High Voltage Testing of electrical equipment covers a wide range of techniques depending on the nature of the equipment and the type of test required. High Voltage testing is usually performed to qualify the device to operate safely during rated electrical conditions, a way to check the effectiveness of its insulation.

The objective sought during the high voltage testing will determine the type and amount of voltage applied and the acceptable current flow. If the high voltage testing target is getting the value of the insulation, we are speaking about Insulation Resistance Tests.

When we are looking for the breakdown voltage, the point where the dielectric fails allowing much current to flow, it is a Dielectric Breakdown Test, and this high voltage testing is usually a destructive test. When the test checks that the leakage current is below a preset safety limit for an established voltage value (below the breakdown voltage), we are speaking about a Dielectric Withstand Test, which is a non destructive high voltage testing, and through which we are also verifying the insulation integrity of the equipment.

All this high voltage testing is sometimes referred to as hipot (high potential) testing, but related testers differs much according to the test objective and whether they are on factory or on site. source