Electrical safety - H&S at work

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.

Main hazards

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.
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.

Risk Reduction

Where possible reduce the voltage/ use earth leakage protection devices;
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
choose equipment that is suitable for its working environment;
electrical risks can sometimes be eliminated by using air, hydraulic or hand-powered 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 light bulbs 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;
if possible connect equipment at 230V through residual current device which cuts the current off rapidly if a fault occurs.

Underground power cables

Always assume cables will be present when digging in the street, pavement or near buildings.

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 about the safe working distance from the cables.