What does the dry withstand voltage test verify?

• A. That the insulator can withstand a specified voltage under dry, clean conditions without breakdown.
• B. That the insulator can withstand a specified voltage under wet conditions.
• C. That the insulator has no surface leakage current at all.
• D. That the insulator can withstand mechanical loading.

Answer: (C)

The dry withstand voltage test checks the insulation’s dielectric strength under dry, clean conditions. A specified voltage is applied across the insulator for a set period, and the goal is that the insulation does not break down or flash over during that time. Surface leakage current isn’t the defining criterion—some leakage can occur in practice, but what matters is that the material withstands the voltage without breakdown when dry. This test differs from the wet withstand test, which assesses performance under moisture. Mechanical loading is unrelated to this electrical strength test.