hipot

Hipot, short for high-potential test, is a dielectric withstand test used to verify the insulation of electrical equipment by applying a higher-than-operating voltage between conductive parts and ground, or between insulated parts, to induce a leakage current. The test assesses whether the insulation can withstand voltage stresses without penetrating or breaking down.

There are two main variants: AC hipot and DC hipot. AC hipot applies an alternating voltage at a specified level and duration; DC hipot applies a direct voltage, often higher than the operating voltage, with a ramp-up, a hold period, and a controlled discharge. Leakage current is monitored and compared against acceptance limits. The test is designed to reveal insulation defects such as pinholes, cracks, moisture ingress, or inadequate creepage and dielectric distances.

Setup and procedure: A hipot tester (insulation tester) is connected between the points under test and ground or between different conductors. The tester increases voltage according to the selected profile and measures leakage current. If the current exceeds the specified limit or a breakdown occurs, the test is aborted and the unit fails. After testing, the device is discharged safely before handling.

Applications and safety: Hipot testing is used for electrical equipment, power supplies, cables, insulation components, consumer electronics, and medical devices to assess dielectric strength. Limitations include that hipot tests simulate short-term voltage stress and do not guarantee long-term insulation performance under all operating conditions. Because high voltages are involved, hipot testing requires trained personnel, proper safety procedures, interlocks, and appropriate protective equipment.