What is necessary for voltage drop testing to yield accurate results?

For voltage drop testing to yield accurate results, it is essential that the circuit is energized. This is because voltage drop testing involves measuring the voltage difference across a component or section of a wiring circuit while it is under normal operating conditions. When the circuit is energized, current flows through the circuit, and the voltmeter can detect any drop in voltage that occurs due to resistance in the wiring, connectors, or components.

If the circuit were to be disconnected, there would be no current flow, resulting in no voltage drop to measure. Without an energized circuit, testing could lead to misleading results or an inability to identify issues such as high resistance connections or faulty components. Therefore, an energized circuit is crucial for accurately diagnosing electrical problems through voltage drop testing.