Electrical Safety and Hazard Awareness
Core concepts
Safety questions test understanding of shock hazards (current path, duration, body resistance), arc flash and blast, and the hierarchy of controls: elimination, substitution, engineering controls, administrative controls, and PPE. Know NFPA 70E concepts: incident energy, arc flash boundary, approach boundaries (limited, restricted), energized work permits, and PPE categories. Understand lockout/tagout, test-before-touch, temporary protective grounds, and the role of the qualified person. Recognize hazards from stored energy, backfeeds, and capacitive/inductive kickback.
Traps
Questions often confuse approach boundaries with the arc flash boundary, or assume PPE substitutes for de-energizing. Remember that de-energizing and verifying absence of voltage is always preferred; energized work requires justification. Another trap: assuming rubber gloves alone protect against arc flash-they protect against shock, not thermal energy. Also watch for the misconception that low voltage is harmless.
Worked example
Before working on a 480 V panel: de-energize, lock out, test with a meter rated for the voltage (CAT III/IV as appropriate), verify the tester on a known source before and after, then apply temporary grounds if required. Only then proceed.
Rule of thumb
Treat every conductor as energized until tested and grounded; test your tester before and after every absence-of-voltage check.