Abstract: An electrical switching apparatus includes a first terminal, a second terminal, a neutral conductor, separable contacts electrically connected between the terminals, an operating mechanism to open and close the contacts, a fused varistor electrically connected between the first terminal and the neutral conductor; and a trip mechanism including a trip coil cooperating with the operating mechanism to trip open the contacts. A second varistor is electrically connected in series with the trip coil between the first terminal and the neutral conductor. A thyristor is electrically connected in parallel with the second varistor. An overvoltage detection circuit is electrically interconnected with and causes the thyristor to energize the trip coil and cause the trip mechanism to trip open the contacts responsive to overvoltage between the first terminal and the neutral conductor.

Abstract: An electrical switching apparatus includes a first terminal, a second terminal, a neutral conductor, separable contacts electrically connected between the terminals, an operating mechanism to open and close the contacts, a fused varistor electrically connected between the first terminal and the neutral conductor; and a trip mechanism including a trip coil cooperating with the operating mechanism to trip open the contacts. A second varistor is electrically connected in series with the trip coil between the first terminal and the neutral conductor. A thyristor is electrically connected in parallel with the second varistor. An overvoltage detection circuit is electrically interconnected with and causes the thyristor to energize the trip coil and cause the trip mechanism to trip open the contacts responsive to overvoltage between the first terminal and the neutral conductor.

Abstract: A fail-safe ground fault circuit interrupter includes separable contacts; operating mechanism; and GF trip circuit including analog GF circuit having power supply input, and a number of: GF current transformer, first resistor in series with the GF CT, capacitor in parallel with this series combination, and second resistor between the power supply input and a common connection point between the first resistor and the capacitor, trip actuator cooperating with the OM, and zener diode including cathode interconnected with the power supply input and anode interconnected with the trip actuator, trip solenoid cooperating with the OM, bi-directional light emitting diode, and resistor in series with the LED, this series combination in parallel with the trip solenoid, and first silicon controlled rectifier cooperating with the OM, and second SCR cooperating with the OM, the second SCR in parallel with the first SCR.

Abstract: A circuit breaker includes a test circuit having one or two indicators, an arc fault signal generator, and first and second test switches. A first indicator is electrically connected in series with the first test switch. This series combination provides a first alternating current signal to the arc fault signal generator, which provides an arc fault signal to an arc fault trip circuit, in order to trip open separable contacts in response to closure of the first test switch. The series combination of the second test switch and the second indicator provides a second alternating current signal to a ground fault trip circuit, in order to trip in response to closure of the second test switch. The indicators provide a visual indication of failure of the arc fault or ground fault trip circuits to trip in response to closure of the first or second test switches, respectively.

Abstract: A receptacle interrupts a power circuit including a glowing contact and a gas, such as hydrogen chloride, carbon dioxide, carbon monoxide or a combination of those gases, associated with the glowing contact. The receptacle includes a set of separable contacts for interrupting the power circuit, an operating mechanism controlling the set of separable contacts, and a trip mechanism, such as a trip coil, cooperating with the operating mechanism to open the set of separable contacts in response to a trip signal. A gas detector detects the gas and outputs a gas concentration signal based upon a level of the gas. A microprocessor outputs the trip signal responsive to the gas concentration signal whenever a predetermined concentration level of the gas is detected.

Abstract: Apparatus for protecting a two-line electric power distribution system includes a circuit breaker pole in each line. Each pole includes a fault detector generating a fault signal in response to either an arc fault or a ground fault in the protected line, and a trip unit responsive to the fault signal. Each trip unit includes a trip coil and an SCR connected in series at a node with the trip coil connected to the neutral conductor and the SCR connected to the associated line conductor. A jumper connects the two nodes together directly without electrical isolation so that a fault signal from either detector energizes both trip coils to open both poles in response to an arc fault or a ground fault in either line, even if one of the line conductors is not energized.

Abstract: A receptacle interrupts a power circuit including a glowing contact and a gas, such as hydrogen chloride, carbon dioxide, carbon monoxide or a combination of those gases, associated with the glowing contact. The receptacle includes a set of separable contacts for interrupting the power circuit, an operating mechanism controlling the set of separable contacts, and a trip mechanism, such as a trip coil, cooperating with the operating mechanism to open the set of separable contacts in response to a trip signal. A gas detector detects the gas and outputs a gas concentration signal based upon a level of the gas. A microprocessor outputs the trip signal responsive to the gas concentration signal whenever a predetermined concentration level of the gas is detected.