What is spark test?
A spark test is an inline voltage test used either during cable manufacturing or during a rewinding process. Spark testing is primarily for low voltage insulations and medium voltage non-conducting jacket or sheaths. The test unit generates an electrical cloud around the cable which in high frequency AC units appears as a blue corona around the cable. Any pin holes or faults in the insulation will cause a grounding of the electrical field and this flow of current is used to register an insulation fault.