What is a recommended safety check to verify a circuit is de-energized before work?

• A. Plug a tester in to the outlet while touching terminals
• B. Use a properly rated tester or voltmeter to confirm zero voltage
• C. Measure resistance with a multimeter while energized
• D. Ask a colleague for confirmation

Answer: (B)

Before you start any electrical work, you must verify there is no energy present at the work area. The best safety check is to use a properly rated tester or voltmeter to confirm there is zero voltage between the conductors you’ll be working with. This direct measurement shows that the circuit is de-energized and safe to handle. Always test the tester on a known live source first to be sure it’s working, and follow any lockout/tagout procedures as required.

Other approaches don’t reliably verify safety. Plugging a tester in while you’re touching terminals can expose you to shock or arc flash and might not detect all live conditions. Measuring resistance on a circuit that is energized is not valid and can damage the meter or give misleading results. Relying on a colleague’s word isn’t a safe substitute for an actual voltage check.