What is insulation testing in cable harness testing??

Insulation testing is the test of resistance between dissimilar conductors by applying a high voltage. The following video explains the insulation testing of harnesses. Example: Apply 500 VDC and measure if the resistance between dissimilar conductors is greater than 100 MΩ.

Insulation testing is affected by humidity

In insulation testing, a high voltage such as 100 V DC to 1000 V DC is applied and the leakage current at that time is measured. Leakage current flows inside the insulator, but it also flows between conductors through the surface of the insulator. When the insulator surface is dry and clean, the leakage current is low; when the surface is humid and dirty, the leakage current tends to be high. This affects not only the test targets but also the jig wiring that connects the testers. Therefore, it is desirable to keep the testing room dry and clean.

What to do when an insulation test or self-diagnostic failure occurs during the rainy season

If humidity is thought to be the cause, perform self-diagnosis on the tester itself. In case of NG self-diagnosis, leave the tester and testing jig in a dry environment (less than 50% humidity) for several hours. (*An environment with 69% humidity may cause sparking or other abnormalities.) If humidity is removed, the self-diagnosis is OK. *Please conduct self-diagnosis by stand-alone.