Abstract: A modular surge suppression system for a traffic cabinet. The system comprising a surge suppression module and a modular adapter connected to the circuitry in the traffic cabinet. The modular adapter being configured to connect with the surge suppression module.

Abstract: The present invention provides a signal connection installation including a signal connection device connected to a power fuse holder, in which the power fuse holder holds a power fuse cartridge which carries a supply of mains electrical power in use and in which a conductive component of the signal connection device makes electrical contact with a conductive component of the power fuse cartridge wherein the signal connection device is releasably secured to the fuse holder and the signal connection device includes a signal path interconnecting the mains supply and a communication signal connection, which signal path includes a filter which presents a low impedance to communication signals and a high impedance to mains electricity.

Abstract: A method of determining contact wear in a trip unit of a circuit breaker and a circuit breaker employing such a method are presented. The trip unit includes a microcontroller and associated memories. An algorithm (program) stored in a memory of the trip unit calculates cumulative energy dissipated in the breaker contacts using the current signal detected at the time of separation. Measurement of cumulative energy dissipated in the breaker contacts is proportional to contact wear. Maintenance setpoints are determined based on industry standard endurance tests and alarm threshold and trip thresholds further based on industry standards are provided within the algorithm for notifying local or remote personnel of a necessary maintenance procedure.

Abstract: The electronic trip device comprises a processing unit comprising protection means, and an initialization device of said processing unit. The initialization device comprises means for initialization after an interruption comprising at least one storage register connected to the protection means to store a value of at least one quantity of a protection function and to supply a value of said at least one quantity when initialization of the processing unit is performed. A back-up power supply circuit supplies the storage register, and means for monitoring the back-up power supply circuit delete the register values when a voltage of the back-up power supply circuit drops below a preset threshold.

Abstract: A system for controlling and monitoring operation of an electrical system is described. The system includes a fault protection device, for example, a circuit breaker, that is connected to the electrical system to provide fault isolation. The system also includes a protection system that includes an interface and a logic system connected to the electrical system. The logic system is connected to the interface and controlled by a processor to receive input from the electrical system and input from a user through the interface. The logic system operates the fault protection device when the received input from the electrical system indicates a fault event. Additionally, the logic system indicates information relating to operation of the electrical system through the interface.

Abstract: A light-source lamp unit 100 includes a light-source lamp unit 1 detachably mounted, and CPU 101 constituting drive and control means for the light-source lamp unit. CPU 101 senses the lamp information borne by lamp-information storing block 5 in the light-source lamp unit 1, about a lamp power rating, lamp life and whether a lamp is new or not, and starts counting operation time when the lamp is lit. CPU 101 compares the lamp life sensed and the operation time count, and forces the lamp to extinguish when the life of the light-source lamp expires. Prior to this action, CPU 101 gives a warning display at a time that is earlier than the life expiration of the lamp by a fixed duration of time, to warn that a lamp replacement is needed.

Abstract: A circuit breaker having an external trip indicator, having a circuit breaker housing, a trip mechanism within the housing, sensing a trip condition and being responsive thereto to mechanically break an electrical circuit, an indicator, having a selectively operable retaining mechanism and being biased outward from the circuit breaker housing, and a linkage, sensing a trip condition of the trip mechanism and selectively releasing the selectively operable retaining mechanism to allow the indicator to move outwardly from the housing. The external trip indicator is operated by sensing an overcurrent condition with the trip mechanism, breaking the electric circuit in response to the overcurrent, sensing a mechanical movement of the trip mechanism, and thereby releasing a positional restraint on the mechanical indicator; and allowing the mechanical indicator to protrude from the housing.

Abstract: A device for warning an automotive circuit breakdown comprises a housing and an apparatus located in the housing and provided with a negative conductive piece, a positive conductive piece, a fuse connecting the negative conductive piece and the positive conductive piece, a light-emitting diode fastened with the negative conductive piece, and a coiled spring fastened at one end thereof with the positive conductive piece and at other end thereof with an elastic piece. When the electric current of the automotive circuit becomes too strong, the fuse melts to break the circuit. The electric current is then made available via the coiled spring and the elastic piece to the light-emitting diode which emits light to warn of the automotive circuit breakdown.

