A power cord includes multiple current-carrying wires covered by an outer insulating layer, each wire including a current-carrying conductor covered by an insulating layer. At least one wire further includes a shield layer covering the insulating layer and a metal conductor between the insulating layer and the shield layer. The shield layer is formed of a band wound around the metal conductor and insulating layer. The outward-facing surface of the band is insulating; the inward-facing surface has one or more conductive regions and one or more insulating regions. One insulating region is located along a longitudinal trailing edge of the band. Consecutive turns of the band partially overlap each other; the trailing edge of a subsequent turn is disposed over part of a previous turn. The structure ensures effective insulation of the metal conductor from other components. The power cord is used in a leakage current detection and interruption device.

A system and method that identify a location and/or magnitude of a ground fault in a circuit having a bus that connects battery strings with loads and a ground reference between the loads are provided. Potential of the bus is shifted relative to a ground reference in a first direction. A first impedance in the bus between the battery strings and the ground reference is determined, and the bus is shifted relative to the ground reference in a second direction. A second impedance in the bus between the battery strings and the ground reference is determined. A location and/or severity of a ground fault is determined based on a relationship between the first impedance and the second impedance.

A system and method that identify a location and/or magnitude of a ground fault in a circuit having a bus that connects battery strings with loads and a ground reference between the loads are provided. Potential of the bus is shifted relative to a ground reference in a first direction. A first impedance in the bus between the battery strings and the ground reference is determined, and the bus is shifted relative to the ground reference in a second direction. A second impedance in the bus between the battery strings and the ground reference is determined. A location and/or severity of a ground fault is determined based on a relationship between the first impedance and the second impedance.

An arrangement for detecting arcs in a low-voltage circuit has at least one voltage sensor for periodically determining voltage values of the low-voltage circuit and at least one current sensor for periodically determining current values of the low-voltage circuit. A first control unit is connected to the voltage sensor and the current sensor, has a processor, and is configured in such a way that the presence of a switch arc is determined on the basis of the determined voltage values and current values. A switch arc detection signal is output if a switch arc is determined to be present.

An electrical device includes a first terminal structured to electrically connect to a power source; a second terminal structured to electrically connect to a load; a voltage sensor electrically connected to a point between the first and second terminals and being structured to sense a voltage at the point between the first and second terminals; a switch electrically connected between the first terminal and the second terminal; and a control unit structured to detect a power quality event in the power flowing between the first and second terminals based on the sensed voltage and to control a state of the switch based on the detected power quality event.

Devices herein may include conductor lines connected between a power supply and load, each of the conductor lines coupled to an AC contactor and a contactor control circuit, wherein the contactor control circuit is operable to open and close one or more contactors of the AC contactor. The devices may further include a current transformer coupled to the conductor lines, the current transformer operable to output a secondary current corresponding to a primary current magnitude of an electrical current not flowing to the load, wherein the AC contactor is connected between the power supply and the load. Devices may further include a zero cross detection circuit operable to generate an interrupt at each of a plurality of zero crossings for a microprocessor, and determine whether to open the one or more contactors of the AC contactor in a predetermined optimum interval calculated with respect to the zero crossing points.

Devices herein may include conductor lines connected between a power supply and load, each of the conductor lines coupled to an AC contactor and a contactor control circuit, wherein the contactor control circuit is operable to open and close one or more contactors of the AC contactor. The devices may further include a current transformer coupled to the conductor lines, the current transformer operable to output a secondary current corresponding to a primary current magnitude of an electrical current not flowing to the load, wherein the AC contactor is connected between the power supply and the load. Devices may further include a zero cross detection circuit operable to generate an interrupt at each of a plurality of zero crossings for a microprocessor, and determine whether to open the one or more contactors of the AC contactor in a predetermined optimum interval calculated with respect to the zero crossing points.

A community dock safety system includes a plurality of voltage detectors is distributed about the community dock. Each voltage detector includes a voltage detector circuit that detects an electric voltage between a ground and at least one of the dock frame or the water. A master unit is responsive to each voltage detector status signal and controls a switch that disconnects the central power source from the electrical wire associated with each pedestal when the voltage detector status signal from at least one of the plurality of voltage detectors indicates that an electrical shock hazard has been detected. The master unit also includes a central wireless communication unit that communicates data received from the plurality of voltage detectors to a remote unit.

A power circuit with a first transistor, including a first terminal connected to a first node, a second terminal connected to an input node, and a control terminal connected to a first control node, and a second transistor, including a first terminal connected to the first node, a second terminal connected to an output node, and a control terminal connected to a second control node. A third transistor includes a first terminal connected to the first control node, a second terminal connected to a second node, and a control terminal, and a fourth transistor includes a first terminal connected to the output node, a second terminal connected to the second control node, and a control terminal connected to a third node. The power circuit also includes a current limiting circuit coupled between the second node and the third node.

A power circuit with a first transistor, including a first terminal connected to a first node, a second terminal connected to an input node, and a control terminal connected to a first control node, and a second transistor, including a first terminal connected to the first node, a second terminal connected to an output node, and a control terminal connected to a second control node. A third transistor includes a first terminal connected to the first control node, a second terminal connected to a second node, and a control terminal, and a fourth transistor includes a first terminal connected to the output node, a second terminal connected to the second control node, and a control terminal connected to a third node. The power circuit also includes a current limiting circuit coupled between the second node and the third node.