Abstract: An arc fault circuit interrupter includes separable contacts, an operating mechanism, a current sensor sensing current flowing through the contacts and outputting a sensed current, and a processor determining and storing peak values of the sensed current for plural half-cycles. The processor provides arc fault detection, determines whether a first predetermined plurality of half-cycles occur in succession and correspond to non-unity power factor, and responsively inhibits the detection for a first predetermined time, and whether a second predetermined plurality of half-cycles occur in succession, each with smaller peak amplitude than that of an immediately preceding half-cycle of like or differing polarity, and responsively inhibits the detection for a second predetermined time.

Abstract: An arc fault circuit breaker includes line and load terminals, separable contacts electrically connected between the terminals, a current sensor adapted to sense current associated with a load and flowing between the terminals and through the separable contacts. An arc fault detection circuit provides series arc protection and generates a trip signal responsive to the sensed current. The arc fault detection circuit collects a plurality of samples of the sensed current over plural line cycles, determines that the load is a dimmer-controlled load, determines a phase angle at which the sensed current begins conduction within one of the line cycles, and determines that the phase angle consistently moves in a forward direction or a reverse direction. If so, then series arc protection is responsively inhibited. An operating mechanism opens the separable contacts responsive to the trip signal.

Abstract: An arc fault circuit interrupter includes line and load terminals, separable contacts, a current sensor sensing current flowing between the terminals and associated with one type of load, and a first arc fault detection circuit generating a first trip signal responsive to the sensed current. A second arc fault detection circuit collects a plurality of sensed current samples for a current line cycle and also for a previous line cycle, determines a total current value from a peak current of the current line cycle samples, employs the total current value and some of the samples to determine the type of load, and generates a second trip signal responsive to the sensed current and the determined type of load. A trip circuit generates a third trip signal responsive to the first and second trip signals. An operating mechanism opens the contacts responsive to the third signal.

Abstract: A miniature circuit breaker includes separable contacts, an operating mechanism structured to open and close the separable contacts, a microprocessor including a thermal overload predictive function, and a shunt wire in series with the separable contacts. The shunt wire is structured to measure current flowing through the separable contacts for the thermal overload predictive function and an arc fault protective function.

Abstract: A leakage-current detection and interruption apparatus includes a plug adapted to receive an alternating current voltage, pairs of separable contacts adapted to receive the AC voltage from the plug, and an operating mechanism adapted to open and close the contacts. A power cord includes line and neutral power conductors adapted to conduct the AC voltage from the contacts to the load, a ground conductor, and two non-load carrying, non-ground conductors. One or both of the conductors do not shield one or both of the power conductors. A detection circuit is adapted to detect cord faults. The detection circuit includes a ground fault detection circuit having a current transformer with an opening through which the power conductors pass. The ground fault detection circuit cooperates with the non-load carrying, non-ground conductors to detect one or more of the cord faults and with the operating mechanism to interrupt the detected faults.

Abstract: An arc fault circuit interrupter includes a line terminal, a load terminal, separable contacts electrically connected between the line terminal and the load terminal, and a current sensor structured to sense current associated with the load and flowing between the line terminal and the load terminal and through the separable contacts. The sensed current includes a plurality of line cycles. An arc fault detection circuit is structured to provide series arc protection and to generate a trip signal responsive to the sensed current from the current sensor. The arc fault detection circuit collects a plurality of samples of the sensed current over the line cycles, determines a single current transient associated with energization of the load, and responsively inhibits the series arc protection. An operating mechanism is structured to open the separable contacts responsive to the trip signal.

Abstract: A circuit breaker includes separable contacts, an operating mechanism structured to open and close the separable contacts, and a trip mechanism. The trip mechanism includes a sensor structured to sense current flowing through the separable contacts, a processor cooperating with the sensor to determine a plurality of different trip conditions responsive to the sensed current, a nonvolatile memory operatively associated with the processor, and a trip actuator cooperating with the processor and the operating mechanism to trip open the separable contacts responsive to one of the different trip conditions from the processor. The processor is structured to save in and retrieve from the nonvolatile memory cause-of-trip information for the different trip conditions including the one of the different trip conditions.

Abstract: An arc fault circuit interrupter includes separable contacts electrically connected between line and load terminals, and a current sensor adapted to sense current flowing between the terminals and through the contacts. An arc fault detection circuit is adapted to collect a plurality of samples of the sensed current for a line cycle, determine a first slope of the sensed current at about a zero crossing of a line voltage, determine a magnitude of one of the samples at about the zero crossing, determine a second slope of the sensed current at another one of the samples having about the magnitude, with the first slope being opposite in polarity with respect to the second slope. The arc fault detection circuit calculates a difference between the slopes, and generates a trip signal as a function of the difference. An operating mechanism is adapted to open the contacts responsive to the trip signal.