Abstract: A multiplexing apparatus multiplexes between processing units and a battery unit of a vehicle which are connected to one another by wire harnesses, by grouping a variety of on-board controlled objects into a plurality of neighboring controlled objects and controlling each of respective processing units. The wire harness has electric conductors of which the outer peripheral portion are covered with a first insulating layer, electric conductivity layer which covers the electric conductors, a second insulating the peripheral portion of the electric layer which covers conductivity layer, means for applying an electric potential to said electric conductivity layer, and means for monitoring the electric potential of said electric conductivity layer.

Abstract: A method of determining contact wear in a trip unit of a circuit breaker is presented. The trip unit includes a microcontroller and associated memories. An algorithm (program) stored in a memory of the trip unit measures temperatures relative to circuit breaker contacts and cumulative energy dissipated in the breaker contacts, and utilizes them in a variety of analysis techniques within the trip unit to determine contact wear. These techniques include, by way of example, differential temperature analysis, measurement of cumulative energy dissipated in the breaker contacts, and calculated contact wear using sampled electrical currents and voltage and Ohm's law.

Abstract: Apparatus for monitoring interruptions in utility power that includes a utility power plug for connection to a utility wall socket to provide a signal indicative of loss of utility power. A counter is responsive to such signal for counting and displaying the number of power interruptions, and a timer is responsive to such signal for measuring and displaying time duration of power interruptions. An operator switch is coupled to the timer for selectively measuring and displaying either duration of the latest power interruption or total duration of all power interruptions. The counter and timer may be reset at the option of an operator.

Abstract: For use in a power distribution system having first and second output power feeds having corresponding first and second circuit protection devices associated therewith, a monitoring system and a method of monitoring a utilization of the power distribution system. In one embodiment, the monitoring system includes: (1) first and second status sensors that sense statuses of the first and second circuit protection devices, respectively and (2) a controller, coupled to the first and second status sensors, that employs the statuses to determine a loading of the first and second output power feeds and calculates a utilization of the power distribution system based on the loading.

Abstract: A circuit configuration for measuring resistance and/or leakage between two nodes, which includes a current source for feeding a test current into one of the two nodes and a circuit element that detects the voltage resulting between the two nodes. The output of a broadband signal generator is connected to a control input of the current source. The outputs of the circuit element and of the signal generator are connected to the inputs of the correlator for determining the correlation between their output signals.

Abstract: A density sensor for monitoring a rate of leakage from the case of electrical switchgear filled with dielectric gas under pressure, the sensor comprising a fixing support mounted from the outside in the thickness of the case and communicating with the dielectric gas. A radiator is placed around the fixing support of the density sensor, thereby enabling a measurement artifact that is due to the exposure of the case and of the sensor to solar radiation to be transformed in such a manner that any risk of untimely crossing of a low density threshold is eliminated.

Abstract: A method of predicting an eminent circuit breaker trip condition using an intelligent electronic device such as a trip unit, a protective relay, a power meter or other IED is presented. The intelligent electronic device includes a microcontroller and associated memories. An algorithm (program) stored in a memory of the intelligent electronic device generates a near-trip event for each trip event calculation if preset thresholds for the measured parameters are breached.

Abstract: A fuse protected power supply circuit for a sensor-operated solenoid controls plumbing fixtures such as automatically-operated faucets, automatically-operated flush valves, hand dryers, soap dispensers and the like. The circuit includes two automatically resettable fuses, one to protect the power supply circuit if the AC-operated solenoid should short and a second to protect the power supply circuit in the event that the sensor which detects the presence of a user of the plumbing device should short. The automatically resettable fuses provide a simple and reliable troubleshooting method in that replacement of either the sensor or the solenoid, depending upon whether one or both are in a shorted condition, allows the circuit to return to normal operation. Such troubleshooting may be undertaken by a maintenance person without the need of sophisticated electronic meters or similar troubleshooting devices.

Abstract: A socket has a hollow base casing, and an upper casing engaging with the hollow base casing. The upper casing has an oblong hole and a pair of slots. The hollow base casing receives a first conductive blade, a second conductive blade, a fixed plate, and a metal bar. A breaker device is disposed between the upper casing and the hollow base casing. A metal bar contacts the first conductive blade. The metal bar will be bent while a current is overloading. Then the metal bar will not contact the first conductive blade. A break display lamp and a resistor are disposed in the upper casing. The break display lamp is connected to the resistor.

