Abstract: A controller includes a memory that stores instructions and a processor that executes the instructions. The instructions cause the controller to execute a process that includes receiving sensor data from a first sensor and a second sensor. The sensor data includes a time-series observation representing a first activity and a second activity. The controller generates models for each activity involving progressions through states indicated by the sensor data from each sensor. The controller receives from each sensor additional sensor data including a time-series observation representing the first activity and the second activity. The controller determines likelihoods that the models generated a portion of the additional sensor data and calculates a pair-wise distance between each sensor-specific determined likelihood to obtain calculated distances.

Abstract: Examples of the present disclosure relate to a method for anomaly response in a system on chip. The method comprises measuring a magnitude of a transient anomaly event in an operating condition of the system on chip. Based on the magnitude it is determined, for each of a plurality of components of the system on chip, an indication of susceptibility of that component to an anomaly event of the measured magnitude. Based on the determined indications of susceptibility for each of the plurality of components, an anomaly response action is determined. The method then comprises performing the anomaly response action.

Abstract: A system and methods are provided for testing anode integrity during vehicle operation. In one example described, the system and methods allow for anode leak tests during vehicle operation based on a flow of hydrogen into a fuel cell, the flow of hydrogen into the fuel cell maintaining the vehicle power while the leak test is performed. The methods further allow for operational adjustments responsive to the leak test, which may include controlling the vehicle power to manage vehicle operations in the presence of a hydrogen leak in some instances.

Abstract: Detecting electrostatic discharge (“ESD”) events in a computer system, includes: determining, from an ESD detector installed in the computer system, that an ESD event has occurred; identifying a component of the computer system within a predefined proximity to the ESD detector as possibly affected by the ESD event; and notifying a user of the computer system of the component possibly affected by the ESD event.

Abstract: A method for detecting damage to a hollow shaft is disclosed. A sensor for transmitting and receiving a signal is positioned at an end face of the hollow shaft, a signal is transmitted and an echo of the signal is received, the signal propagation time from the time of transmitting the signal until receiving the echo is determined, and the signal propagation time is compared to a predetermined intended value, and with a warning being emitted in the case of a deviation.

Abstract: Systems and methods for dynamically defending a site from lightning strikes are provided. The systems and methods involve dynamically altering electrostatic fields above the site and/or dynamically intervening in lightning.

Abstract: A scanning probe for an industrial nondestructive evaluation (NDE) ultrasound or eddy current scanning system. The scanning probe gathers reflected waveform data indicative of internal characteristics of the test object. The scanning probe also includes a self-contained multi-axis position encoder that correlates both multi-dimensional probe underside translation and rotation motion across the test sample surface with the multi-dimensional spatial location on the test object surface. The position encoder compensates for probe rotation that would otherwise negatively impact probe position determination accuracy. A data acquisition system combines sets of positional and waveform data for processing by an NDE analyzer.

Abstract: An alarm system for alarming whenever there is a power leakage from an electronic device, includes a voltage decreasing circuit, a switch circuit and an alarm circuit. The voltage decreasing circuit receives a first voltage from a live wire output terminal and outputs a second voltage. The switch circuit outputs a control signal when the power leakage is detected. The switch circuit is electrically connected to a connection port. The connection port is electrically connected to the live wire output terminal and a neutral wire output terminal. The alarm circuit receives the control signal and alarms. If there is power leakage from the electronic device, the first voltage from the live wire input terminal flows into the ground wire input terminal via the electronic device; the switch circuit turns on and the alarm circuit is closed to alarm.

Abstract: A method and apparatus for detecting and preventing electrically induced fires in a gas tubing systems constructed of Corrugated Stainless Steel Tubing (CSST) and Gas Appliance Connectors (GAC). The system of the present invention may include one or more energy detection schemes to detect electrical energy surges on the gas line. When such a surge is detected, the control circuitry of the present invention causes an electric main gas valve de-energize into a closed position. In addition, the system of the present invention further includes a residual gas dispersal system that automatically vents the residual downstream gas pressure remaining in the gas tubing system after the closure of the main gas valve.

