Internal Oxidation Mechanism for Nontracking Organic Insulations

An internal oxidation mechanism designed to eliminate the formation of conducting carbon paths in organic insulation exposed to electric arcs has been described. Mass spectrometer data on analysis of gases formed during electrical arcing provide evidence for this explanation. Data have been presented for several additives showing the degree of effectiveness in preventing creep tracking. For optimum effectiveness, it has been found that the additive should contain sufficient water of hydration as well as catalyst to prevent the formation of free carbon. Hydrated alumina in specific quantities has been found effective under all test conditions.