Abstract: An apparatus and method for distributing power includes a housing, at least one input terminal, and at least one output terminal. The input and output terminals are each positioned in the housing. The input terminal is operatively connected to the output terminal. At least one circuit breaker is positioned in the housing. The circuit breaker includes an on position and an off position. The circuit breaker is operatively connected to the input terminal and the output terminal. An alarm circuit is operatively connected to the output terminal to prevent an alarm signal when an electronic chassis is not operatively connected to the output terminal and the circuit breaker is in the off position.

Abstract: The present invention relates to an electronic system incorporated into a circuit interrupter device to identify the circuit interrupter device associated with a particular power outlet receptacle.

Abstract: A fuse plug, in particular for terminal blocks in control, regulation and power supply systems, essentially comprising a housing, a fuse-element which is fused upon overshooting of a specific current intensity, contact elements and a display element. Reliable protection against surge voltages is provided. The device ensures that production can be automated with low costs by virtue of the housing (1) being formed from two flat holding halves (2, 3) that can be folded by means of a film hinge 4. The division of the housing is provided in the plane of the plug contacts (5, 6). The fuse-element (7), plug contacts (5, 6) and a display device (19) with a signalling element (15) are arranged in one holding half (2) of the housing (1).

Abstract: An intelligent ground fault circuit interrupter device that incorporates a test and miswiring control circuit in addition to an independent GFCI circuit. Since the test and miswiring circuit is separate and independent of the GFCI circuit portion, it can be used with any circuit interrupting means that can be reset and which incorporates a test circuit. The test and miswiring circuit functions to indicate to a user when the device must be manually tested. The test time events occur upon first installation and on a monthly basis thereafter. The device also indicates that testing is required after occasions of power outage of sufficient time duration and after the device has been tripped by the occurrence of a ground fault. At the times when manual testing of the device is required, a visual and/or audible alarm is triggered and continues until a successful test and reset sequence is completed. The ability to detect when the device is incorrectly wired in an electrical wiring system is also provided.

Abstract: A multiplexing apparatus multiplexes between processing units and a battery unit of a vehicle which are connected to one another by wire harnesses, by grouping a variety of on-board controlled objects into a plurality of neighboring controlled objects and controlling each of respective processing units. The wire harness has electric conductors of which the outer peripheral portion are covered with a first insulating layer, an electric conductivity layer which covers the electric conductors, a second insulating the peripheral portion of the electric layer which covers conductivity layer, a circuit for applying an electric potential to the electric conductivity layer, and a monitor for the electric potential of the electric conductivity layer.

Abstract: The system for determining protection quality of a protective relay and related functions of the protection system include obtaining information concerning the output status of the various protective elements in the relay. The status of various operations in the protective element are also evaluated against specific standards. The operation of supervisory and control elements affecting the action protective elements are also evaluated. Other aspects of the relay, including the availability of the relay and the operation of the voltage and current transformers are also evaluated. In addition, associated aspects such as the status of the communication channels, the station voltage availability and the condition of the trip and close circuits are monitored. All of the above is analyzed in a summary report to provide an indication of protection quality for the relay and associated protection system functions.

Abstract: Provided is a modular precharge circuit capable of rapidly recharging an equipment circuit path prior to insertion of a modular fuse or modular circuit breaker. The precharge circuit includes a switch to begin the operation of precharging, and a charge indicator to indicate appropriate charging has occurred. Charging occurs through use of a resistive network which receives an inrush current due to capacitance in the equipment circuit path. Once an equipment circuit path has been precharged to a desired level, a charge indicator signifies such charging is complete and the precharged unit is removed whereafter an appropriate fuse module and/or circuit breaker module is inserted. The precharge circuit further includes a fusing element and an alarm indicator wherein when the circuit enters a fault state such that the fuse is open, the alarm indicator signifies such a situation.

Abstract: There is disclosed a multi-phase fuse status indicator having a green "good" and a red "bad" indicator LED for each line fuse of the respective phases, the current to the LED's being pulsed to cause them to provide a blinking indication. Power used for the logic circuit for the LED's and the LED's themselves and the related heat dissipation is less than 10 watts and is supplied from the power lines connected through the fuses regardless of the fuses' condition. Only two simple conductor connections are required from the fuse status indicator to each fused line of the multi-phase power system.

Abstract: The method and the apparatus for detecting a deteriorating condition in a bank of standby batteries includes injecting an audio frequency current into one of the battery buses or cables, detecting an audio frequency current signal, matched to the injected audio frequency current signal, that is carried by the battery bus and detecting a voltage drop, at the audio frequency, across the bank of standby batteries. In one embodiment, current transformers are utilized in connection with an oscillator (to inject the AF current signal) and detection circuits (comparators and operational amplifiers) are utilized to generate a representative current signal and a representative voltage signal. The device detects when the standby batteries are operating in a normal, stable condition, that is, when the bank is neither being recharged nor is discharging DC power to the load.

