice should beattached at the point of isolation.

The practice of placing insulating tape over acircuit-breaker to prevent inadvertent switch-onis not an adequate or acceptable means of securing the device in the OFF position. Suchunsafe practice will not achieve compliance with

the Electricity at Work Regulations 1989 .


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Note: Some distribution boards are manufacturedwith slider switches to disconnect the circuit fromthe live side of the circuit breaker. These devicesshould not be relied upon as the only means ofisolation for circuits, as they do not meet therequirements for isolation and the wrong switchcould easily be operated on completion of the work.

2. Isolation of individual circuits protected by fuses

Where fuses are used, the removal of the fuse is anacceptable means of disconnecting the supply to anindividual circuit for the purpose of isolation.

To prevent the fuse being replaced by others, the fuseshould be retained by the person carrying out thework, and a lockable fuse insert with a padlock shouldbe fitted to achieve secure isolation. A caution noticeshould be attached at the point of isolation.

Where lockable fuse inserts are not available, thefollowing must be considered:

Where removal of the fuse exposes liveterminals that can be touched, a dummy fuse(that is a fuse carrier which is not fitted with afuse link and which is clearly marked or colouredto make it conspicuous) should be inserted inthe fuse way to cover live parts. When this is notpossible, the incoming supply to the fuse willneed to be isolated

A caution notice should be attached to deterinadvertent replacement of a spare fuse

In addition, if possible, the fuseboard door orcover should be locked to prevent access asadvised above under Isolation using a mainswitch or distribution board switch-disconnector.

Temporary disconnection of the incomingsupply

For some types of work on existing installations, suchas the replacement of main switchgear andconsumer units, it is necessary for the distributorsservice fuses to be withdrawn in order to disconnectthe incoming supply for the purpose of isolation.

Legally, service fuses can be withdrawn only by theelectricity supplier or distributor, or by those theyhave expressly authorised to carry out such work.

Note: In TT systems, the incoming neutralconductor cannot reliably be regarded as beingat Earth potential. This means that for TTsupplies, a multi-pole switching device which

disconnects the line and neutral conductorsmust be used as the means of isolation. Forsimilar reasons, in IT systems, all poles of thesupply must be disconnected.

In these circumstances, single pole isolation,such as by fuses or single-pole circuit-breakers, isnot acceptable.

Electrical permits-to-work

An electrical permit-to-work must be used for workon HV systems that have been made dead, and canbe useful in certain situations for LV work, such aswhere there is more than one source of supply.

These permits are primarily a statement that acircuit or item of equipment is isolated and has been

made safe to work on. They must not be used for liveworking as this can cause confusion.

Details on the use of these permits, including anexample form, are given in HSG85.



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Caution notices

In all instances where there is any risk that thesupply could be reinstated, an appropriate

warning/caution notice should be placed at thepoint of isolation. For distribution boards withmultiple isolations, a single suitably worded noticeon each distribution board, such as the exampleshown below, would suffice:

Proving dead isolated equipment orcircuits

It is important to ensure that the correct point

of isolation is identified before proving dead.

Where possible and safe to do so, this may includetesting with the isolating device first in the ONposition and then in the OFF position to establishthat the equipment or circuit is under the control ofthat device.

Following isolation of equipment or circuits andbefore starting work it should be proved that theparts to be worked on, and those nearby, are dead.

It should never be assumed that equipment isdead because a particular isolation device has beenplaced in the OFF position.

The procedure for proving dead should be by use ofa proprietary test lamp or two-pole voltage detectoras recommended in HSE Guidance Note GS38,

Electrical test equipment for use by electricians .

The use of multimeters, makeshift devices and non-contact voltage indicators (voltage sticks) is notadvised for voltage detection as such use has causedaccidents.


Example of a warning notice

CAUTIONTHIS DISTRIBUTION BOARD HAS A NUMBER

OF CIRCUITS THAT ARE SEPARATELYISOLATED. PRIOR TO REINSTATING THE

SUPPLY TO AN INDIVIDUAL CIRCUIT, CARESHOULD BE TAKEN TO ENSURE THAT IT IS

SAFE TO DO SO.

