A resettable switching apparatus, useful in a GFCI receptacle, has an auto-monitoring circuit for automatically testing various functions and structures of the device. The auto-monitoring circuit initiates an auto-monitoring routine which, among other things, establishes a test fault situation on either the positive or negative half-wave of the power cycle and determines whether the detection mechanisms within the device appropriately detect the test fault and whether the device would trip in the event of an actual fault. Additional functionality of the auto-monitoring circuit permits automatic verification that the device is properly wired, that is, not miswired, and determines whether the device has reached the end of its useful life.