What is High Potential Ability Test (HIPOT)?

The lmportance of HiPOT Testing

The hipot test is a nondestructive test that determines the adequacy of electrical insulationfor the normally occurring over voltage transient. This is a high-voltage test that is appliedto all devices for a specific time in order to ensure that the insulation is not marginal.

Hipot tests are helpful in finding nicked or crushed insulation, stray wire strands orbraided shielding, conductive or corrosive contaminants around the conductors, terminalspacing problems, and tolerance errors in cables. inadequate creepage and clearancedistances introduced during the manufacturing process.

When voltage is applied across an insulation system, part of the current leaks into, throughand around the insulation. During high-voltage direct current testing, capacitive chargingcurrent, insulation absorption current, insulation leakage current, and bypass current areall present to varying extents.

The production-line hipot test, however, is a test of the manufacturing process to determinewhether the construction of a production unit is about the same as the construction of theunit that was subjected to type testing. Some of the process failures that can be detected bya production-line hipot test include, for example, a transformer wound in such a way thatcreepage and clearance have been reduced. Such a failure could result from a new operatorin the winding department.