Abstract: An apparatus for smart frequency selection in a ground monitor apparatus is disclosed. The apparatus includes an energy measurement circuit that measures an energy level at a test frequency in an equipment grounding conductor between a load and a power source and an energy comparator that compares the measured energy level with an energy threshold. The apparatus includes a continuity signal circuit that injects a continuity signal with a frequency at the test frequency in the equipment grounding conductor at an energy level above the energy threshold in response to the energy comparator determining that the measured energy level is below the energy threshold. The continuity signal is an indicator for continuity of the equipment grounding conductor between the power source and load.

Abstract: An apparatus for phase operation indication includes a phase filter that filters a ground monitor signal from one or more phase conductors supplying power to a load and injects the ground monitor signal in an equipment grounding conductor run with the one or more phase conductors or receives the ground monitor signal from a signal generator and injects the ground monitor signal on the one or more phase conductors. The ground monitor signal includes a test frequency different than a line frequency of power supplied to the load. The apparatus includes at least one indicator circuit connected to at least one of the one or more phase conductors. An indicator circuit of a phase conductor provides a visual flashing signal in response to a voltage being present on the phase conductor, the at least one indicator circuit located at the phase filter.

Abstract: An apparatus for monitoring ground current includes a signal generation module that generates a plurality of AC components of different frequencies. An injection module injects the plurality of AC components on one or more phases of a set of power cables connecting a power source to a load. The set of power cables includes an equipment grounding conductor. The AC components are injected in the equipment grounding conductor. An AC detection module that determines an AC current corresponding to each frequency of the AC components present in current in the equipment grounding conductor, an AC threshold module determines if one or more of the AC currents is below an AC threshold, and a trip module opens a contact if the AC threshold module determines that at least one of the AC currents is below an AC threshold. The contact disconnects the power source from the power cables.

Abstract: An apparatus includes a resistor assembly with resistors connected in series between a first terminal and a second terminal of a pilot conductor and/or a ground return of a ground monitor. The pilot conductor injects an electrical signal in a ground of a power cable assembly. A zener diode assembly is connected between a zener connection point and the ground return. The zener connection point is the first or second terminal. The zener diode assembly includes zener diodes connected in series between the zener connection point and the ground return and is sized to clamp a voltage from the zener connection point to the ground return to a value less than a zener threshold voltage. The zener threshold voltage is set above a nominal voltage on the pilot conductor. The components of the apparatus are spaced to prevent an arcing fault current for voltages less than 3000 V.

Abstract: An apparatus includes an accessory module for a ground monitor that monitors current in a pilot conductor and/or a grounding conductor, which is in a power cable assembly connecting a power source and load. The pilot conductor injects a signal in the grounding conductor. The accessory module includes signal connectors that include multiple connection points. Each connection point provides access to a signal within the ground monitor. The connection points access signals for an output of a circuit monitoring current in the pilot conductor or ground return, a circuit responding to a peak current in the pilot conductor or ground return transitioning below a threshold, a circuit responding to an average current in the grounding conductor transitioning below a threshold, and/or a circuit indicating trip status of a contact in the power source. The connection point signals are in addition to signals from the ground monitor to the power source.