Safety
Foundation
The safety domain rewards candidates who can apply the hierarchy of controls rather than recite slogans. Know the sequence - elimination, substitution, engineering controls, administrative controls, then PPE last - and be ready to identify which level a given control belongs to. Understand the electrical-specific fundamentals: the shock hazard depends on current path and duration, not voltage alone; approach boundaries (limited, restricted) are set by voltage class; and equipotential grounding protects against differences in potential, not against contact with an energized conductor.
Concepts to master
Arc flash: incident energy rises with available fault current and clearing time, so faster protection and greater distance both reduce exposure. Personal protective equipment is rated by arc rating (cal/cm²), and the arc rating of a layered system is not the simple sum of the layers. Minimum approach distances, rubber glove classes and testing intervals, and the purpose of a tag-and-lock procedure all appear regularly. Also know the difference between a qualified and an unqualified person, and when an observer or standby person is required.
Traps
Questions often swap terms: grounding versus bonding, isolation versus de-energization, and arc-rated versus flame-resistant. Another common trap is treating voltage as the sole determinant of severity, or assuming that rubber gloves alone permit contact with any energized part.
Rule of thumb
Treat every conductor as energized until it has been tested, grounded, and tagged - and remember that testing proves absence of voltage only at the moment of the test.
Worked example
If clearing time doubles while fault current stays constant, incident energy roughly doubles; halving the time through faster protection roughly halves it. Distance matters more, since incident energy falls off sharply with distance.