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 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: An integrated protection system for an electrical distribution system including a panelboard for receiving power from a utility source and distributing the power to a plurality of branch circuits each having line and neutral conductors for delivering the power to a load. The integrated protection system comprises a plurality of arcing fault detectors and line interrupters attached to positions in the panelboard. The arcing fault detectors detect the occurrence of an arcing fault in either of the branch circuits, while the line interrupters disconnect the load from the power source in response to the detection of an arcing fault in either of the branch circuits. The line interrupters and arcing fault detectors may comprise separate modules, each being connected to one of the positions in panelboard or being attached externally to the other module.

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: The invention provides a mounting frame structure for association with a preformed aperture in a wall and for recessed mounting of a speaker or camera having a housing. The frame structure includes a one-piece, unitary frame body having an open central region for receiving therethrough body portions of the housing. The frame body has a flattened perimeter region and apertures individually located in the perimeter region. The frame structure also includes a shoulder region upstanding rearwardly from and extending substantially about the perimeter region. A mounting flange upstands rearwardly in a perpendicular direction from the perimeter region. The mounting flange has a generally flat shape and at least one aperture therethrough so that the mounting flange abuts and secures to a stud or cross-member of the wall. Optionally, the frame structure is utilized in an assembly with a mounting bracket for the camera or speaker and a cover plate thereover.

Abstract: Apparatus for simultaneously applying two independent forces to the contact blades of a movable contact assembly. The contact assembly has three contact blades joined at the base. The circuit breaker mechanism exerts a closing force through a blade carrier to the center blade which in turn exerts a closing force on the outer main blades. To increase the contact force on the outside main blade contacts without increasing the contact force of the center blade contact and without changing the relative distances between the blade carrier and the main blade contacts and center blade contacts, a compression spring is positioned between each main blade and the blade carrier.

Abstract: A circuit breaker having an electronic fault sensing and trip initiating unit which provides increased versatility and ability to coordinate the circuit breaker with other interrupting and protective devices in a wide variety of electrical distribution systems. Electronic circuits and components are provided to vary the ampere rating of the breaker, to adjust current carrying capacity, to provide a long time delay trip, a short time delay trip and an instantaneous trip depending on the amplitude of high fault currents, to provide a ground fault trip, to shorten or lengthen the trip time for short time delay faults and for ground faults, and to provide shunt trip capability. The tripping mechanism is magnetic and mechanical, and includes a plunger movable between a trip and non-trip position controlled by an electronic switch in the electronic circuitry, and a toggle mechanism which is unlatched by the plunger when it moves to the trip position.

Abstract: A multi-pole circuit breaker includes a wide toggle shaft which spans all of the poles of the breaker and which is electrically neutral. The lower links of the toggle mechanism are made of phenolic or other insulating material which thus electrically insulates the wide toggle shaft spanning all of the poles of the breaker and makes the toggle shaft electrically neutral. A plurality of short toggle springs may therefore be connected between the wide toggle shaft and a handle arm of corresponding width. The plurality of short toggle springs provide as much tripping energy as the longer single or double toggle springs of prior art circuit breakers in which the springs are clustered together in alignment with one pole of the breaker to which they are electrically connected and whose polarity the toggle springs in such prior art breakers accordingly take.