Patent ID: 7746605

Claim:
An arc fault circuit interrupter for a power circuit including a plurality of alternating current half cycles, said arc fault circuit interrupter comprising: a line terminal; a load terminal; separable contacts electrically connected in series between said line terminal and said load terminal; a neutral conductor; an operating mechanism structured to open and close said separable contacts, said operating mechanism being structured to trip open said separable contacts in response to a trip signal; a current sensor structured to sense current flowing through said separable contacts; a voltage sensor structured to detect a plurality of voltage zero crossings between said load terminal and said neutral conductor, a consecutive pair of said voltage zero crossings defining a corresponding one of said half cycles; and a processor cooperating with said current sensor and said voltage sensor to detect a resistive series arc in series with said separable contacts, said processor comprising a routine structured to determine, for each of said half cycles, a plurality of samples of said sensed current, an offset value from an average of a plurality of said samples of said sensed current proximate the voltage zero crossings for the corresponding one of said half cycles, a plurality of adjusted samples of said sensed current, each of said adjusted samples being a corresponding one of said samples of said sensed current adjusted by said offset value, a profile corresponding to a resistive series arc as a function of a plurality of said samples of said sensed current and said adjusted samples, and said trip signal in response to a number of occurrences of said profile for a number of said half cycles.