Non-tracking organic insulations and their application to electrical apparatus

The susceptibility to carbon tracking upon exposure to electrical arcs has always been a fundamental weakness of organic insulations. Although recent emphasis has teen on the development of organic materials with more versatile physical characteristics and improved high-temperature properties, comparatively little work has been published on compounding materials to specifically resist tracking under severe electrical arcing conditions. When electrical apparatus is exposed to moisture, salt fog or dust, leakage currents result which produce electrical arcing on the exposed surface of the insulation. Under severe conditions most organic materials will develop carbonized surface tracks and even porcelain insulators will crack and chip from thermal shock.