Abstract: An intelligent electronic device (IED) has enhanced power quality and communications capabilities. The power meter can perform energy analysis by waveform capture, detect transient on the front end voltage input channels and provide revenue measurements. The power meter splits and distributes the front end input channels into separate circuits for scaling and processing by dedicated processors for specific applications by the power meter. Front end voltage input channels are split and distributed into separate circuits for transient detection, waveform capture analysis and revenue measurement, respectively. Front end current channels are split and distributed into separate circuits for waveform capture analysis and revenue measurement, respectively.

Abstract: The present invention relates to a device and method for displaying the lifecycle of a surge protection device, and more particularly to a device and method for displaying the lifecycle of a surge protection device, which detects an increase in leakage current according to a deterioration in performance of the surge protection device in order to provide notice of a replacement time for the surge protection device. According to the present invention, it is possible to for a user to provide notice of a replacement time by displaying the lifecycle of a surge protection device (SPD) to the outside. Additionally, as another effect of the present invention, it is possible to confirm an amount of leakage current flowing into the ground of the SPD and whether the SPD is properly installed on a ground line by using a current and ground state detecting sensor.

Abstract: Power transfer over power lines is indicated using a controller to short power lines briefly near the end of the positive portion of the alternating voltage cycle of a distant power generation source using a silicon-controlled rectifier thereby creating current pulses from the voltage produced by that source and at a frequency consistent with the source's electric system frequency. The pulse can be detected and measured on other parts of the same circuit using a probe. The controller and probe may be used for locating cables in the same electrical circuit, sorting particular cables in the same circuit from others cables, verifying the condition of cables, determining the source and load feeds on the primary side of a transformer from the low side of the transformer, locating unwanted ground faults, and determining the portion of the electrical load provided by each of plural generation plants.

Abstract: An indication circuit is used on a motherboard. First and second pins on the motherboard output different signals corresponding to different power-on self-test errors. The indication circuit includes first to third electronic switches, first and second light-emitting diodes, and first to fifth resistors. When different errors occurred during power-on self-test, different signals are output from the first and second pins on the motherboard, such that to make the first and second light-emitting diodes activated or deactivated. As a result, the indication circuit can indicate different errors when the motherboard is performing power-on self-test.

Abstract: A system and a method is provided for the detection and capture, and in particular for an ultra high speed detection and capture, of transients in input voltages by an intelligent electronic device. The system and method detects transients for input voltages in either phase to phase or phase to neutral measurements and permits a user to set threshold levels for detecting transients in input voltages. In an embodiment, the system and method further provides a field programmable gate array as a controller for managing transient detection. The field programmable gate array includes a state machine for determining the state of the sampled signal with respect to a threshold level at a specified waveform sample period.

Abstract: An electrical circuit identification means is revealed. The electrical circuit identification device includes a signal generator connected directly to an AC power socket and a signal receiver set in a power control panel. The signal generator blocks a half cycle of sine waves and produces a short off-and-off signal at an interval. The signal receiver includes a signal sensor receiving signals from the signal generator and connected to both a control voltage divider and a signal strength switch for modulating and amplifying signals received by the control voltage divider, and a signal integration module that is connected to the signal strength switch and a microcontroller for outputting digital signals with different waveform. An identification system in the microcontroller cross checks the digital signals and the identification accuracy is determined according to the position of a light lit up in an indicator light module.

Abstract: A lightning detection system is presented. The lightning detection system includes a plurality of sensing devices configured to generate sensor signals representative of one or more working state parameters of an object. The lightning detection system further includes a lightning signal processing subsystem configured to combine the sensor signals representative of the one or more working state parameters received from the plurality of sensing devices to generate a composite signal, extract noise signals from the composite signal, and compare the extracted noise signals with one or more lightning signal profiles to determine existence of lightning noise signals in the extracted noise signals, wherein the lightning noise signals are induced in the sensor signals in response to a lightning strike on the object.

Abstract: An apparatus and method for protecting against electrocution hazards that arise when an appliance is electrically connected to a miswired single-phase AC electrical source which includes an energized ground lead are described. The apparatus includes one or more sensors that detect electrical energy in the ground lead combined with a miswiring condition in the hot and common leads. A tester embodiment is also illustrated. The method includes the steps of detecting if the putative ground of the electrical source is energized and whether the hot and common leads are reversed.