Abstract: In a power distribution system, a reliable, accurate, and energy efficient fault circuit indicator is provided through a microcomputer-based fault current indicator design. First, reliability is improved inherently because the microcomputer, and the software embedded therein, replace the functionality of numerous discrete, less reliable electronic components found in prior designs. Second, the embedded software is capable of placing the fault current indicator in one of a number of energy conservation states, without compromising the fault current indicator's ability to provide information relating to the occurrence of a fault. Finally, greater fault current indication accuracy is achieved by detecting excessive line current, followed by a significant drop in line voltage.

Abstract: The audible alarm system of the present invention incorporates an alarm condition indicator that is designed to detect an alarm condition within the AED. The audible alarm system further incorporates an audible alarm circuit that is connected to the alarm condition indicator and is designed to produce an audible alarm. The audible alarm circuit is initially activated by the alarm condition indicator and then operates independently of the alarm condition after the initial activation.

Abstract: A circuit breaker has line and load terminals and a mechanism which indicates the magnitude of current flowing through the circuit breaker. The mechanism includes a current sensing resistor coupled between the supply and load terminals. An amplifier is coupled to the current sensing resistor and produces a first output signal corresponding to the current magnitude. A first light emitting diode is energized by the first output signal. A first comparator is coupled to the amplifier and produces illumination of a second light emitting diode when the first output signal exceeds a first reference voltage level. A third light emitting diode is illuminated by a second comparator when the first output signal exceeds a second reference voltage level. Thus the number of light emitting diodes that are illuminated indicates the relative level of current conducted by the circuit breaker.

Abstract: An air circuit breaker bell alarm accessory interacts with the circuit breaker operating mechanism to provide local target indication as well as remote signal indication of the separation of the circuit breaker contacts. An indicator switch provides remote signal indication while a lock-out switch interacts with the accessory target to prevent re-closure of the circuit breaker contacts. One of the switches is selected having "normally open" contacts while the other switch is selected having "normally closed" contacts to reduce the amount of mechanical force required to simultaneously operate the indicator and lock-out switches.

Abstract: A circuit breaker includes separable contacts for movement between a closed position and an open position. An operating mechanism moves the separable contacts between the closed and open positions and has a closed state and an open or tripped state which corresponds to the open position. A trip circuit senses electrical current flowing through the separable contacts, employs the sensed current to trip the operating mechanism to the tripped state to move the separable contacts to the open position, and provides plural status signals. A display circuit cooperates with the trip circuit and includes light emitting diodes for outputting the status signals. A battery powers the display circuit which further includes an oscillator circuit for modulating the LEDs to reduce power from the battery to the display circuit.

Abstract: An air circuit breaker bell alarm accessory interacts with the circuit breaker contact position indicator to provide local and remote indication of the occurrence of a circuit interruption. A drive pin extending from the bottom of the accessory interacts with a slot on the contact position indicator lever to reset the bell alarm accessory when the circuit breaker contacts are in the process of being closed.

Abstract: The apparatus detects subsidence current from unfiltered as well as filtered secondary current values in the current transformer. A lack of zero crossings during a predetermined period is a reliable indication of the presence of subsidence current. If subsidence current is detected, then a signal is generated which indicates that the circuit breaker for the power system has opened, providing an accelerated indication thereof relative to an indication produced by an overcurrent element dropping out.

Abstract: For use within an electrical distribution to control current paths through a plurality of associated circuit breakers, a circuit arrangement comprises a plurality of circuit breakers, each having a status related to open contact position and a closed contact position. An informational display is included within the load-center to display the plurality of statuses at a user access side of the display, and a control circuit, coupled to the circuit breakers and the informational display, automatically monitors the contact status of the circuit breakers and drives the informational display so that a display of the statuses is provided.

Abstract: Photoelectric reflective object sensors are mounted in an exteriorly mounted auxiliary switch case to detect a member on a movable contact assembly of the contactor to produce logic level output signals indicative of the operational state of the contactor electromagnet. One or a pair of photoelectric sensors are used in a side mounted auxiliary switch to detect the contactor movable contact assembly in the energized or de-energized position, or en route between the two positions. A single photoelectric sensor is used in a top adder auxiliary switch to detect if the movable contact assembly is or is not in the extended (de-energized) position. The auxiliary switches provided logic level output signals directly usable with microprocessor based controllers.

