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 electric power sensor includes a sensor pad and an electric terminal. The sensor pad includes a flexible substrate that defines a first surface and a second surface that opposes the first surface. Additionally, the sensor pad includes an electrically-conductive layer applied to the first surface of the flexible substrate. The sensor pad further includes an adhesive layer applied to the second surface of the flexible substrate. The electric terminal is coupled to the electrically-conductive layer of the sensor pad.

Abstract: An apparatus includes an energy storage module that receives power from an AC power source. The energy storage module is sized to store electrical energy received from the AC power source that is sufficient to open one or more contacts when the AC power source is not present. The contacts disconnect electrical power to a load and the electrical energy is stored in a DC energy storage device. A connection module connects the energy storage device in series with a trip contact, a trip circuit, and an auxiliary contact. The trip contact closes in response to a trip signal. The trip circuit disconnects the one or more contacts in response to being energized, and the auxiliary contact opens in response to opening of the one or more contacts and disconnects power to the trip circuit. A disconnect module periodically disconnects electrical power from the trip circuit and the auxiliary contact.

Abstract: A watchdog apparatus for monitoring ground current is disclosed. A system and method also perform the functions of the apparatus. The watchdog apparatus includes a watchdog signal module that generates a watchdog signal. The watchdog signal is generated at a specific interval and includes an identifiable characteristic. The watchdog signal module is part of a device being monitored for functionality. The apparatus, in some embodiments, includes a signal monitoring module that determines if the watchdog signal includes the identifiable characteristic, and an alert module that sends and alert signal in response to the signal monitoring module determining that the watchdog signal does not include the identifiable characteristic.

Abstract: An apparatus includes a signal generation module that injects a signal in a pilot conductor with one or more AC components. The pilot conductor is connected to a grounding conductor of power cables connecting a power source to a load. A frequency change module periodically changes a frequency of each of the AC components, a current monitor module monitors current in the pilot conductor or ground return, an AC detection module determines an AC current for each AC component, and an AC threshold module determines if one or more of the AC currents determined by the AC detection module is below an AC threshold. A trip module opens a contact in response to determining that at least one of the AC currents is below an AC threshold for longer than an AC current time threshold. The contact disconnects the power source from the set of power cables.

Abstract: An apparatus includes a signal generation module that injects a signal in a pilot conductor with one or more AC components. Pilot conductor current is injected in a grounding conductor of power cables connecting a source to a load. A current monitor module monitors affected current in the pilot conductor. A DC detection module determines a DC current present in the current. A DC minimum threshold module determines if the DC current is below a DC current threshold. An AC detection module determines an AC current of each frequency of the AC components. An AC threshold module determines if any of the AC currents is below an AC threshold. A trip module opens a contact after determining that the DC current is below the DC current minimum threshold and/or determining that at least one of the AC currents is below an AC threshold. The contact disconnects the source.

Abstract: An apparatus includes a signal generation module that injects a signal in a pilot conductor. The signal includes two or more AC components. Current in the pilot conductor is injected in a grounding conductor of power cables connecting a power source to a load, and the grounding conductor is connected to a ground return. A current monitor module monitors current in the pilot conductor or ground return, an AC detection module determines an AC current corresponding to each of the two or more AC components present in the monitored current, and an AC threshold module determines if one or more of the AC currents is below an AC threshold. A trip module opens a contact in response to determining that at least one of the AC currents is below an AC threshold for longer than an AC current time threshold. The contact disconnects the power source from the power cables.

Abstract: A signal generation module injects a signal in a pilot conductor with a DC component and one or more AC components. Pilot conductor current is injected in a grounding conductor of power cables connecting power source to load. A current monitor module monitors current in the pilot conductor or ground return, a DC detection module determines DC current present in the monitored current, an AC detection module determines AC current corresponding to each frequency of the AC components in the monitored current, a DC minimum threshold module determines if the DC current is below a DC current minimum threshold, an AC threshold module determines if any of the AC currents is below an AC threshold, and a trip module opens a contact after determining that the DC current is below the DC current minimum threshold or that at least one of the AC currents is below an AC threshold.

Abstract: According to some embodiments, an assembly includes at least one of a plug or a receptacle. The plug includes a first electrical insulator that isolates a plurality of first electrical contacts. The first electrical insulator includes two separable halves. The receptacle includes a second electrical insulator that isolates a plurality of second electrical contacts. The second electrical insulator may also include two separable halves. The plurality of first electrical contacts are engageable with the plurality of second electrical contacts to electrically couple the plug and receptacle.

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.