Electrical Safety and Codes
Electrical Safety and Codes
This domain tests how you recognize electrical hazards, apply safe work procedures, and use code requirements as design and inspection criteria rather than memorized trivia. Expect questions on isolation, arc-flash and shock risk, bonding, clearances, and protective devices.
Core rules
- Treat every conductor as energized until it is isolated, locked, tagged, tested, and proven dead at the point of work.
- Use a documented risk assessment and correct PPE; arc-rated clothing does not replace de-energizing.
- Bonding and equipment grounding provide a low-impedance fault path; grounding electrodes are not the same as bonding.
- Maintain working space, guarding, labelling, and overcurrent protection required by the applicable code edition, such as NFPA 70, CSA C22.1, or IEC 60364 as adopted locally.
Worked example
A 480 V motor starter needs a terminal check. Identify all sources, including control circuits and backfeed. Open the disconnect, apply a personal lock and tag, test the tester on a known live source, then verify phase-to-phase, phase-to-ground, and phase-to-neutral. Retest the tester afterward. If another worker needs access, each person applies a personal lock. Re-energizing requires confirming everyone is clear and removing locks under the procedure.
Traps
Assuming a remote disconnect is the only source; using a non-contact tester as the sole dead check; sharing a lock; confusing equipment grounding with the neutral; ignoring arc-flash labels or DC control sources. Also watch for stored energy and capacitive charge.