Abstract: A circuit interrupter is structured to protect a protected circuit. The circuit interrupter includes a ground fault current sensor structured to sense a ground fault current in the protected circuit and a processor including a routine structured to perform a ground fault output self-test. The ground fault output self-test includes to output a trip signal within a predetermined phase angle of a zero-crossing of current flowing through the protected circuit, to stop outputting the trip signal before the zero-crossing, to determine whether the trip signal caused a pulse in the ground fault current, and to determine whether the circuit interrupter passed the ground fault output self-test based on whether the trip signal caused a pulse in the ground fault current.

Abstract: A circuit interrupter including a line conductor, a neutral conductor, a power supply, a ground fault current transformer structured to sense a ground fault current from current flowing through the line and neutral conductors, a grounded neutral detection circuit including a filtering stage structured to high-pass filter the ground fault current, and a processor structured to receive an output of the grounded neutral detection circuit and to determine whether a grounded neutral is present based on the output of the grounded neutral detection circuit.

Abstract: A circuit interrupter is structured to protect a protected circuit. The circuit interrupter includes a ground fault current sensor structured to sense a ground fault current in the protected circuit and a processor including a routine structured to perform a ground fault output self-test. The ground fault output self-test includes to output a trip signal within a predetermined phase angle of a zero-crossing of current flowing through the protected circuit, to stop outputting the trip signal before the zero-crossing, to determine whether the trip signal caused a pulse in the ground fault current, and to determine whether the circuit interrupter passed the ground fault output self-test based on whether the trip signal caused a pulse in the ground fault current.

Abstract: A circuit interrupter including a line conductor, a neutral conductor, a power supply, a ground fault current transformer structured to sense a ground fault current from current flowing through the line and neutral conductors, a grounded neutral detection circuit including a filtering stage structured to high-pass filter the ground fault current, and a processor structured to receive an output of the grounded neutral detection circuit and to determine whether a grounded neutral is present based on the output of the grounded neutral detection circuit.

Abstract: Self-test circuitry for testing a circuit interrupter includes an active element coupled to an operating mechanism, a first sub-circuit for temporarily disabling the active element, a second sub-circuit structured to generate a simulated ground fault condition, and a processing unit coupled to the ground fault detection circuitry. The first sub-circuit and the second sub-circuit, the processing unit being structured and configured to control the first sub-circuit to temporarily disable the active element and to control the second sub-circuit to generate the simulated ground fault condition when the active element is disabled. Also, self-test circuitry that includes a sub-circuit structured to generate a simulated ground fault condition and a processing unit structured and configured to control the sub-circuit to generate the simulated ground fault condition only during a predetermined portion of a half cycle of energy passing through the circuit interrupter.

Abstract: Self-test circuitry for testing a circuit interrupter includes an active element coupled to an operating mechanism, a first sub-circuit for temporarily disabling the active element, a second sub-circuit structured to generate a simulated ground fault condition, and a processing unit coupled to the ground fault detection circuitry. The first sub-circuit and the second sub-circuit, the processing unit being structured and configured to control the first sub-circuit to temporarily disable the active element and to control the second sub-circuit to generate the simulated ground fault condition when the active element is disabled. Also, self-test circuitry that includes a sub-circuit structured to generate a simulated ground fault condition and a processing unit structured and configured to control the sub-circuit to generate the simulated ground fault condition only during a predetermined portion of a half cycle of energy passing through the circuit interrupter.