Thermographic study of stainless steel cross-arm on overhead distribution system

Many new innovations in the pole top equipment were brought onto the market in recent years. A good example of that is the stainless steel cross-arm that is designed to replace the conventional wooden cross-arm for pole-top fire mitigation. The main objective of this study is to compare the thermal characteristics on both the stainless steel cross-arm and the wooden cross-arm at different leakage current levels. Our results show that the stainless steel arm has similar heat dissipation property at low current level of 10 mA compare with wooden cross-arm. However, at a current level of 90 mA, the build-up of heat causes the king bolt junction to heat up dramatically and smouldering of the wooden pole was observed. The time-lapse thermographic images of the heating process are presented. This paper also presents a low-cost solution of which the leakage current at the king bolt junction can be reduced.