Working with electricity

Electrocution is an ever-present hazard in workshops, when using power tools and machines, or when otherwise exposed to an electricity supply.

Managing hazards

Domestic scale applications are served by 1 phase supply (230v), whilst industrial situations may require 2 or 3 phase supply (400v).

• Fuses or circuit breakers are primary protection against electrical overload, although they also protect the user from gross electrical faults.
• A fuse or circuit breaker may break the circuit if it is overloaded. If after unplugging an appliance on the circuit, the circuit breaks again, an inspection by an electrician is necessary.

Earthing of appliances

In dry, indoor situations, earthing of appliances is achieved by the earth wire in the power cable. This is not sufficient protection for industrial and construction situations, where double insulation, Residual Current Devices, isolating, transformers or other safeguards are required.

• Double insulation appliances have insulation between exposed metal parts and the insulation of the current-carrying parts. These may be used in wet conditions, but supplementary protection (eg isolating transformer) is recommended as double insulation does not protect against faulty leads or plugs.
• Isolating transformers protect single phase portable electrical appliances. They must be located as close to the supply as possible, and each appliance requires a dedicated isolating transformer.
• Residual Current Devices (also called Earth Leakage Devices) detects faults in the circuit where electricity is leaking to earth, and automatically breaks the circuit.
• Monitored earth protection is used for two-phase supplies, and monitors circuit integrity using a low voltage current which detects when the earth connection is broken, and automatically breaks the circuit.

Emergency procedures

Electrocution - if possible, turn off the power source or disconnect the victim.

Do not touch the victim or any conducting material in the vicinity until this is done.