Abstract: In order to study the fire risk of short-circuit fault caused by overcurrent of electric RVVB wire, this paper built a test platform for RVVB wire overcurrent induced short-circuit faults, and studied the fire process and trace of short circuit fault. The initial short circuit occurrence time, combustion characteristics and trace characteristics when the RVVB wire was short-circuited were studied. The results showed that when I≥ 45 A, the RVVB wire will appear short circuit breakdown phenomenon and cause open fire combustion; When I= 66 A, the average time of short-circuit fault induced by over-current is shortened from 1 803.4 s of I=45 A to 52.8 s, and the combustion time of open fire fluctuates from 16.4 s to 28.96 s, which increases the fire risk; The short-circuit fault induced by overcurrent in the RVVB wire will produce arc fusion marks such as sphere shape, semicircle shape, pointed shape, joint shape, pit shape, fracture shape,and overlapping shape, as well as splashing fusion marks with different diameters.The research results can provide a theoretical basis for the ignition mechanism of short circuit fault induced by over-current and the identification of weld marks.

Key words: RVVB wire; overcurrent; short circuit fault; a fire process