general safety for electricity

Electrical
safety
and you
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INTRODUCTION
Electricity can kill. Each year about 1000 accidents at work involving electric shock
or burns are reported to the Health and Safety Executive (HSE). Around 30 of
these are fatal. Most of these fatalities arise from contact with overhead or
underground power cables.
Even non-fatal shocks can cause severe and permanent injury. Shocks from faulty
equipment may lead to falls from ladders, scaffolds or other work platforms.
Those using electricity may not be the only ones at risk: poor electrical
installations and faulty electrical appliances can lead to fires which may also cause
death or injury to others. Most of these accidents can be avoided by careful
planning and straightforward precautions.
This leaflet outlines basic measures to help you control the risks from your use of
electricity at work. More detailed guidance for particular industries or subjects is
listed on pages 6 - 8. If in doubt about safety matters or your legal responsibilities,
contact your local inspector of health and safety. The telephone number of your
local HSE office will be in the phone book under Health and Safety Executive. For
premises inspected by local authorities the contact point is likely to be the
environmental health department at your local council.
WHAT ARE THE HAZARDS?
The main hazards are:
■ contact with live parts causing shock and burns (normal mains voltage,
230 volts AC, can kill);
■ faults which could cause fires;
■ fire or explosion where electricity could be the source of ignition in a
potentially flammable or explosive atmosphere, eg in a spray paint booth.
ASSESSING THE RISK
Hazard means anything which can cause harm.
Risk is the chance, great or small, that someone will actually be harmed by the
hazard.
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The first stage in controlling risk is to carry out a risk assessment in order to
identify what needs to be done. (This is a legal requirement for all risks at work.)
When carrying out a risk assessment:
■ identify the hazards;
■ decide who might be harmed, and how;
■ evaluate the risks arising from the hazards and decide whether existing
precautions are adequate or more should be taken;
■ if you have five or more employees, record any significant findings;
■ review your assessment from time to time and revise it if necessary.
The risk of injury from electricity is strongly linked to where and how it is used.
The risks are greatest in harsh conditions, for example:
■ in wet surroundings - unsuitable equipment can easily become live and
can make its surroundings live;
■ out of doors - equipment may not only become wet but may be at
greater risk of damage;
■ in cramped spaces with a lot of earthed metalwork, such as inside a tank
or bin - if an electrical fault developed it could be very difficult to avoid
a shock.
Some items of equipment can also involve greater risk than others. Extension
leads are particularly liable to damage - to their plugs and sockets, to their
electrical connections, and to the cable itself. Other flexible leads, particularly
those connected to equipment which is moved a great deal, can suffer from
similar problems.
More information on carrying out risk assessments is available in other HSE
publications listed on page 6 of this leaflet.
REDUCING THE RISK
Once you have completed the risk assessment, you can use your findings to
reduce unacceptable risks from the electrical equipment in your place of work.
There are many things you can do to achieve this; here are some.
Ensure that the electrical installation is safe
■ install new electrical systems to a suitable standard, eg BS 7671 Requirements
for electrical installations, and then maintain them in a safe condition;
■ existing installations should also be properly maintained;
■ provide enough socket-outlets - overloading socket-outlets by using
adaptors can cause fires.
Provide safe and suitable equipment
■ choose equipment that is suitable for its working environment;
■ electrical risks can sometimes be eliminated by using air, hydraulic or handpowered
tools. These are especially useful in harsh conditions;
■ ensure that equipment is safe when supplied and then maintain it in a safe
condition;
■ provide an accessible and clearly identified switch near each fixed machine
to cut off power in an emergency;
■ for portable equipment, use socket-outlets which are close by so that
equipment can be easily disconnected in an emergency;
■ the ends of flexible cables should always have the outer sheath of the cable
firmly clamped to stop the wires (particularly the earth) pulling out of the
terminals;
■ replace damaged sections of cable completely;
■ use proper connectors or cable couplers to join lengths of cable. Do not
use strip connector blocks covered in insulating tape;
■ some types of equipment are double insulated. These are often marked with
a ‘double-square’ symbol . The supply leads have only two wires - live
(brown) and neutral (blue). Make sure they are properly connected if the
plug is not a moulded-on type;
■ protect lightbulbs and other equipment which could easily be damaged in
use. There is a risk of electric shock if they are broken;
■ electrical equipment used in flammable/explosive atmospheres should be
designed to stop it from causing ignition. You may need specialist advice.
