Electrical safety, risk control and safe work practices
Risk management
Work through the hierarchy of control rather than reaching for PPE first. The best control for electrical risk is elimination: de-energise, isolate, lock and tag, then prove dead. Substitution and engineering controls follow (extra-low voltage, isolating transformers, barriers, insulated shrouds, RCDs on construction sites under AS/NZS 3012). Administrative controls - procedures, permits, signage, training and supervision - come next, and personal protective equipment is the last line of defence only.
Safe isolation
Identify every source: mains, solar PV, generators, UPS and battery systems, capacitors, control and backfeed circuits. Isolate, lock and tag with a personal lock and danger tag, prove the tester on a known source, test for absence of voltage at the point of work on every conductor, then prove the tester again. Treat everything as live until proved dead. AS/NZS 4836 sets the requirements for safe working on low-voltage installations; live work is acceptable only where it is justified, risk-assessed, authorised and carried out by competent people with suitable tools, equipment and PPE.
Traps
Using PPE as the primary control. Assuming a wall switch isolates everything, when it may be single-pole or mislabelled. Forgetting PV or generator backfeed. Testing with an unproved tester. Doing live work because isolation is inconvenient - exam questions usually want isolate and prove dead, not wear gloves.
Worked example
Rule of thumb: prove, test, prove. Before touching a conductor, prove the tester, test the conductor, and prove the tester again. If any one of those three steps is missing, the conductor must still be treated as live. If someone is in contact with live parts, isolate before touching them, then give first aid and call 000.