Industrial arc fault circuit interrupter and method of detecting arcing conditions

A method of detecting arcing conditions includes sensing current and HF signals therefrom; bandpass filtering the HF signals and providing filtered signals; detecting peak signals and envelopes from the filtered signals; counting occurrences of the envelopes exceeding a first value; maintaining temporary values corresponding to the peak signals; determining a trip time as a function of the current; determining if any peak signal is greater than a second value, and responsively increasing a temporary value and, otherwise, decreasing the temporary value; determining if a predetermined function of the temporary values is greater than a fifth value, and adding the temporary values to an accumulator, and otherwise, decreasing the accumulator; and tripping open the power circuit if: a difference between the occurrences of current and immediately previous half cycle having the same polarity is at least two, the accumulator is greater than a seventh value, and the trip time is reached.