Root Cause Analysis of Electric Fires and Risk Diagnosis of Parked Vehicles

Abstract

Generally, a vehicle's electrical circuits are protected against overcurrent. However, an overcurrent protector cannot completely prevent fires. In particular, fires that occur in parked vehicles are often caused by Joule heat and arc faults owing to contact failures, partial disconnection, arc tracking, and connection errors in the circuit that continues to receive electricity from the battery. Since the flowing current in such a case is not an overcurrent, the fuse will not react and may thereby cause a fire. Additionally, if a wire burns and causes a short circuit after the fire, the fuse will react to cut off the electricity supply, but cutting off the electricity supply after ignition has no significance. Furthermore, since an overcurrent protection device cannot determine whether Joule heat and arc faults are occurring in anelectrical circuit, a thermal imaging test is required in addition to visual inspection and should be conducted duringvehicle inspection.