Environmental factors affecting DC resistance to tracking of polyethylene

This paper discusses the environmental factors affecting DC resistance to tracking of polyethylene. The voltage, as determined under the conditions specified in the following, which will cause failure with the application of 50 drops of electrolyte, is used as a measure of the susceptibility of the material to tracking, it is called the CTI (contaminant tracking index). A tracking test was set up to investigate dc and ac tracking resistance of epoxy resin, phenolic resin and polycarbonate by IEC 112. The test solution was with 0.1 % ammonium chloride NH₄Cl in deionized water, giving a resistivity of approximately 4Ωm at 23°C. A droplet was applied at intervals to keep up the discharge between the two electrodes. Epoxy and phenolic resins are tracking type materials.