Practical Assessment and Safe Working
Safe working
Practical assessment tests whether you can work safely as well as technically. The core principle is test before touch: identify the circuit, isolate it, lock and tag, prove the tester on a known source, test the conductors, then re-prove the tester. Apply AS/NZS 4836 for low-voltage safe working and NZECP 34 for minimum safe distances from overhead lines and other services. Complete a risk assessment before work and use appropriate PPE, barricades and signage. Understand arc flash and the difference between shock protection and arc protection. Know emergency response: rescue without endangering yourself, CPR and first aid, and how to isolate the supply.
Traps
Trusting a switch position or a label instead of proving dead. Using a multimeter that has not been proved on a known live source. Assuming an RCD makes live work acceptable. Working alone on live equipment. Forgetting secondary hazards: stored energy, capacitors, backfeed from generators or PV, earthed metalwork, wet floors, ladders near lines. Treating a "dead" circuit as safe without testing between all conductors and earth.
Worked example
Proving dead: first test the tester on a known live source; second, test phase-to-neutral, phase-to-earth and neutral-to-earth at the point of work; third, re-test the tester on the known source. If any step is skipped, the isolation is unproven. Rule: prove, test, prove, and treat every conductor as live until proven otherwise.