In one example, a ground fault circuit interrupter is provided. It may include a current imbalance detection circuit configured to provide a leakage signal and a main processing circuit including a processor. The leakage signal may correspond to a current imbalance between a supply path and a return path. The processor may be configured to receive the leakage signal, analyze a time pattern of the leakage signal, determine whether a ground fault exists based on analysis of the time pattern, and generate a first trigger signal if the ground fault is determined to exist. The ground fault circuit interrupter may further include a back-EMF detection circuit configured to provide a back-EMF detection signal. Methods for detecting and responding to a ground fault are also provided.

In one example, a ground fault circuit interrupter is provided. It may include a current imbalance detection circuit configured to provide a leakage signal and a main processing circuit including a processor. The leakage signal may correspond to a current imbalance between a supply path and a return path. The processor may be configured to receive the leakage signal, analyze a time pattern of the leakage signal, determine whether a ground fault exists based on analysis of the time pattern, and generate a first trigger signal if the ground fault is determined to exist. The ground fault circuit interrupter may further include a back-EMF detection circuit configured to provide a back-EMF detection signal. Methods for detecting and responding to a ground fault are also provided.

A fault protection arrangement may include a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end. The fault protection arrangement may include a neutral grounding resistance monitor assembly, coupled to the neutral grounding resistor, where the neutral grounding resistance monitor assembly includes a sense circuit, coupled to the ground end of the neutral grounding resistor; and an injection signal generator, arranged to generate a frequency of 240 Hz or greater.

A protective wiring device disposed in an electrical distribution system, the device comprising: a plurality of line terminals comprising a line-side phase terminal and a line-side neutral terminal; a plurality of load terminals comprising a load-side phase terminal and a load-side neutral terminal; a line conductor electrically coupling the line-side phase terminal to the load-side phase terminal; a neutral conductor electrically coupling the line-side neutral terminal to the load-side neutral terminal; a controller configured to transmit wirelessly data derived from signals present on at least one of the line conductor or the neutral conductor and to receive wirelessly receive at least one command.

A circuit interrupter including a first electrical conductor, a second electrical conductor, separable contacts, an operating mechanism configured to open and close said separable contacts, a trip circuit configured to trip open said separable contacts, a ground fault detection circuit configured to sense a difference between a current through the first electrical conductor and a current through the second electrical conductor and to output an output signal based on said sensed difference, a power supply, a confirmation circuit structured to input a confirmation signal to the power supply, and a processor configured to receive said direct current power and said output signal. The processor is configured to determine whether a characteristic of said confirmation signal is present in said output signal and to control the trip circuit based on said determination.

A ground fault circuit interrupter (GFCI) can include a current transformer (CT) comprising a single core, a first winding wound around the single core, and a second winding wound around the single core. The GFCI can include a ground fault (GF) detection module operatively connected to the first winding to receive signals from the first winding and configured to determine whether a line-to-ground fault exists. The GFCI can also include a GN stimulus operatively connected to the second winding to provide a GN stimulus signal to the second winding. The GFCI can also include a grounded neutral (GN) detection module operatively connected to second winding and configured to receive signals from the second winding to determine whether a neutral-to-ground fault exists.

A ground fault circuit interrupter (GFCI) can include a current transformer (CT) comprising a single core, a first winding wound around the single core, and a second winding wound around the single core. The GFCI can include a ground fault (GF) detection module operatively connected to the first winding to receive signals from the first winding and configured to determine whether a line-to-ground fault exists. The GFCI can also include a GN stimulus operatively connected to the second winding to provide a GN stimulus signal to the second winding. The GFCI can also include a grounded neutral (GN) detection module operatively connected to second winding and configured to receive signals from the second winding to determine whether a neutral-to-ground fault exists.

A ground fault current interrupter circuit includes a plurality of comparators, threshold generation circuitry, and a plurality of timer circuits. Each of the comparators is configured to compare a threshold voltage to a signal representative of a difference of current flow to a load and current flow from the load. The threshold generation circuitry is configured to generate a plurality of different threshold voltages. Each of the different threshold voltages is provided as the threshold voltage for one of the comparators. Each of the comparators is coupled to one of the timer circuits, and the one of the timer circuits is configured to activate a fault signal responsive to activation of an output of the comparator for a time that is related to the threshold voltage provided to the comparator. The time increases with lower values of the threshold voltage.

A transformer assembly comprises at least one transformer having a core. A primary winding is positioned on a first portion, a secondary winding is positioned on a second portion of the core. A neutral winding may be positioned on a third portion of the core. The secondary winding may receive an induced flux produced by an earth surface potential (ESP) via a system ground and/or receive an induced zero sequence flux produced by a non-linear load. The neutral winding may be configured to provide a mitigating flux to the secondary winding. The transformer may also be used as a filter for either GIC or triplen harmonic mitigation. In this case, the primary windings receive the zero sequence current (GIC or triplen harmonics) and the flux may be cancelled in neutral winding such that the zero sequence currents circulate between the zero sequence source and the filter transformer.

The line power and neutral conductors for an arc fault sensing circuit interrupter such as in a miniature circuit breaker are arranged as a rigid conductor surrounding and holding an insulated flexible conductor when passing through the Ground Fault Interrupter current transformer. Voltage metering takes place across the rigid conductor to enable arc fault detection and ground fault detection in the miniature circuit breaker within the space of a single current transformer.