Study on the type of voltage-to-sheath line short-circuit faults and the characteristics of melt traces

This study examines the impact of voltage levels on the short circuit types and melts trace characteristics of sheathed wires using a standardized heating cone. The experimental results indicate that low voltage conditions (≤ 140 V) primarily result in metal short-circuit faults with regular or irregular I-shaped melt traces. Medium voltage conditions (140 V-280 V) lead to carbonized path-type short circuits, characterized by complex arc melt traces. High voltage conditions (≥ 280 V) predominantly cause metal melting-type short circuits with distinct fusing features. As voltage increases, the arc energy and thermal effects intensify, resulting in coarser grains and fewer but larger pores in the melt trace area. These findings provide valuable theoretical insights for electrical fire prevention and fault assessment in sheathed wires and offer practical guidelines for improving safety measures in electrical installations.