Abstract: An electrical distribution system having a load center for programmably and remotely controlling a plurality of circuit breakers, an expander unit coupled to the load center and a plurality of external switches for providing signals to the load center representative of the status of the switches. The load center contains a control module that continually receives inputs from the expander unit via an interface module. It also contains a keyboard and display for programming instructions for closing and opening the individual circuit breakers and for displaying the status of the circuit breakers. The interface module, coupled to the control module, causes the circuit breakers to open and close according to programmed instructions received from the control module or another external device. The expander unit contains a plurality of input circuits coupled to external switches.

Abstract: A circuit breaker with trip indicator assembly for indicating the trip status of the circuit breaker. The trip indicator assembly includes a spring powered shaft movable between a cocked position and a trip position in which the spring powered shaft protrudes through the housing of the circuit breaker to indicate the trip status. The shaft is operatively connected to a trip actuating mechanism of the circuit breaker so as to actuate the shaft in response to the trip actuating mechanism actuating an operating mechanism of the circuit breaker. A lost motion coupling is provided to assure that the trip indicator assembly is not actuated until after actuation of the operating mechanism. A bell alarm switch assembly for signalling the trip status of the circuit breaker may be operatively connected to the trip indicator assembly.

Abstract: The circuit breaker comprises a circuit breaker unit onto which there are fixed a communication module, a processing module and a calibration module. The communication module communicates with the processing module only via a connection with galvanic isolation, preferably an optical connection, whereas the calibration module is electrically connected to the processing module. The communication module is, in addition, connected by a mechanical connection to parts of the circuit breaker unit representative of the state of the circuit breaker, and by a bidirectional electrical connection to an external communication bus. An interface connected to the circuit breaker unit can act as support for the calibration module and for an additional module containing information representative of the breaking capacity of the circuit breaker and electrically connected to the processing module.

Abstract: A plurality of monitoring devices are connected to respective pieces of switchyard equipment and associated with a common communications network. A remote host computer is connected to the network to bidirectionally communicate with each monitoring device. The communications network is the existing power line used for delivering power and control signals to the switchyard equipment. Each monitoring device includes testing and/or monitoring circuitry for testing and/or monitoring one or more conditions of the piece of switchyard equipment and generating condition data therefrom, a storage device for storing the generated data, and a transmitter adapted to transmit the data to the remote location via the power line. The remote host computer receives the data transmitted to the remote location and stores the received data therein in a database format. The monitoring device can request previously sent data from the remote host computer.

Abstract: Switching devices can have means for contactless switching position detection. According to the invention, magnetic field sensors arranged at suitable locations inside and/or outside a device housing are provided for switching position detection. In particular, position-dependent magnetic fields are measured for ON/OFF position detection, overcurrent triggering, and contact welding; however, the magnetic field of the current flowing is detected to recognize short-circuit triggering. Differential Hall effect sensors and Reed contacts, respectively, can be used for these purposes. In addition, a sound sensor can be provided for detecting the switching noise, whose signal is evaluated together with the overcurrent triggering signal for short-circuit detection.

Abstract: A device is disclosed for measuring light scatter by particles (3) suspended in a carrier medium with a view to ascertaining the density, size or size distribution of the particles. The device comprises: at least one light source (8) which directs light onto a light-scattering center (2) in the carrier medium with the suspended particles (3); a receiver (4) to pick up a portion of the scattered light from the light-scattering center; and an evaluating device connected downstream of the receiver (4). The invention provides for an elongated detection chamber bounded radially around its central axis by the wall of a housing (1) which also acts as a duct for the through-flowing carrier medium with the suspended particles (3). Each light source (8) is mounted on the wall of the housing (1) and points toward the central axis of the detection chamber.

Abstract: A electronic fuse box is provided with an input device such as a keypad with alphanumeric and data entry keys, a central processing unit made from one or more integrated circuits that is communicatively coupled to said keypad as well as a power switch assembly and a metering assembly. Application is achieved by connecting a power source to the electronic fuse box at the power switch assembly. Also, a plurality of external circuits are electrically connected to the electronic fuse box at the metering assembly.