Typical devices for proving dead


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The test lamp or voltage detector should be provedto be working on a known live source, proprietaryproving unit or in-built test feature before and afteruse. All line, neutral and protective conductors of thecircuit should be tested and proved to be dead.

Electricians who regularly work on installations thathave been energised should be equipped withdevices for proving that conductors are dead.

Electricians who may occasionally work oninstallations that have been energised should haveready access to devices for proving conductors dead.

Additional precautions

New installationsNew installations can be a particular hazard as some

of the circuits or equipment may require to bemodified after the installation has been energised.

It is therefore important that every protective deviceis correctly identified at each distribution boardbefore any energising takes place, and safe isolationprocedures, such as locking-off circuit breakers asdescribed above, are adopted, particularly where anumber of electricians are working on the sameinstallation.

Alterations and additionsAlterations and additions to existing installations canalso be particularly hazardous. Records includingcircuit identification may not be available, or may beinadequate or incorrect. It is therefore particularlyimportant to ensure that circuits to be worked onhave been correctly identified for isolation purposes

prior to work commencing.

Circuits under automatic controlIt is particularly important to correctly identifycircuits for isolation purposes if they are underautomatic control, such as by time switch orphotocell.

Deaths and injuries have occurred where circuitshave been proved to be dead at the point of workbefore work commenced, only for the circuits to beenergised unexpectedly by automatic controls aswork was underway.



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DEVICE STANDARD SUITABLE FOR ISOLATION+

Switching device BS 3676: Part 1: 1989 Yes***

BS EN 60669-1 NoBS EN 60669-2-1 NoBS EN 60669-2-2 NoBS EN 60669-2-3 NoBS EN 60669-2-4 YesBS EN 60947-3 Yes*BS EN 60947-5-1 No

Contactor BS EN 60947-4-1 Yes*BSEN 61O95 No

Circuit-breaker BS 3871 NoBS EN 60898 Yes

BS EN 6094 7-2 Yes*BS EN 61009-1 Yes

RCD BS 4293 NoBS EN 60947-2 Yes*BS EN 61008-1 YesBS EN 61009-I Yes

Isolating switch BS EN 60669-2-4 YesBS EN 60947-3 Yes

Plug and socket-outlet < 32 A BS EN 60309 YesIEC 60884 Yes

IEC 60906 Yes

Plug and socket-outlet > 32 A BS EN 60309 Yes

Device for the connection of luminaire BS IEC 61995-1 Yes**

Control and protective switching BS EN 60947-6-1 Yesdevice for equipment (CPS) BS EN 60947-6-2 Yes*

Fuse BS 88 Yes

Device with semiconductors BS EN 60669-2-I No

Luminaire supporting coupler BS 6972 Yes**

Plug and unswitched socket-outlet BS 1363-1 Yes**BS 1363-2 Yes**

Plug and switched socket-outlet BS 1363-I Yes**BS 1363-2 Yes**

Plug and socket-outlet BS 5733 Yes**

Switched fused connection unit BS 1363-4 Yes**

Unswitched fused connection unit BS 1363-4 Yes** (Removal of fuse link)

Fuse BS 1362 Yes

Cooker Control Unit switch BS 4177 Yes

+ In an installation forming part of a TT or IT system, isolation requires disconnection of all the live conductors* Isolation provided if the device is suitable and marked with the symbol for isolation** Device is suitable for on-load isolation, that is disconnection whilst carrying load current*** Isolation provided if the device is suitable and marked with

Annex 1 - Identification of devices suitable for isolationTable based on Table 53.2 of BS 7671: 2008 (as corrected), by kind permission of the Institution of Engineering and Technology.


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Annex 3 - Quick Guide to Safe Isolation Procedure

NICEIC Pocket Guide No 5Copies of this and other NICEIC Pocket Guides may be downloaded from www.niceic.com

Alternatively email [email protected] or telephone 0870 013 0382


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Annex 4

Double-sided safe isolation warning flag and sticker available free of charge from:

The Institution of Engineering and Technology , PO Box 96, Stevenage, Herts, SG1 2SD.


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The latest versions of all the BestPractice Guidesare avalable to download from www. esc .org.uk

Documents

Guidance on the Management of Electrical Safety and Safe Isolation Procedures for Low Voltage Installations