Abstract: An apparatus for monitoring a temperature of a structure, comprising: one or more electrically conductive loops adapted to be affixed to the structure, each including first and second elongate connection strips each made of a first metal composition having a first melting point, and a temperature sensitive band connected between the first and second connection strips and made of a second metal composition having a second melting point less than the first melting point. The apparatus further comprises a monitor, connected to respective ends of the first and second connection strips spaced-apart from the temperature sensitive band, configured to detect an open-circuit in the one or more electrically conductive loops caused when the temperature sensitive band separates from either of the connection strips.

Abstract: A system for identifying a selected electrical circuit of interest from a number of electrical circuits, by locating a circuit interrupter connected to interrupt the flow of electrical power from an electrical power supply to the selected circuit of interest. The system includes a remote portion configured to detect when the selected circuit is energized, and in response to generate a wireless signal indicative thereof to a receiver portion located in the vicinity of the circuit interrupter. In response to the wireless signal, the receiver portion is configured to generate an alert indicative to an operator that the flow of electrical power is not interrupted to the selected circuit. By switching the circuit interrupter between the ON and OFF positions, the operator is able to determine from the alert at the receiver portion whether the selected circuit interrupter is connected to control the flow of electrical power to the electrical outlet, load, fixture, or wiring of interest.

Abstract: An electroluminescent (EL) lamp having at least two integral fusible links and a method of manufacturing such a lamp are disclosed. The present invention provides for a fusible link between the front electrode input power contact area and the transparent electrode. In addition, the present invention provides a second fusible link between the back electrode input power contact area and the transparent electrode. The fusible links are designed to become non-conductive (open) if a certain current level is exceeded. The EL lamp fails in a controlled way, without signs of combustion. The EL lamp is therefore protected from self-destruction when subject to an anomaly or manufacturing defect.

Abstract: This invention is intended to reduce the cost by displaying the load information of a plurality of circuits with a single display device and transferring one of the two communication units in the measuring instruments from the measuring instruments to the display device to acquire the load information of a plurality of circuits. The display device and the measuring instruments are separated from each other, and the display device includes a plurality of communications units connectable with a plurality of devices, while each of many measuring instruments includes a single communication unit.

Abstract: Faulted current indicator. Apparatus and method for observing the status of faulted current interrupters for high voltage transmission lines are described. Light emitting diodes powered by a photovoltaic voltage source are used to identify interrupters which have been tripped.

Abstract: The present invention relates to a use indicator apparatus having a power-sensing mechanism and an indicator. The indicator includes a first state and a second state wherein the indicator is maintained in the first state until a required amount of power is applied to the sensing mechanism. Upon reaching the required amount of power, indicator switches from the first state to the second state.

Abstract: Herein provided is a method and apparatus that allows a pre-existing fuse housing to be easily modified and adapted to include a blown fuse indicator light thereon. Whereby when the fuse housing and light in combination are installed within an electrical circuit and if the fuse is no longer functional, the light will automatically illuminate so as to visually notify a user that the fuse needs to be replaced. Also, any suitable light source may be used, such as an LED, a cartridge type having end contacts, a long lasting reusable incandescent lamp, fiber optics, neon, etc.

Abstract: A lighted status indicator for a contact (circuit breaker, switch or fuse) with a distinctive color associated with each position of the circuit breaker. The lighted status indicator is composed of a multi-color light source (usually an LED) together with an electronic circuit that changes the color of that light source, depending upon the status (or position) of the circuit breaker, switch, or fuse.

Abstract: A fault condition monitoring apparatus for use with a fuse cutout includes a housing operable to be supported by the fuse cutout. The housing has first and second contacts operable to make electrical contact with fuse contacts on the fuse cutout when the housing is supported by the fuse cutout. A current sensor is mounted inside the housing and is connected to the first and second contacts. A signaling device is coupled to the current sensor and is operable to cause a signal to be produced when current sensed by the current sensor meets a criterion.

