Abstract: In order to determine the location of the arc fault point when the line overcurrent occurs, the overcurrent faults of AA8030 aluminum alloy wire under different overcurrent conditions are simulated, and the microstructure characteristics of the melt marks in different areas of overcurrent of the wire are analyzed by field emission scanning electron microscope. The results show that the micromorphological characteristics of the melting marks at the arc fusion point are honeycomb and snowflake. The signature micro morphology of the fusion mark in the non- arc area is the needle- shaped trace. The characteristic microscopic appearance of the slag area outside the arc melting point is spherical trace. This conclusion can provide reference for investigators to judge the fault point of overcurrent arc.

Key words: electrical fire, aluminum alloy conductors, overcurrent, melt trace, scanning electron microscopy