Abstract: The invention relates to a method of protecting against circuit breaker failure, said circuit breaker having contacts capable of moving between a closed position and an open position, and vice versa, and being fitted with protection apparatus including fault detector apparatus for putting into operation an opening electromagnetic coil that actuates circuit breaker contact drive apparatus, with position-indicator contacts of monitor apparatus being changed over as soon as the circuit breaker contacts start to move. According to the invention, in the event of a fault being detected, a time delay is generated from the indicator contacts changing over, and at the end of said time delay it is verified whether the fault current has become zero, and if not an alarm is generated.

Abstract: Apparatus and method for opening circuit breakers in a circuit are disclosed. The apparatus includes input terminals adapted to be connected to the circuit, a switch and a load. When the apparatus is connected to the circuit and the switch is closed, a current is created in the circuit which overloads the circuit breaker. The apparatus also includes a fuse to protect the device and a LED to indicate when the device is in use. The apparatus can also include multiple loads to be able to create the overload in different circuits.

Abstract: A system for registering a malfunction in telecommunications equipment comprises a protective device including a terminal connector pin and a ground pin connected to ground. The system also includes a housing member for housing the protective device, the housing member including a conductive member attached thereto. A main failsafe switch connects the terminal connector pin to ground through the ground pin in the event of an overvoltage, while an alarm switch connects the conductive member attached to the housing member to ground in the event of the overvoltage. An overvoltage sensitive member contacts both the main failsafe switch and the alarm switch, and retracts both the main failsafe switch and the alarm switch while in a normal operating state of the telecommunications equipment. The overvoltage sensitive member releases both switches in the event of the overvoltage.

Abstract: A monitoring apparatus includes sensors for interconnection with the load output terminal of a corresponding circuit breaker. The sensors sense the closed and open states of the corresponding circuit breakers and produce closure signals at outputs. The sensor outputs are interconnected in series to produce a combined closure signal for all of the circuit breakers. An indicating circuit interconnected with the combined closure signal outputs a signal, such as a relay contact or an audible, visual, or digital signal, to indicate the combined closure status of the circuit breakers.

Abstract: A fuse box is provided with LED's interconnected with all fuses carried by the fuse box for identifying a blown fuse. The LED's are interconnected with the fuses between the positive (current in) input and ground. When a fuse is blown, the fuse results in an open circuit and the flow of electricity is rerouted through the LED to illuminate the LED. Also provided is a liner which fits over an existing fuse box and includes receptacles for fuses with corresponding LEDs associated with each receptacle for indicating a blown fuse. Also provided are individual liners for individual fuses. The individual liner is sized and configured to accept a fuse therein on a first side, and to extend into a fuse box on a second side thereof. The individual liner includes a LED interconnected therewith for indicating a blown fuse. Also provided is a remote indicator having a plurality of indicators positioned away from a fuse box. Additionally provided is a remote fuse box.

Abstract: A fuse protection and fuse blowing circuit includes a fuse register which has an additional fuse with respect to other fuse registers used in the system. The additional fuse has an output which indicates a blown/not blown state of the additional fuse, and that output is fed back to a blow enable input of each of the other fuses in the fuse register and the other fuse registers. When the additional fuse is set to the blown state, none of the other fuses are allowed to be blown, thereby protecting the device against any accidental blowing of fuses.

Abstract: A bell alarm system is provided for a circuit breaker in which the actuation of a flux shift trip device causes an electrical switch to be energized thus providing a bell alarm indication that the circuit breaker has been tripped. The flux trip device impinges against a pivotally rotated lower lever mechanism which has a knee which causes rotation of an upper lever against the influence of a spring attached between the two levers. As the knee moves along a surface of the upper lever mechanism, the relative rotation of the two lever members about their support pins is such as to cause the tension on the spring to increase. Because of this vibration in the circuit breaker itself or minute low level movements of the plunger mechanism will not cause the bell alarm to be actuated.

Abstract: An indicating fuse assembly includes an electrically non-conductive housing; an array of first and second electrically conductive contacts supported by the housing, each pair of first and second contacts being adapted for connecting a replaceable fuse, the contacts being connected in a powered circuit wherein each fuse, when connected between a respective pair of the contacts, is electrically series-connected with a load of the circuit; and a plurality of illuminators electrically connected within the housing for displaying open circuit conditions of corresponding ones of the fuses when the contacts are connected in the powered circuit, electrical current in the illuminators being limited to a minor fraction of a rated current of the corresponding loads. At least some the illuminators can include bipolar pairs of light emitting diodes for activation of the respective illuminators without regard to polarity of the circuit.