Frequently Asked Questions
The precise interval between tests depends on the type of equipment and the environment in which it is stored and/or used. On building sites testing may be carried out as often as every three months, whereas office equipment may be left for much longer periods, such as two years. Most laboratory and workshop equipment is tested annually.
Persons using electrical equipment should be encouraged to inspect the equipment visually at regular intervals (while it is not connected to the power supply) to look for:
- signs of damage (apart from light scuffing) to the cable sheath,
- damage to the plug
- a cable which is not adequately secured where it enters the plug, as evidenced by looseness, or the colour coded wires becoming visible.
- Inadequate joints in the cable,
- Evidence of overheating
- Damage to the external case of the machine
The discovery of any faults should result in the equipment being immediately taken out of service pending repair.
Formal testing of electrical appliances should include testing of the insulation between the live parts and earth, and (in equipment that is earthed) checking the earth loop resistance.
The requirement for such inspection and testing arise in the UK as a result of the Electricity at Work Regulations 1989, and further guidance is contained in the Health and Safety Executive Guidance Note HS(G) 107.