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.