Wire Fusing Time

A test sample wire is strung horizontally such that it hangs without resting on any surface. A current 2.5 times that of the "free air rated current" is applied to the sample via a DC power source. The sample is held at this constant current until a current interruption (open circuit) occurs with a maximum allowable time of five minutes. The time to open circuit, if under five minutes, is the reported test result.