Abstract: An arrangement that includes a transmitter unit and a receiver for locating a wire or a circuit interrupter associated with a selected branch circuit of a power distribution system. The transmitter is electrically interconnected with the selected branch circuit and produces a sequence of current pulses in a branch circuit that is to be traced to locate an associated circuit interrupter. Each current pulse is of a predetermined duration, a predetermined rise time, and a predefined fall time, which in one embodiment is equal to the current pulse rise time. The receiver is a handheld unit that is positioned in close proximity with the various circuit interrupters of the power distribution system and provides an indication that the desired wire or circuit interrupter has been located upon detecting current pulses that are with a predefined pulse duration, pulse separation and amplitude.

Abstract: Detection of fault occurrences within a power distribution system. A transient detector and fault classification system (10) implements an algorithm that detects transients which may result from the occurrence of a fault in the power distribution system. The system includes a detection module (18) which processes a set samples obtained from electrical waveforms propagated of through the power distribution system and appear to be statistically anomalous compared to other sample data. This is done using an adaptive detection algorithm that is applied when large changes occur in a waveform over a relatively short period of time. The identified samples are then provided to a signal classifier module (20) which processes sets of samples to classify a transient they represent as a likely fault occurrence or some other type of anomaly which is likely not a fault occurrence.

Abstract: Described are methods and apparatuses, including computer program products, for detecting lightning activity. Waveform data indicative of lightning activity is received by a waveform sensor from one or more signal converters. The waveform data comprises a group of electromagnetic waveforms. The waveform data is filtered by a processor to remove noise frequencies. One or more uncompressed portions of the waveform data are transmitted to a processing server. Digital filter data based on the one or more uncompressed portions of waveform data are received from the processing server. One or more frequencies are removed from the waveform data based on the digital filter data. The waveform data is compressed. The compressing includes selecting one or more points on a waveform, wherein the one or more points are above a predetermined threshold. The compressing includes determining an inflection of the selected points based on a predefined algorithm.

Abstract: Systems and techniques for processing signals representative of sound for conveyance to the auditory system of a subject based on the identity of an input device. In one implementation, a method includes identifying an input element to an audiological system that conveys sound information directly to a subject's auditory system, automatically setting parameters for processing the signal based on the identity of the input element, and processing the signal in accordance with the processing parameters. The input element is configured to generate a signal representative of sound.

Abstract: The disclosed power distribution system regulates the transfer of energy from a source 1 to a load 3. Source Controller 5 on the source side closes Disconnect Device 7 and monitors the transfer of a pulse or “packet” of energy to the load side. A Load Controller 9 on the load side communicates the amount of energy received at the load back to the source controller via Communication Link 11. If it is confirmed that the energy received on the load side corresponds to that sent by the source side, another energy packet is sent. If the energy received does not correspond with that sent by the source side, energy transfer is stopped, indicating a system fault or safety hazard. The energy content of a single packet is kept small, such that if it is not properly delivered, it can not cause damage to equipment or harm personnel.

Abstract: An instrument (1) and a method for measuring pulses of partial electrical discharges in an electrical system comprise data processing means (5) operatively associated both with an input stage (2), able to receive an analogue signal (3) representing said pulses and to provide a digital representation of the entire wave form of the pulses, to receive said digital representation, extract the value of predetermined parameters relating to the wave form of the pulses and transfer to and output stage (4) a processed digital signal comprising said values, the processing means (5) being able to operate substantially in real time, i.e. with no need for a memory for the intermediate storage of the data.

Abstract: A method and apparatus for ground bounce and power supply bounce detection in devices have been disclosed. In one case one input to a differential amplifier is coupled to a reference voltage and another input to the differential amplifier is coupled to a measurement point and the output of the differential amplifier is coupled to a flip flop. The flip flop has an output indicating when a bounce threshold is exceeded.

Abstract: A power management system includes a battery pack having a battery controller and includes an adapter operable for charging the battery pack and powering a system load. The adapter generates a power recognition signal indicative of a maximum adapter power and receives a control signal. The battery controller in the battery pack receives the power recognition signal and generates the control signal to adjust an output power of the adapter according to a status of the battery pack and a status of the system load.