Abstract: A method and apparatus for modifying a power distribution network in a building in order to provide data communication by using a Power Line Carrier (PLC) signal to an approximate electrical central location point of a power distribution system remote from the data entry point of the building. A passive coupler device is attached to a centrally located service panel. The passive coupler receives the Power Line Carrier (PLC) signal from the remote entry point in the building and conditions the signal for entry at the service panel onto each phase of the power distribution network.

Abstract: A fused disconnect switch assembly includes a pull out fuse assembly and a switch housing assembly. The fuse assembly includes a line side conducting portion, a load side conducting portion, and a fuse element therebetween. The switch housing assembly includes a fuse receptacle for receiving the fuse, a first contact assembly coupled to the line side conducting portion of the fuse and a second contact assembly coupled to the load side conducting portion of the fuse when the fuse is inserted into the receptacle. An open fuse indication device is in communication with conducting portions of the fuse, and an alarm terminal output extends from the switch assembly housing and is in communication with the open fuse indication device. The open fuse indication device provides local fuse state indication and the alarm terminal output facilitates remote fuse state indication when coupled to external circuitry.

Abstract: A circuit breaker with a thermal/magnetic trip device incorporates a monitor that senses the temperature of the bimetal and the amplitude of the load current to distinguish between a thermal and a magnetic trip. If the temperature of the bimetal is above a selected value when the circuit breaker trips, a “THERMAL” trip light emitting diode (LED) is energized, while a high load current at the time of a trip lights a “MAG” trip LED. The monitor also energizes an “ARC” LED in response to an arc fault signal from an AFCI at the time of trip, or a “GRD” LED in response to a ground fault trip. If a trip sensor, which monitors load voltage does not detect opening of the circuit breaker contacts when an arc fault or ground fault signal is generated, the corresponding LED is flashed to indicate the failure to trip. The monitor also has a “SURGE” LED to indicate a voltage surge in the protected distribution system as detected by a surge detector built into the circuit breaker.

Abstract: A low cost self-contained power disruption alert device is configured with a light-weight pocket and/or palm sized compact body to generate a local audible alert that is output by a speaker when power to an electrical wall outlet is disrupted.

Abstract: A system is provided for remotely detecting and locating damaged conductors. The system includes at least one slave controller disposed proximate at least one load and electrically connected to the loads via at least one conductor. The slave controller includes at least one solid-state switch capable of controllably altering the input current to the loads, as well as at least one measuring element for measuring at least one parameter associated with the loads and the solid-state switches. The solid-state switch can controllably alter the input current to the loads according to the parameters. The system also includes at least one damaged wire detector electrically connected to the conductors between the slave controller and the loads. The damaged wire detector is capable of detecting and/or locating at least one damaged conductor.

Abstract: A system includes a projector having a consumable component such, as a lamp. The consumable component includes a memory device. An application on the projector has access to the memory device. Additionally, a user interface, updated by the application, is configured to display information from the memory device within the consumable component.

Abstract: An electric power monitoring system includes a source monitor for measuring momentary power output of an electric source supplying electric power to a power distribution system having at least one electric load. The momentary power output is compared with a reference load capability for the electric source to determine the ability of the electric source to support additional load, and load capability data is transmitted based on the load capability. At least one load control receives the transmitted load capability data and controls the supply of power to the at least one corresponding electric load based on the load capability data.

Abstract: A switch unit allows a user to perform an on-and-off switching control of a load which is installed in a certain place without having the user move to the load position and confirm the control status of the load. The switch unit includes a local switching unit having a plurality of buttons each coresponding to each load which is installed in a current place, for directly selecting a load to be switching-controlled, an overall switching unit fabricated in the form of a dial, for selecting a load to be switching-controlled, an overall display unit having a number of LEDs, for displaying the switching control state of each load, an all-off switch which is slightly sunk from the surface of the switch unit, for switching all the loads entirely, and a remote controller signal receiver for receiving a remote controller signal. The switch unit further includes a FND display unit for displaying a load corresponding to the current dial position in the overall switching unit with a numerical symbol.