Reduce the voltage
One of the best ways of reducing the risk of injury when using electrical equipment
is to limit the supply voltage to the lowest needed to get the job done, such as:
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4
■ temporary lighting can be run at lower voltages, eg 12, 25, 50 or 110 volts;
■ where electrically powered tools are used, battery operated are safest;
■ portable tools are readily available which are designed to be run from a
110 volts centre-tapped-to-earth supply.
Provide a safety device
If equipment operating at 230 volts or higher is used, an RCD (residual current
device) can provide additional safety. An RCD is a device which detects some, but
not all, faults in the electrical system and rapidly switches off the supply. The best
place for an RCD is built into the main switchboard or the socket-outlet, as this
means that the supply cables are permanently protected. If this is not possible a
plug incorporating an RCD, or a plug-in RCD adaptor, can also provide additional
safety.
RCDs for protecting people have a rated tripping current (sensitivity) of not more
than 30 milliamps (mA). Remember:
■ an RCD is a valuable safety device, never bypass it;
■ if the RCD trips, it is a sign there is a fault. Check the system before using it
again;
■ if the RCD trips frequently and no fault can be found in the system, consult
the manufacturer of the RCD;
■ the RCD has a test button to check that its mechanism is free and
functioning. Use this regularly.
Carry out preventative maintenance
All electrical equipment and installations should be maintained to prevent danger.
It is strongly recommended that this includes an appropriate system of visual
inspection and, where necessary, testing. By concentrating on a simple, inexpensive
system of looking for visible signs of damage or faults, most of the electrical risks
can be controlled. This will need to be backed up by testing as necessary.
It is recommended that fixed installations are inspected and tested periodically by
a competent person.
The frequency of inspections and any necessary testing will depend on the type of
equipment, how often it is used, and the environment in which it is used. Records
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of the results of inspection and testing can be useful in assessing the effectiveness
of the system. More detailed guidance is available in the booklets listed on pages
6 - 8.
Equipment users can help by reporting any damage or defects they find.
Work safely
Make sure that people who are working with electricity are competent to do the
job. Even simple tasks such as wiring a plug can lead to danger - ensure that people
know what they are doing before they start.
Check that:
■ suspect or faulty equipment is taken out of use, labelled ‘DO NOT USE’ and
kept secure until examined by a competent person;
■ where possible, tools and power socket-outlets are switched off before
plugging in or unplugging;
■ equipment is switched off and/or unplugged before cleaning or making
adjustments.
More complicated tasks, such as equipment repairs or alterations to an electrical
installation, should only be tackled by people with a knowledge of the risks and the
precautions needed.
You must not allow work on or near exposed live parts of equipment unless it is
absolutely unavoidable and suitable precautions have been taken to prevent injury,
both to the workers and to anyone else who may be in the area.
Underground power cables
Always assume cables will be present when digging in the street, pavement or near
buildings. Use up-to-date service plans, cable avoidance tools and safe digging
practice to avoid danger. Service plans should be available from regional electricity
companies, local authorities, highways authorities, etc.
Overhead power lines
When working near overhead lines, it may be possible to have them switched off if
the owners are given enough notice. If this cannot be done, consult the owners
6
about the safe working distance from the cables. Remember that electricity can
flash over from overhead lines even though plant and equipment do not touch
them. Over half of the fatal electrical accidents each year are caused by contact
with overhead lines. More detailed guidance on avoidance of danger from
overhead electric lines is available from HSE.
