Abstract: A zone selective interlocking system for electronic trip circuit breakers includes a plurality of downstream terminals, each downstream terminal connecting with at least one of a plurality of downstream electronic trip circuit breakers having input terminals. A restraint input circuit module, including a voltage comparator, is connected to the input terminals of each of the downstream electronic trip circuit breakers and the input terminals are shorted together providing a self-restraint signal for each downstream electronic trip circuit breaker at the occurrence of a downstream fault condition. The system also includes a plurality of upstream terminals, each upstream terminal connecting with at least one of a plurality of upstream electronic trip circuit breakers having input terminals.

Abstract: A system for testing an arcing fault detection system in an electrical distribution network having a line conductor carrying an electrical signal between a power source and a load, the arcing fault detection system including a sensor coupled to the line conductor for monitoring the electrical signal and generating a sensor signal representing the electrical signal, the arcing fault detection system generating an arc-indicative signal in response to the sensor signal having characteristics indicative of an arcing fault. The testing system couples the sensor to a test line simultaneously with the line conductor and periodically produces a test signal on the test line. The sensor simultaneously monitors the test signal and the electrical signal and produces a sensor signal representing both the test signal and the electrical signal when the test signal is present on the test line.

Abstract: A circuit breaker and method for interrupting the flow of electric current in a line having a load and a source including a first switch connected in series with the line and a first actuating device coupled to the first switch and adapted to be actuated by at least one activating signal, to move the first switch from the closed position to the open position. A resistor having a positive temperature coefficient of resistivity is connected in series with the first switch and a voltage limiting device is connected in parallel with the resistor. A second actuating device is coupled to the first switch and is adapted to be actuated by at least one remote control activating signal, to move the first switch to the open position or to the closed position. The second actuating device further includes a coil and a second switch connected to the coil and to the line, the second switch adapted for activating the coil upon the receipt of the remote control activating signal.

Abstract: A system for detecting arcing faults in an electrical distribution network having a line conductor carrying an electrical signal between a power source and a load, the system being capable of detecting series arcs, line-to-neutral arcs and line-to-ground arcs. The system includes a sensor coupled to the line conductor for monitoring the electrical signal and generating a sensor signal representing the electrical signal. The system generates an arc-indicative signal in response to the sensor signal having characteristics indicative of an arcing fault. The system can include a testing system in which a test wire is coupled to the sensor simultaneously with the line conductor and a test signal is periodically produced on the test line. The sensor simultaneously monitors the test signal and the electrical signal and produces a sensor signal representing both the test signal and the electrical signal when the test signal is present on the test line.

Abstract: An arrangement is provided for welding together current carrying members of an electrical distribution device that are made of similar conductive material. The arrangement includes an electron beam gun capable of generating an electron beam sufficient to penetrate and heat the material, thereby providing mixing of the material to form a joint which is constructed substantially of a portion of each of the current carrying members.

Abstract: An electrical isolation device is provided for use in an electrical distribution network having a plurality of branch circuits each defined by line and neutral conductors connected between a power source and a load, the line conductor being electrically connected to one of a plurality of line buses at an electrical distribution panelboard, the neutral conductor being electrically connected to a neutral bus at the electrical distribution panelboard. The isolation device includes a capacitance coupled between the line and neutral conductor of each of the branch circuits and is designed to provide a low impedance path for an arcing fault occurring on the line conductor of the branch circuit. The capacitance is sufficiently large to provide power factor correcting current.

Abstract: An electrical fault detector system detects electrical faults in an electrical distribution system by monitoring one or more conductors and producing an input signal representing one or more electrical signal conditions in the circuit to be monitored. This input signal is processed to develop a first signal representing the electrical current flow through the monitored circuit and a second signal representing signal components in a selected frequency range typical of arcing faults, and which exceed a predetermined threshold. The system also detects ground faults in the circuit being monitored.

Abstract: An apparatus for use in arcing fault detection systems within circuit breakers and which is adapted for automated production by top-down assembly. In one embodiment, the apparatus includes a circuit board and a two-piece sensing coil within a two piece housing with its center oriented horizontally relative to the circuit board. In other embodiments the sensing coil is one-piece and is either preassembled with a sensing bus and oriented horizontally or oriented vertically relative to the circuit board. Also included are several methods for making electrical connections to the circuit breakers.

Abstract: A circuit breaker unit having a backmold which can withstand horizontal axial forces, which cause deflection or bowing of the backmold. The circuit breaker unit comprises an enclosure, cradle and pultruded backmold. The pultruded backmold is molded with at least one horizontal rib adjacent a top end, a bottom end or an area therebetween to provide additional strength and support of the circuit breaker and field serviceable connections.

Abstract: The present invention provides an accessory module for monitoring and controlling the status of a circuit breaker. The accessory module attaches to the side of a circuit breaker and has a mechanism similar to the mechanism in a circuit breaker. The mechanism has multiple positions that correspond to multiple states of a circuit breaker. Actuators transform relatively large-scale motions of the mechanism into small-scale motions and transfers these to buttons on switches. Depressing these switches depending on the position of the mechanical assembly makes and breaks circuits that are in communication with a remote site. The invention provides a circuit board designed specifically to hold and locate the switches and actuators and provide tracings that can withstand high currents. The invention further provides a terminal plug having a pull tab which can be grasped to remove an otherwise inaccessible terminal plug.

Abstract: An arcing fault circuit interrupter testing method includes the steps of producing a simulated line to neutral arcing fault signal comprising a relatively large di/dt signal, applying the signal to a branch circuit, and producing an observable indication of operation or lack of operation of an arcing fault circuit interrupter in the branch circuit in response to the simulated line to neutral arcing fault signal. A test apparatus carries out the method.

