How do you check for a ground wire?

To determine the presence and integrity of a ground wire, it's essential to measure the resistance between the ground wire and a known ground source while the power is turned off. This method involves using a meter or continuity tester to check for continuity, effectively ensuring that the ground wire is properly connected and functioning.

Turning off the power is crucial because it prevents electrical shock and allows for a safe measurement. Reading the wire to ground with a dedicated meter or continuity tester can confirm that the ground wire provides a low-resistance path, which is vital for safety in electrical systems. A good ground wire will show low resistance, indicating it is properly connected to the grounding system.

Other methods, such as reading the voltage with a multimeter or performing a visual inspection, do not specifically confirm the functionality of the ground wire in the same precise manner. Checking for insulation damage does not ascertain whether there is a proper connection to ground, which is critical for safety and compliance with electrical codes. Thus, option C represents the safest and most effective method for checking a ground wire.