Working with Electricity
Working with Electricity
Electricity is dangerous – it can cause fires, serious injury and it can KILL.
The Electricity at Work Regulation is the main law covering electricity but BS 7671 for
installations is also significant. Former IEE Regulations.)
Working with electricity involves two distinct areas:
1 Doing electrical work, i.e. installations or repairs to an electrical system.
2 Using electrical appliances to lighten or speed up other types of work.
Understanding how electrical equipment is designed to be safe will help us to spot when
Something is wrong - therefore dangerous. For example,
- All metal parts designed to carry current (conductors) need to be properly insulated.
- If the insulation is vulnerable it has to be additionally protected – sheathing, conduit, trunking or armoured cable may be used.
- If you can see defective insulation or sheathing, the system is not as safe as it should be. The system should be isolated and immediate steps taken to get it repaired by a competent person. For example, a flex pulling out of a plug top or a cable frayed or split showing the colours inside.
NOTE: Sometimes conductors are made safe by ‘placing out of reach’. This is OK until unusual circumstances (perhaps maintenance or decorating work) make them not ‘out of reach’ any more. Take special care in such cases.
- Earthing all metal parts not intended to carry current will prevent them becoming live in a fault situation. Earth wires and connectors are just as important as the circuit wires. A competent person must repair any damage or looseness immediately.
- Earthing, works in conjunction with the fuse or circuit breaker to protect the circuit in the event of excessive current. If a wrong size fuse is fitted, or if a circuit breaker is tampered with, the protection may not be adequate and danger could arise.
- For the protection of people, either the voltage has to be reduced to a safe level by a transformer, or if using 240v, a Residual Current Device (RCD) should be used to limit the fault-current.
- When using 110v transformers the maximum voltage to earth is only 55v. An RCD limits the fault current to only 30mA and trips in less than half a second.
NOTE: RCD devices do not prevent electric shock –they only have the effect that the shock is unlikely to be fatal. In damp or sweaty conditions the shock could still be severe so do not be lulled into a false sense of security.
- If in doubt, have the circuit/equipment checked by an electrician before starting work.
For more information visit www.hse.gov.uk