Patent ID: 7349188

Claim:
An arc fault detector for an electrical system, the arc fault detector comprising: a sensed current signal generator generating from current flowing in the electrical system a sensed current signal; an integrator repetitively integrating an absolute value of the sensed current signal over equal time intervals to generate integrated sensed current values; a change indicator generating for each most recently completed time interval, a change indication when the integrated sensed current value for the most recently completed time interval changes by at least a threshold amount from the integrated sensed current value for the preceding time interval; a summer repetitively summing for each most recently completed time interval the number of change indications generated over a selected number of the most recently completed time intervals to generate a change count; a memory storing the change counts for the selected most recently completed intervals in a sequence of change counts; and a processor comprising: detector means generating an arc signal in response to patterns in the sequence of change counts indicative of an arc; and reset means clearing the memory of the sequence of change counts in response to predetermined other patterns in the sequence of change counts indicative of events other than an arc.