Microscopic characteristics of copper wires with short-circuit molten marks in electrical fire

Abstract Electrical fire accidents occurred frequently all over the world in recent years, which had caused a large number of casualties and property losses. The main cause of electrical fire is electrical wire short circuit fault. Investigations of the characteristic and influence factors of the molten marks play an important role to determine the cause of fire. In the present work, microscopic characteristics of copper wires with short-circuit molten marks in electrical fire were investigated. Primary and secondary short-circuit molten marks (PMMs and SMMs) of copper wires were prepared by simulation test. The micro-morphology, microstructure and chemical composition of molten marks were observed and compared. Based on the quantitative characterization, effects of different overload currents and heating temperatures on the microstructure of molten marks were analyzed. The results would provide fundamental information for cause identification of the electrical fire.