An evaluation method of electrical fire hazard caused by tracking breakdown

Degraded insulators of electronic components tend to ignite even when electrical energy supplied to them is less than 50 watts. This is also the case when the insulators are made of self extingushing polymeric materials. To evaluate the degradation of insulators, causes for the variation of data are investigated primarily on the tracking breakdown accelerated by heating, wetting and accullll1ation of contaminants?testing conditions described in IEC pub. 112.