汽车电气线路存在一定的火灾危险性,由过负荷、短路、接触不良等原因引起的火灾事故时有发生。其中电源线路过负荷是由于线路中流过的电流超出导线安全电流,致使导线过热,当达 There is a certain fire danger in the electric circuit of the automobile, and fire accidents caused by overload, short circuit, poor contact and so on occur from time to time. One power line overload is due to the current flowing in the line exceeds the wire safety current, resulting in wire overheating, when the up