Patent ID: 8421473

Claim:
An apparatus for a power circuit providing an alternating current to a load, said apparatus comprising: a high frequency current sensor structured to cooperate with said power circuit to provide a high frequency current signal; a voltage zero crossing detector structured to cooperate with said power circuit to provide a voltage zero crossing signal; a high pass filter structured to provide a filtered current signal from the high frequency current signal; a threshold comparator structured to provide an output when the filtered current signal exceeds a predetermined value; and a processor structured to receive the voltage zero crossing signal and the output of the threshold comparator and output a trip signal in response to undesired series arcing by detecting an unsymmetrical high frequency signal for a predetermined number of cycles, wherein each of the predetermined number of cycles includes a positive half cycle and a negative half cycle, and wherein said unsymmetrical high frequency signal includes a first high frequency signal for the positive half cycle and a second high frequency signal for the negative half cycle, with an asymmetry between the first and second high frequency signals.