What is hi pot testing?

'Hi-pot' is short for 'high potential'. So, a 'hi-pot' test is a 'high-potential' test, and is used to test the insulation resistance of electricity-supply equipment, such as underground cables, etc. It does this by subjecting the insulation to a continuous (d.c.) over-voltage for a given period of time. The magnitude of the test voltage, and the duration of the test, is laid down by the standards that apply to the electrical components being tested.