Modular circuit protection devices and configurable panelboard systems include arc-free operation, thermal management features providing safe operation in hazardous environments at lower cost and without requiring conventional explosion-proof enclosures and without entailing series connected separately provided packages such as circuit breaker devices and starter motor contactors and controls.

Disclosed herein are various embodiments of devices and related methods for detecting an electrical arc event using a motor management relay and for suppressing the electrical arc event. The motor management relay may incorporate an optical arc-flash sensor configured to detect an optical event. Control logic may analyze the optical event and determine whether the optical event corresponds to an electrical arc event. When an electrical arc event is detected an instruction may be issued via a control port in communication with the control logic to implement a protective action. According to various embodiments, a plurality of sensors for monitoring electrical characteristics of a motor may also be in communication with the control logic. Input from the sensors may be analyzed in order to determine whether the optical event corresponds to an electrical arc event.

A modular circuit breaker includes a module assembly coupled to a primary assembly. The primary assembly includes a primary housing, separable contacts disposed therein, a first terminal conductor electrically connected to one of the separable contacts, a conductive tab electrically connected to another one of the separable contacts and which extends outward from a first end of the primary housing, an operating mechanism disposed in the primary housing for selectively opening and closing the separable contacts, and a trip mechanism disposed in the primary housing cooperative with the operating mechanism to trip open the separable contacts. The module assembly includes a module housing having a second terminal conductor positioned therein and electrically connected to the conductive tab, a third terminal conductor structured to be electrically connected to a neutral conductor of a load, and a fourth terminal conductor structured to be coupled to a neutral bus.

A reverse fault current interruptor (RFCI) may be employed in one or more locations in an electrical power system. In one example, an RFCI may be installed in a combiner box of a solar power system. The RFCI may include a reverse current detector and a circuit protector such as a circuit breaker, operable in combination to clear a line-line fault in the combiner box. The RFCI enables a reduction of incident energy levels through detection of a reversal in a fault current characteristic of some DC power systems, where a traditional overcurrent protection device (OCPD) (e.g., fuse, breaker) may not trip in the same period of time.

A circuit for a circuit interrupter is provided. The circuit may in include a first SCR configured to receive a first trigger signal at a gate of the first SCR, a second SCR configured to receive a second trigger signal at a gate of the second SCR, and a third SCR configured to receive a third trigger signal at a gate of the third SCR. A cathode of the first SCR may be connected to an anode of the third SCR. A cathode of the second SCR and a cathode of the third SCR may be connected to a ground. Methods of operating a circuit interrupter and a circuit are also provided.

Arc Fault Circuit Interrupter (AFCI), Ground Fault Circuit Interrupter (GFCI) or AF/GF circuit breakers which may optionally have relatively small or compact bodies that have shaped neutral busbars and/or load terminals with an arm that extends through a window of a current transformer in a circuit breaker housing. The neutral busbar and/or load terminal can have a rigid or semi-rigid shaped body with a first segment that extends through the window of the current transformer and a second segment that extends behind the first segment about a printed circuit board. A plug-on, pigtail or bolt-on neutral can engage an electrical pad of the neutral busbar.

A protective device including: a plurality of line terminals and a plurality of load terminals a circuit interrupter including a solenoid and a set of interrupting contacts that connect at least one line terminal and at least one load terminal in a reset state and disconnect the at least one line terminal and the at least one load terminal in a tripped state; a voltage detection element configured to detect voltage across the plurality of line terminals and generate a line voltage rejection signal when greater than a predetermined overvoltage; a reset assembly including a reset button and a reset switch operatively coupled to the reset button; and a reset prevention mechanism configured to prevent the circuit interrupter from entering the reset state when the reset signal is absent.

There is a need to monitor and control the state of relays and circuit breakers within power distribution systems. The monitoring of a relay state, i.e. open or closed, is often performed by applying a monitoring signal to sensing contacts added to the relay. Manufactures of such systems have chosen many different voltages for their own. monitoring systems making it difficult to interconnect dissimilar monitoring systems. A signal conditioning circuit is provided that can cope with a large input voltage range and can be configured to allow may items of equipment(which may be new item or legacy items) to be connected to a controller.

A short circuit current detection device for a medium voltage or high voltage switchgear includes: a reed contact; and a holder for holding the reed contact, the holder being mountable with a defined orientation to a conductor of the switchgear. At a location where the holder is mounted, the conductor has a longitudinal axis. The conductor enables a current to flow through the conductor in a direction of the longitudinal axis. The holder positions the reed contact with respect to the longitudinal axis such that when a magnitude of the current flow through the conductor exceeds a threshold current value the reed contact closes.

A module for detecting an electrical fault includes a housing; a first conductor and a second conductor; a first measurement toroid, positioned around the first conductor and around the second conductor, for measuring a differential current flowing between the first and second conductors; a second measurement toroid, positioned around the first conductor, for detecting an electric arc signal flowing through this conductor; a relay; an electronic processing circuit configured to switch the relay according to the current measured by the measurement toroids. The measurement toroids are aligned with one another and the first toroid takes the shape of an elongated tube and allows the differential protection to operate with its own current.