Abstract: An arrangement that includes a transmitter unit and a receiver for locating a wire or a circuit interrupter associated with a selected branch circuit of a power distribution system. The transmitter is electrically interconnected with the selected branch circuit and produces a sequence of current pulses in a branch circuit that is to be traced to locate an associated circuit interrupter. Each current pulse is of a predetermined duration, a predetermined rise time, and a predefined fall time, which in one embodiment is equal to the current pulse rise time. The receiver is a handheld unit that is positioned in close proximity with the various circuit interrupters of the power distribution system and provides an indication that the desired wire or circuit interrupter has been located upon detecting current pulses that are with a predefined pulse duration, pulse separation and amplitude.

Abstract: An exemplary surge current alarm circuit includes a detecting circuit to detect a surge current and convert the surge current into a digital signal with a pulse width corresponding to a duration of an over value part of the surge current when the surge current is over a limitative current value; a processing circuit connected to the detecting circuit to receive the digital signal and generate an alarm signal when the pulse width of the digital signal is over a limitative time; and an alarm circuit connected to the processing circuit to give an alarm upon receiving the alarm signal from the processing circuit.

Abstract: Apparatus includes an arc wave generator for testing an arc fault circuit interrupter (AFCI) for use in a test system for testing whether or not an arc fault circuit interrupter (AFCI) is operating normally, in which a false arc is generated for use in testing the arc fault circuit interrupter (AFCI). The arc wave generator includes a rectifier which receives a commercial power source as an input source and rectifies alternating-current voltage of the commercial power source to generate a rectified signal. A drop resistor drops the voltage of the rectified signal to generate a voltage-dropped signal. A mono-stable multivibrator adjusts a voltage level and a pulse width of the voltage-dropped signal and generates a pulse signal which is used to generate a false arc for testing the arc fault circuit interrupter (AFCI). Thus, a false arc is generated with a simple circuit to accurately test the actions of the arc fault circuit interrupter (AFCI).

Abstract: Methods, devices, and systems for monitoring a number of recurrent activities of an individual are disclosed. One method for monitoring a recurrent activity of an individual using activity windowing includes recording a number of sensor activations of at least one sensor, determining a number of peaks in the number of sensor activations, defining one or more time frames based upon the location of at least one of the number of peaks in the time period, and applying a rule associated with a threshold number of activations, where the rule is applied to at least one particular time frame in order to determine whether to initiate an action.

Abstract: Aspects of the invention provide apparatuses, methods, and systems that support measuring and conveying energy consumption by an electrical device. An apparatus includes an energy sensor that measures an incremental energy value consumed by an electrical device. Apparatus obtains the incremental energy value, accumulates an energy usage measurement in accordance with the incremental energy value, provides requested information about energy consumption of the electrical device in response to a request from a network controller, and adjusts the energy usage measurement in accordance with the requested information. The total energy consumption may be partitioned into at least one energy component, in which the at least one energy component corresponds to the energy consumption of the electrical device during an associated time interval. A network controller may use the energy consumption information to determine a new set temperature for a thermostat unit that instructs the device control logic.

Abstract: A method and apparatus for ground bounce and power supply bounce detection in devices have been disclosed. In one case one input to a differential amplifier is coupled to a reference voltage and another input to the differential amplifier is coupled to a measurement point and the output of the differential amplifier is coupled through a diode to a sample and hold circuit which is coupled to an analog to digital converter.

Abstract: An apparatus for detecting the power state of a circuit breaker switch is disclosed. The apparatus comprises a detector circuit, a processor and an indicator. The processor is coupled to the detector circuit. The indicator is coupled to the processor. In operation, the detector circuit senses an electronic signal at the circuit breaker switch and transmits a signal to the processor. The processor then transmits a signal to the indicator indicating the power state and location of the circuit breaker switch.

Abstract: A system for improving Field Replacement Unit (FRU) isolation in memory sub-systems by monitoring Voltage Regulator Module (VRM) induced memory errors. A comparator compares the output voltage coming from the VRM to memory. If the comparator detects a VRM output voltage transient that is outside a rated threshold, then a counter is increased by one. If the counter exceeds a count threshold, a VRM error is posted. If a memory failure occurs within a predetermined period of time, then the VRM error pinpoints the VRM output voltage transient as being the likely cause of the memory failure.