Electrified railways and tramways
If working near electrified railways or tramways, consult the line or track
operating company. Remember that some railways and tramways use electrified
rails rather than overhead cables.
HSE GUIDANCE ON ELECTRICAL SAFETY
The following publications contain advice on the safe use of electricity for
particular industries or in high risk circumstances.
Risk assessment and general health and safety
5 steps to risk assessment INDG163(rev1) HSE Books 1998 (single copies free
or priced packs of 10 ISBN 0 7176 1565 0)
Essentials of health and safety at work HSE Books 1994 ISBN 0 7176 0716 X
Maintenance of portable electrical equipment
Maintaining portable and transportable electrical equipment HSG107
HSE Books 1994 ISBN 0 7176 0715 1
Maintaining portable electrical equipment in offices and other low-risk environments
INDG236 HSE Books 1996 (single copies free or priced packs of 10
ISBN 0 7176 1272 4)
Maintaining portable electrical equipment in hotels and tourist accommodation
INDG237 HSE Books 1996 (single copies free or priced packs of 10
ISBN 0 7176 1273 2)
General electrical guidance
Avoiding danger from underground services HSG47 (Second edition)
HSE Books 2000 ISBN 0 7176 1774 0
Avoidance of danger from overhead electrical lines GS6(rev) HSE Books 1997
ISBN 0 7176 1348 8
Electrical safety on construction sites HSG141 HSE Books 1995
ISBN 0 7176 1000 4
Electricity at work - safe working practices HSG85 HSE Books 1993
ISBN 0 7176 0442 X
Electrical test equipment for use by electricians GS38(rev) HSE Books 1995
ISBN 0 7176 0845 X
Electrical safety at places of entertainment GS50 HSE Books 1997
ISBN 0 7176 1387 9
Electrical hazards from steam/water pressure cleaners etc PM29(rev)
HSE Books 1995 ISBN 0 7176 0813 1
Selection and use of electric handlamps PM38 HSE Books 1992
ISBN 0 11 886360 6
Memorandum of guidance on the Electricity at Work Regulations 1989 HSR25
HSE Books 1989 ISBN 0 7176 1602 9
GUIDANCE ON ELECTRICAL SAFETY FROM OTHER
ORGANISATIONS
Note: The inspection and testing intervals for electrical equipment given in these
publications are recommendations and are not legal requirements.
BS 7671: 2001 Requirements for electrical installations. IEE Wiring Regulations
16th edition. The IEE Wiring Regulations have the status of a British Standard.
They are supported by a separate series of Guidance Notes enlarging on
particular requirements of parts of the Regulations.
Code of practice for in-service inspection and testing of electrical equipment
Both titles are available from:
Institution of Electrical Engineers
PO Box 96
Stevenage, Herts SG1 2SD
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FURTHER INFORMATION
This leaflet is available in priced packs of 15 from HSE Books,
ISBN 0 7176 1207 4. Single free copies are also available from HSE Books.
HSE priced and free publications are available by mail order from HSE Books,
PO Box 1999, Sudbury, Suffolk CO10 2WA Tel: 01787 881165
Fax: 01787 313995 Website: www.hsebooks.co.uk (HSE priced publications are
also available from bookshops.)
For information about health and safety ring HSE's InfoLine Tel: 08701 545500
Fax: 02920 859260 e-mail: hseinformationservices@natbrit.com or write to
HSE Information Services, Caerphilly Business Park, Caerphilly CF83 3GG.
You can also visit HSE’s website: www.hse.gov.uk
This publication may be freely reproduced, except for advertising, endorsement or
commercial purposes. The information it contains is current at 3/98.
Please acknowledge the source as HSE.
Printed and published by the Health and Safety Executive
INDG231 Reprinted 11/03 C500
This leaflet contains notes on good practice which are not compulsory but which
you may find helpful in considering what you need to do.
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use by electricians GS38(rev)
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steam/water pressure
cleaners etc PM29(rev)
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