The integrity and surface condition of the tool should be checked before the test. There should be no cracks, flying arc marks, burning, perforation, melting and aging on the surface of the tested products. Those found to be unsatisfactory should be treated or stopped using. Electrical insulating tool test is mainly to do AC voltage withstand test, live tool also needs to do operation wave impact test. Insulation resistance should be measured before and after withstanding voltage.
Insulation tools made of rubber materials (such as rubber shoes, rubber boots, rubber gloves) should be connected with a milliampere meter at the ground end to read the current during the withstand voltage test. The luminescent voltage should also be measured for the tools of electroscope. In order to obtain more accurate values, the transformer with small variable ratio can be slowly boosted and repeated three times.
Pressurized electrodes should be selected according to the different shapes of the subjects. Insulating tools such as rubber shoes, rubber boots, rubber gloves and so on, generally use tap water as the electrode (the inner part of the sample is mixed with water and immersed in water, the high-voltage lead is led into the internal water, and the external water tank is grounded by a milliampere meter). The upper edge of the sample is 2-4 cm away from the inside and outside of the water surface, so it can not be wetted. Insulating rubber pads and blankets can be made of metal plates as electrodes. It should be guaranteed to withstand voltage on the parts used, and distance should be left at the edge of the test piece to avoid discharge along the surface. Insulating rods, insulating rods and insulating ropes can be tightly wrapped with bare metal wires as electrodes.
