Reducing variability in inclined-plane tracking test results

Factors which cause variability in the results of inclined-plane tracking tests have been investigated. The effects of introducing shunt or stray capacitance across the test specimen, or of varying the contaminant flow rate, are measured. The discharge energy to the time of observation of initial damage shows less variability than the time-to-track criterion, and may be a more appropriate criterion for comparing the track resistance of materials.