Abstract: A system and method are provided for determining an expected life of an electric surge protection component. The system and method monitors preferably each surge that an electric surge protection component experiences. Each surge is measured to determine magnitude and duration, and a cumulative surge measurement history is maintained for each component. Based upon an analysis of the cumulative surge measurement history, an expected life of the component is determined, and an end user is alerted at or preferably near an end of the expected life of the device.

Abstract: A method for rapidly extracting data file samples with an a signal monitor and an automatically adjusted decimation ratio is provided to solve the long-standing problems caused by large data files and small buffers by reducing a large data segment to a smaller, more manageable size automatically so that a lower resolution version of the data segment will be loaded into a fixed-size small buffer in the computer's working space buffer for further data editing. In accordance with the methods of this invention, the segment size will vary during the operation of a means for zooming-in and the decimation ratio is updated and adjusted automatically based on the variation of segment size. The present invention insures that the best resolution of the data segment will be achieved when fitting the varying large size data segment into the fixed small size buffer.

Abstract: A tester for an arc fault circuit interrupter that can selectively simulate and apply electrical arc faults and nuisance loads to at least one device under test (DUT). The tester includes a power supply, a test controller, and test circuitry coupleable to a DUT. AC power input is provided to the DUT and the power supply, which regulates the AC power input to a DC level for powering the test controller. The test circuitry full wave rectifies AC current returning from the DUT, and the test controller controls a switch in the test circuitry. When the switch is on, the AC current flows through the DUT, the full wave rectifier, the load, and the switch to ground. To simulate an arcing condition, the test controller turns the switch on and off at random intervals. To simulate a nuisance load condition, the test controller turns the switch on and off at periodic intervals. In this way, proper operation of the DUT can be verified under both arcing and nuisance load conditions.

Abstract: A Very Local Area Network (VLAN) comprises a power strip device having an electrical connector for connection to an AC power supply line and one or more surge protectors and line filters. Multiple electrical power outlet sockets receive plugs from electrical appliances. A communications pathway interconnects the multiple electrical power outlet sockets to enable communication between appliances connected to the sockets. Electronics configure appliances as they are connected to the sockets to enable them to communicate over the communications pathway.

Abstract: A protection device for a communication circuit that includes a sensor monitoring a protection device parameter and an indication module coupled to the sensor. The indication module generates an indication output as a function of the protection device parameter indicating a protection device event. The indication module receives power from an indication power source separate from the telecommunication signal. Also a method for protecting a telecommunication signal with a protection device including sensing a protection device parameter indicating a protection device event. The method also includes powering an indication module from an indication power source that is separate from the telecommunication signal. The method further includes generating an indication output from the indication module as a function of the protection device parameter indicating the protection device event.

Abstract: A fault diagnosis circuit of the present invention includes: LED indicating units 3a, 3b, and so forth; current detecting circuits R1 and Q1 for detecting a flowing current by flowing a short-time pulse of a current through the LED indicating units 3a, 3b, and so forth based on pulses generated by a pulse generating circuit 7; comparing circuits 8 and 9 for comparing a current value detected by the current detecting circuits R1 and Q1 with their respective threshold values to judge a disconnection and a short-circuit; and retaining circuits 10 and 11 for generating a signal and retaining the signal when the current value is judged as being smaller and larger than the respective threshold values as a result of comparisons by the corresponding comparing circuits 8 and 9. Thus, it is possible to indicate a fault in an LED indicating light to the outside while making the turning ON of an LED unperceivable.

Abstract: In order to improve detecting accuracy in a gas leak detection for a fuel cell, in a gas leak detection method for a fuel cell having a solid polymer electrolyte membrane sandwiched by an anode and a cathode, an output voltage is measured in an activated over-potential region in a state in which the pressure of fuel gas which is supplied to the anode is maintained higher than the pressure of gas which is supplied to the cathode, and a gas leak is determined to exist when the output voltage is lower than a predetermined pressure value.

Abstract: A flap to be identified is caused to move over the whole of its angular range of travel. The number of motor steps is counted during this movement, and the number of steps counted is compared with at least one pre-recorded information item corresponding to a particular flap or type of flap. The method is applicable to the checking of the correct fitting of actuator housings in an air-conditioning installation, or to the allocation of addresses to actuators connected to an information bus.