Abstract: An arc fault detection circuit collects samples of sensed current, determines a peak current value from the samples for each line cycle, determines a hysteresis value for a compressor load as a function of differences between the peak current values, and generates a trip signal responsive to the sensed current and the hysteresis value. The circuit determines a difference value for each line cycle from the present peak current value less the previous peak current value, low pass filters the difference value to provide a low pass filtered value, determines a peak value from the low pass filtered value, determines that the absolute value of the low pass filtered value is less than a portion of the peak value and responsively saves the peak value, and determines the hysteresis value as a function of the saved peak value. An operating mechanism opens separable contacts responsive to the trip signal.

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: 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 circuit analyzer tests a power circuit including an earth leakage ground fault circuit interrupter, a receptacle, and a line, a neutral and a ground electrically connected between the circuit interrupter and the receptacle. The circuit analyzer includes a plurality of pushbuttons for inputting a plurality of test requests. A microprocessor outputs a plurality of test signals responsive to the test requests. A plurality of load circuits selectively provide a load between the line and the neutral responsive to one of the test signals. A display confirms tripping of the ground fault circuit interrupter responsive to the load, in order to determine if the neutral is electrically connected to the ground between the circuit interrupter and the receptacle.

Abstract: A circuit analyzer tests a power circuit including an earth leakage ground fault circuit interrupter, a receptacle, and a line, a neutral and a ground electrically connected between the circuit interrupter and the receptacle. The circuit analyzer includes a plurality of pushbuttons for inputting a plurality of test requests. A microprocessor outputs a plurality of test signals responsive to the test requests. A plurality of load circuits selectively provide a load between the line and the neutral responsive to one of the test signals. A display confirms tripping of the ground fault circuit interrupter responsive to the load, in order to determine if the neutral is electrically connected to the ground between the circuit interrupter and the receptacle.

Abstract: A pulsing apparatus for an electrical system includes line and neutral terminals structured to input a nominal alternating current line voltage, a timing mechanism or circuit for generating a timing signal having a duty cycle from the line voltage; a transformer for transforming the line voltage to a stepped up voltage having the duty cycle; load and load neutral terminals; and an output circuit for outputting a current at about the stepped up voltage to the load and load neutral terminals. The stepped up voltage is greater than the line voltage and less than a rated voltage of the electrical system. The stepped up voltage is adapted to identify an arcing fault in the electrical system. The duty cycle limits an average value of the current to less than about 4 mA to about 6 mA.

Abstract: An annunciation system which will detect the majority of failed breakers and indicate to the consumer when a breaker needs to be replaced, but does not put the consumer in an emergency situation where critical loads have lost power. The annunication system provides a visible and audible indication of the failure of a breaker to trip either as a result of fault current conditions or a test of a ground fault or arc fault circuit.

Abstract: A testing device for detecting and locating an arcing fault in an electrical system includes a detector circuit for detecting one or more characteristics of the arcing fault proximate the arcing fault and outputting a responsive signal. An annunciator speaker or display annunciates the responsive signal when the detector circuit is proximate the arcing fault, in order to locate the arcing fault in the electrical system.

Abstract: An arc fault/ground fault circuit interrupter for a power circuit includes a line terminal; a load terminal; and separable contacts electrically connected between the line and load terminals. An operating mechanism opens the separable contacts and has a closed position for closing the separable contacts. A trip mechanism cooperates with the operating mechanism to trip open the separable contacts. A ground fault protection circuit is operatively associated with the power circuit. An arc fault protection circuit is also operatively associated with the power circuit. A circuit tests the ground fault protection circuit, tests the arc fault protection circuit, and restores the operating mechanism to the closed position responsive to sequential activation of test and reset buttons.

Abstract: A protective relay determines frequency of an AC signal of an electric power system. The protective relay includes a circuit measuring the AC signal period between zero crossings to provide a measured period value. A microprocessor includes a random access memory having a five-element array, which collects five consecutive values of the measured period values. A microprocessor routine chooses a median from the measured period values and generally determines the frequency based upon the median. The median is ignored and the previously determined line cycle period is adjusted to determine the new line cycle period if: an absolute value of a difference between a last value of the measured period values and a previously determined line cycle period is not less than a predetermined value; and the last value of the measured period values is within the limits of the array.

Abstract: An improved test button assembly for use in a circuit breaker includes a frame and a button member, with the button member being pivotably mounted on the frame. A pair of microswitches are mounted on a printed circuit board that is disposed on the frame. The button member is alternately engageable with the two microswitches, with one of the microswitches being connectable with a ground fault protection circuit, and the other microswitch being connectable with an arc fault protection circuit. In an alternate embodiment, a common electrical contact is mounted on the button member, and a pair of contacts are mounted on the frame, with the common contact being alternately engageable with each of the contacts mounted on the frame. The contacts mounted on the frame are connected with the ground fault and arc fault protection circuits.

Abstract: A trip signal generator for an arc fault or ground fault trip unit includes two inputs electrically interconnected with the two outputs of arc fault and ground fault detection circuits. A second input is electrically interconnected with an anode of a semiconductor switching device, such as a triac or SCR, which drives a trip coil of a trip solenoid. A circuit monitors the outputs of a power supply and provides an output when the outputs of the power supply are operational. A trip logic circuit drives a gate of the semiconductor switching device when the outputs of the power supply are operational, when one of the two first inputs is active, and when the second input is inactive.