Short-time withstand current of electrical apparatus

Most electrical apparatus should be able to withstand the short time high current. Generally it is believed that the temperature rise of apparatus is proportional to the I/sup 2/t (I denotes current and t time), therefore in the Lab we can increase the time and decrease the current to do an equivalent experiment based on the equal I/sup 2/t. But in this paper, the author find the equivalent experiment principle should be rather than I/sup 2/t. Detailed solution of the heat conduct equations is given, and the calculated results for Cu and Ag are listed.