Patent ID: 8218274

Claim:
A direct current arc fault circuit interrupter comprising: separable contacts; an operating mechanism structured to open and close said separable contacts; a trip circuit cooperating with said operating mechanism to trip open said separable contacts, said trip circuit comprising: a number of alternating current sensors structured to sense a current flowing through said separable contacts, a direct current sensor structured to sense the current flowing through said separable contacts, a number of filter circuits cooperating with said number of alternating current sensors to output a number of alternating current signals, a number of peak detectors cooperating with said number of filter circuits to output a number of peak current signals, and a processor cooperating with at least said number of peak detectors and said operating mechanism, said processor being structured to input the number of peak current signals as a plurality of peak current signals or input the number of peak current signals and determine the plurality of peak current signals, said processor also being structured to determine if the plurality of peak current signals exceed corresponding predetermined thresholds for a predetermined time, and responsively cause said operating mechanism to trip open said separable contacts, wherein said processor further cooperates with said direct current sensor to cause said operating mechanism to trip open said separable contacts, and wherein said processor is further structured to detect a level shift in the sensed current employing said direct current sensor.