An arc fault circuit interrupter includes line and load terminals, separable contacts, a current sensor sensing current flowing between the terminals and associated with one type of load, and a first arc fault detection circuit generating a first trip signal responsive to the sensed current. A second arc fault detection circuit collects a plurality of sensed current samples for a current line cycle and also for a previous line cycle, determines a total current value from a peak current of the current line cycle samples, employs the total current value and some of the samples to determine the type of load, and generates a second trip signal responsive to the sensed current and the determined type of load. A trip circuit generates a third trip signal responsive to the first and second trip signals. An operating mechanism opens the contacts responsive to the third signal.