Abstract: An electrical safety monitor (20) includes a housing (50) with a display face (70) and a securing section (54) that connects with an electrical panel (62). Electrical circuitry (30) is contained in the housing (50). The electrical circuitry (30) communicates with electrical lines (L1, L2, L3, GND) of the panel (62), and defines high impedance electrical paths between pairs of electrical lines (L1, L2, L3, GND). Each high impedance path includes a positive light emitting diode (D1, D2, D3, D4) arranged to draw current from a line carrying a positive electrical energy potential and a negative light emitting diode (D5, D6, D7, D8) arranged to draw current from a line carrying a negative electrical energy potential relative to the positive electrical energy potential. The positive and negative light emitting diodes are disposed on the display face (70) of the housing (50). Each light emitting diode produces light responsive to current flow in a high impedance path that includes the light emitting diode.

Abstract: An apparatus to indicate a state where a communication device connected to a communication wire and a power line is protected from a surge current. A toroidal coil picks up a rapid increase of current caused by a rapid increase of voltage that occurs in the communication wire and/or the power line. The toroidal coil is connected to the current detecting unit. The current detecting unit converts the current from the toroidal coil into a voltage and supplies it to a switching circuit. The switching circuit turns on an indicator light circuit to light up an LED of the indicator light circuit.

Abstract: A multi-functional hybrid contactor has a motor protection function against an abnormal state in addition to the starting, running and stopping of the motor, the same effect as the case that an electronic motor protection relay (EMPR) is connected in parallel can be obtained with only one multi-functional hybrid contactor. Also, the size of the product is much reduced compared to the case that the electric motor protection relay (EMPR) is connected in parallel, and its cost can be reduced. In addition, since the semiconductor switch is turned on only in the initial stage of starting and stopping, the rated current capacity and size of the semiconductor switch can be considerably reduced compared to the conventional soft starting method in which the semiconductor switch is used for controlling of all of starting, running and stopping.

Abstract: A method and device for in-use detecting low cranking strength of a combustion engine battery during engine starting, based on integrating changes in battery voltage specifically during engine starting, from the time the electro-mechanical starting load is initially applied to the battery, and logically analyzing values of the integrated changes in battery voltage during engine starting, for determining whether or not there is an initial stage of developing low cranking strength of the battery.

Abstract: A device is provided which allows a personal computer user to monitor the operational parameters of the central processing unit's cooling fan. This device, called the CPU cooling fan speed monitor, characterizes the normal operating speed range of the CPU fan and the fan speed and provides warnings of improper fan speed. The fan speed monitor is a microcontroller-based device which has two principle modes of operation: the characterization mode; and the monitor mode. In the characterization mode, the fan speed monitor determines the “normal” operating speed range of the cooling fan. In the monitor mode, the fan speed monitor provides audible and visual indication of the operating speed of the CPU cooling fan.

Abstract: Systems of monitoring electric arcs substantially eliminate alternating current fundamentals and harmonics from monitored arc signatures. Such systems phase shift, delay or otherwise store a representation of the alternating current fundamental and harmonics, and substantially purge such alternating current fundamental and harmonics from the arc signatures with the stored representation of such alternating current fundamental and harmonics, while substantially preserving chaotic arc signature components. Electric arcs are then monitored from such purged arc signatures. Imperfections in such purging are detected and corrected for a provision of detectable arc signature components free of fundamentals and harmonics that could cause malfunction and false alarms.

Abstract: A power surge detection device is disclosed to investigate if there is any power surge occurring to a main processor in a computer system. When the width or frequency of power surges detected jeopardize the normal operation of the computer system, an alerting signal, for example, an interrupt signal or a power management signal, is sent to the main processor to intervene in the normal operation of the computer system so as to avoid the power instability period.

Abstract: A method of establishing a state of an encoder, and an encoder having a state assessment device that includes the steps of generating at least one analogue signal whose amplitude is changed in response to movement between an encoding disc and a detector, generating at least one pulse signal on the basis of the analogue signal by a comparator device, and assessing the amplitude of the analogue signal. The method further includes generating a first status signal on the basis of the amplitude assessment, and generating a second status signal on the basis of one or more of the pulse signals.

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.