General exam question G0B12
Subelement G0, ELECTRICAL AND RF SAFETY· Group G0B
What is the purpose of a power supply interlock?
- A.To prevent unauthorized changes to the circuit that would void the manufacturer’s warranty
- B.To shut down the unit if it becomes too hot
- C.To ensure that dangerous voltages are removed if the cabinet is opened (correct answer)
- D.To shut off the power supply if too much voltage is produced
WhyThe purpose of a power supply interlock is to ensure that dangerous voltages are removed if the cabinet is opened. A power supply interlock is a safety switch wired so that opening the equipment's cabinet automatically cuts off dangerous internal voltages, protecting anyone reaching inside from accidental shock, answer C. It isn't there to protect a warranty, doesn't function as thermal shutdown protection, and doesn't monitor for overvoltage output, those are different protective functions from what an interlock does, so A, B, and D are wrong.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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