The purpose of this test is to measure the resistance of the outer surface of the insulation in a high humidity environment. This is to ensure that the resistance along the outer surface is large enough to prevent leakage current between connections.
The following parameters can be adjusted for the test:
Perform visual examination of the specimen. Record any observed defects.
Wrap two conductive electrodes around the specimen spaced 1 inch ± .005 inch apart between the electrode's nearest edges.
Connect the electrodes to the test circuit and place the specimen into a sealed chamber at room temperature with relative humidity between 90 – 96%.
After a specified conditioning duration, a voltage is applied across the electrodes and the leakage current is measured.
Report the specimen separation distance, measured leakage current, and humidity.