Abstract: A switchboard for mounting and supplying electrical power to a plurality of circuit breakers has all the breakers are mounted on one side of a vertical power stack. The power stack has vertical buses to which the breakers are connected. Insulators and spacers provide air ventilation paths through the power stack. The main bus connecting members on the other side of the power stack from the breakers and are spaced apart vertically to allow for improved heat dissipation. By using vertical bus connectors, the bus connecting members may be connected to through bus connectors at any height on the back of the switchboard. The main bus connecting members are in a vertical chimney for improved heat dissipation. The circuit breaker at the highest location (the “A” phase) has the highest temperature and in the present invention, the main bus connecting member for the A phase is in the highest position to place it closest to the heat source and thereby improve the heat conduction away from the breakers.

Abstract: A system to detect arcing faults in an electrical distribution system with a line conductor connected to a utility power transformer. The system monitors the rate of change of electrical current in the line conductor and produces a signal which represents the rate of change. The system produces a pulse each time the rate-of-change signal exceeds a selected threshold, filters the rate-of-change signal and/or the pulses to substantially eliminate a signal or pulse which represents changes in the electrical current outside a selected frequency range, monitors the remaining pulses to detect when the number of pulses that occur within a selected time interval exceeds a predetermined threshold, and generates an arc-fault-detection signal in response to the occurrence of a number of pulses which exceed the threshold within the selected time interval.

Abstract: An assembly for auotomatically mating a plug terminal attached to the exterior of a circuit breaker with a receptacle terminal attached to the interior of a switchgear cell to provide secondary connections therebetween. The assembly includes a plug having a generally planar body partially defined by a surface and opposing surface. A plug terminal is supported by the opposing surface of the plug. A mounting bracket is slidably affixed to the opposing surface of the plug. The bracket has an aperture to allow the plug terminal to extend therethrough. The bracket is secured in a fixed position to the exterior of the circuit breaker. The position of the plug is automatically adjusted to provide proper alignment between the plug terminal and the receptacle terminal to form an electrical connection between the terminals which can be disengaged.

Abstract: An arcing fault protection system for a switchgear enclosure includes a switching device for rapidly diverting current from the source bus of an electrical distribution system in response to the detection of arcing faults in the system. The switching device, which may comprise a mechanical switch, a solid-state switch or hybrid device, quickly diverts current carried on the source bus to effectively extinguish arcing fault currents present in the distribution system, preventing the generation of gases at high pressures and/or temperatures so as to protect the switchgear equipment from damage.

Abstract: An alternating current sensing apparatus includes at least two coils, each having a plurality of turns of wire around a core which defines a linear axis. The coils are mounted in spaced relation on a support surface so as to define an intermediate space, and the coils are electrically coupled additively in series. The coils produce a detectable signal in response to an alternating electrical current passing through a conductor which extends through the intermediate space.

Abstract: A medium to high voltage load circuit interrupter and method for breaking the flow of electric current in a line having a load and a source. A main switch is connected in series with the line. A metal resistor having a positive temperature coefficient of resistivity (PTC element) is connected in series to the arcing switch, wherein the metal resistor and arcing switch are connected in parallel with the main switch. The main switch moves from the closed position to the open position prior to the arcing switch moving from the closed position to the open position. The circuit interrupter further includes an arc chute having a channel and electrically coupled to the arcing switch wherein the arcing switch is positioned within the channel when the arcing switch is in a closed position. In one embodiment, the PTC element is positioned on an insulator positioned between a ground and the main switch and an arcing switch. In another embodiment, the PTC element is positioned within a channel in the arc chute.

Abstract: The present invention provides an electrical power distribution system which contains a primary load-center (100) having a common data bus (124) that is adapted to provide two-way digital communication. A number of circuit breakers (120) are coupled to the common data bus (124). Each circuit breaker (120) has a first contact and second movable contact which is moved between a closed position and an open position by an actuator (216). The circuit breaker contains a microcontroller based control circuit (210), which controls the operation of the actuator (216) according to programmed instructions, which may be stored in a memory (234) contained in the circuit breaker or which are communicated to the circuit breaker over the common data bus (124). A status detection circuit (218) coupled to certain nodes within the circuit breaker provides status information about various contacts and current paths contained in the circuit breaker.

Abstract: An electrical isolation device for use in an electrical distribution network having a plurality of branch circuits each defined by line and neutral conductors connected between a power source and a load, the line conductor being electrically connected to one of a plurality of line buses at an electrical distribution panelboard, the neutral conductor being electrically connected to a neutral bus at the electrical distribution panelboard. The isolation device includes a filter coupled between a selected number of line buses and the neutral bus at the panelboard and is designed to provide a low impedance path for an arcing fault occurring on either of the selected number of line buses. In another embodiment, the isolation device is comprised of a filter coupled between the line and neutral conductor of a selected one of the branch circuits and is designed to provide a low impedance path for an arcing fault occurring on the line conductor of the selected branch circuit.

Abstract: A circuit breaker for interrupting the flow of electric current in a line includes a switch connected in series with the line, the switch having an open position and a closed position. At least one positive temperature coefficient resistivity element (PTC element) is connected in series with the line. A first magnetic coil is positioned around a yoke, for example, an iron core, and connected in parallel with the PTC element and a second magnetic coil is positioned around the yoke and connected in series with the line and the switch. A voltage limiting device, such as a metal oxide varistor, is connected in parallel with the at least one PTC element. An armature is pivotally mounted in relation to the yoke wherein the yoke and the armature form a magnetic circuit with the first magnetic coil and the second magnetic coil.