Which test is commonly used to check insulation integrity in new wiring and involves applying high voltage?

• A. Continuity test
• B. Resistance to earth test
• C. Hipot test
• D. Ground fault test

Answer: (C)

Insulation integrity is about whether the insulation can withstand voltage without breaking down. To check this, a high-potential (hipot) test applies a voltage well above normal operating levels between conductors and between conductors and earth. This deliberately stresses the insulation so that any weak spots, cracks, moisture, or poor spacing will reveal themselves as leakage or breakdown. In new wiring, performing a hipot test helps confirm the dielectric strength of the insulation before the system is energized.

The other tests focus on different things: a continuity test simply confirms there is a complete electrical path, not how well insulation resists high voltage; a resistance-to-earth test looks at grounding pathways rather than insulation strength; and a ground-fault test checks leakage behavior and protective-device response, not the insulation’s voltage withstand capability.