Abstract: A method of responding to an overload condition includes supplying power on a communication medium in order to provide power to a network element coupled to the communication medium. The method further includes determining if an overload condition exists. If the overload condition exists, the supply of power on the communication medium is stopped for a predetermined period of time. After the predetermined period of time has elapsed, resuming supplying power on the communication medium. If the overload condition still exists after resuming supplying power on the communication medium, signaling a first alarm and/or shutting down a power supply used to supply power on the communication medium.

Abstract: A system for identifying the relative location of devices.

Abstract: Electronic devices that provide notification of and data about power outages. The devices include a voltage input receiver for receiving voltage from a power source; a voltage monitor for monitoring a reference voltage that is received from the power source; a change in voltage detector for detecting a change in the reference voltage with respect to a threshold voltage; a microprocessor; a programmable real-time clock to provide current date and time data; input/output devices for communicating data to the microprocessor; a display to display data transmitted by the microprocessor; and an auxiliary energy power supply that provides power to the device during any power outage. During a power outage, the date and time of the outage are stored and the device is powered by the auxiliary power source. Once power is returned, the date and time of restored power are stored; the duration of the outage is calculated; and the signal indicates that there has been an outage.

Abstract: A fault trip indicator for use with a circuit breaker connected to protect an electrical line comprises a current transformer coupled to the electrical line to produce a current signal which varies as a function of the current level in the electrical line. A threshold detector is coupled to the current transformer to produce a load signal when the threshold detector detects that the current signal exceeds a threshold value. A monitoring circuit is coupled to the protective circuit in the circuit breaker and the threshold detector to provide an indication of the occurrence of the protective circuit opening the circuit breaker while the threshold detector is producing the load signal. A fault trip indicator using passive circuitry, a battery powered threshold detector and binary load signals are also disclosed.

Abstract: A fused disconnect switch assembly includes a pull out fuse assembly and a switch housing assembly. The fuse assembly includes a line side conducting portion, a load side conducting portion, and a fuse element therebetween. The switch housing assembly includes a fuse receptacle for receiving the fuse, a first contact assembly coupled to the line side conducting portion of the fuse and a second contact assembly coupled to the load side conducting portion of the fuse when the fuse is inserted into the receptacle. An open fuse indication device is in communication with conducting portions of the fuse, and an alarm terminal output extends from the switch assembly housing and is in communication with the open fuse indication device. The open fuse indication device provides local fuse state indication and the alarm terminal output facilitates remote fuse state indication when coupled to external circuitry.

Abstract: A switch unit allows a user to perform an on-and-off switching control of a load which is installed in a certain place without having the user move to the load position and confirm the control status of the load. The switch unit includes a local switching unit having a plurality of buttons each coresponding to each load which is installed in a current place, for directly selecting a load to be switching-controlled, an overall switching unit fabricated in the form of a dial, for selecting a load to be switching-controlled, an overall display unit having a number of LEDs, for displaying the switching control state of each load, an all-off switch which is slightly sunk from the surface of the switch unit, for switching all the loads entirely, and a remote controller signal receiver for receiving a remote controller signal. The switch unit further includes a FND display unit for displaying a load correspnding to the current dial position in the overall switching unit with a numerical symbol.

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: A fused disconnect switch assembly includes a pull out fuse assembly and a switch housing assembly. The fuse assembly includes a line side conducting portion, a load side conducting portion, and a fuse element therebetween. The switch housing assembly includes a fuse receptacle for receiving the fuse, a first contact assembly coupled to the line side conducting portion of the fuse and a second contact assembly coupled to the load side conducting portion of the fuse when the fuse is inserted into the receptacle. An open fuse indication device is in communication with conducting portions of the fuse, and an alarm terminal output extends from the switch assembly housing and is in communication with the open fuse indication device. The open fuse indication device provides local fuse state indication and the alarm terminal output facilitates remote fuse state indication when coupled to external circuitry.

