USCG Exam PracticeHand/power tools, measuring instruments, and maintenance
When using a multimeter to measure resistance in a shipboard circuit, the circuit must be in what condition before the measurement is taken?
- A. Energized and under normal load
- ✓ De-energized and isolatedCorrect
- C. Energized but with the load disconnected
- D. De-energized but with the load still connected
Why B is correct
An ohmmeter uses its own internal battery as a source; external voltage on the circuit will produce false readings or damage the meter. The circuit must be de-energized and isolated before resistance measurement is attempted.
Cited:NEETS Mod. 3 §1-3