Electrical testing and certification are critical stages in building services installation. Testing verifies that circuits are safe before being energised and handed over. Incorrect testing procedures can result in electric shock, arc flash injuries, or systems being energised with undetected faults. This talk covers the safety requirements for electrical testing on UK construction sites.
Key Hazards
Electric shock during testing of live or partially live circuits
Arc flash burns from short circuits during insulation testing
Incorrect test results leading to unsafe circuits being energised
Damage to sensitive equipment from incorrect test voltage selection
Control Measures
Ensure only competent electricians with appropriate qualifications carry out testing.
Confirm all circuits are isolated and locked off before commencing dead testing.
Use calibrated test instruments with valid certification within their service date.
Wear appropriate PPE including insulated gloves and safety glasses during live testing.
Follow the correct testing sequence: continuity, insulation resistance, polarity, then earth fault loop.
Warn all nearby operatives before carrying out insulation resistance testing.
Record all test results accurately on the correct BS 7671 certification forms.
Verify test instrument leads are in good condition with no damaged insulation.
Never energise a circuit until all test results are confirmed satisfactory.
Emergency / Rescue
If an electric shock occurs during testing, isolate the supply immediately. Do not touch the casualty until the circuit is confirmed dead. Call 999 and begin CPR if the casualty is not breathing.
Remember
Only qualified and competent electricians may carry out testing and certification
Always isolate and lock off circuits before starting dead testing procedures
Use calibrated instruments that are within their valid service date
Follow the correct sequence of tests as required by BS 7671
Never energise any circuit until all test results are confirmed satisfactory
Record all results accurately on the correct certification documentation
Applicable Legislation: Electricity at Work Regulations 1989 · BS 7671 (IET Wiring Regulations) · Health and Safety at Work etc. Act 1974 · PUWER 1998