Fire Risk and Failure Mechanism of Copper Wire under Overcurrent Fault Condition

This paper describes the overcurrent tests that were conducted on a copper wire used in ordinary life in China (AC 220 V). These tests were conducted to evaluate the fire potential that may result from overcurrent faults. Results of these tests showed that the typical appearances of overcurrent fault could be divided into three steps, i.e. smoking, redness and breakdown etc. It also showed that the beginning time of smoking, redness and breakdown decreased as the power of the electrical applications increasing. After a person can find the overcurrent fault by seeing the smoke formed by the eroding of the insulation, a fire may begin in 4s to 7s.