Abstract: A method for the early detection of faults in an electric supply system, comprising the steps of continuously checking the existence of RF transients on the electric supply system line, transforming detected transients whose amplitude is above a predetermined level, into a sequence of pulses, analyzing the temporal spacing between pulses to identify those which are due to dimmers, and disregarding them, identifying short-noisy states structures in said sequence, states whose duration is shorter than a period T-ARC, determining short-noisy states where the current amplitudes before and after said states are different, and disregarding these states considered to be caused by normal switching operations, regarding each of the remaining short-noisy states as a faulty event and accumulating such events in a first register, identifying separately long-noisy states in said sequence, states whose duration is longer than a period T-ARC, ascribing a number of arcing events to each long-noisy state proportional to its d

Abstract: A protective switch includes a switch housing, a switching mechanism for closing and opening a movable contact, a tripping mechanism instantaneously pulling a plunger upon detection of an instant current, a tripping control device, an alarm switch, and a trip member. The trip member is divided into an upper trip member away from a bottom of the housing, and a lower trip member close to the bottom of the housing urged by a back spring. The upper trip member includes a plunger operating section opposed to an operating member of the plunger and a switch operating section opposed to an actuator of the alarm switch. The lower trip member includes a locking member operating section opposed to a locking member of a switching mechanism and a tripping section opposed to an operating member of a tripping control device.

Abstract: LED lamp circuitry that emulates an incandescent lamp's behavior upon remote verification of the LED lamp. The invention presents a fuse blow-out circuit and a cold filament detection circuit permitting the use of LED lamps in applications, such as railway signal light applications, where there is a need for remote monitoring of the lamps, while keeping the advantageous features of lower power consumption and longer life. The invention also provides a control circuit for enabling/disabling the power supply to LED lamps in relation to the level of the line voltage. The advantage of this embodiment is to avoid unwanted functioning of the LED lamp caused by interference from surrounding electrical cables.

Abstract: A high-voltage-proximity warning system has a local panel (1) for being positioned in or about a cab (2) of heavy equipment or other vehicle (5), a remote panel (3) in predetermined electrical communication with the local panel and one or more proximity antennas (4) for being positioned selectively on the vehicle in predetermined electrical communication with the local panel. The local panel is adapted to be push-button operable conveniently by an operator with gloved hands in a position where it is readily visible and easily connectable electrically to the remote panel and to the one or more proximity antennas. The remote panel is adapted to be positioned on or off of the vehicle where it can be protected for supportive operation and accessed for plural electrical connection to electrical devices that can include an electrical-source terminal (11), to speakers, and to warning and alarm communication devices (50).

Abstract: The present invention provides an improved fused disconnect. More specifically, the present invention provides a fusible disconnect that includes a single line side terminal, two independent load side terminals, two independent removable fuse carriers and two independent blown fuse indicators. The common line side terminal provides power to both of the removable fuse carriers. The present invention therefore enables a single, standard sized disconnect to isolate and provide overload protection for two electrical load devices, thus reducing the required number of fused disconnects by one half. The present invention also reduces the required number of line side connections by one half. To this end, in an embodiment of the present invention, a multiple pole fused disconnect includes a housing, a line terminal secured to the housing and a plurality of load terminals secured to the housing.

Abstract: LED lamp circuitry that emulates an incandescent lamp's behavior upon remote verification of the LED lamp. The invention presents a fuse blow-out circuit and a cold filament detection circuit permitting the use of LED lamps in applications, such as railway signal light applications, where there is a need for remote monitoring of the lamps, while keeping the advantageous features of lower power consumption and longer life. The invention also provides a control circuit for enabling/disabling the power supply to LED lamps in relation to the level of the line voltage. The advantage of this embodiment is to avoid unwanted functioning of the LED lamp caused by interference from surrounding electrical cables.

Abstract: LED lamp circuitry that emulates an incandescent lamp's behaviour upon remote verification of the LED lamp. The invention presents a fuse blow-out circuit and a cold filament detection circuit permitting the use of LED lamps in applications, such as railway signal light applications, where there is a need for remote monitoring of the lamps, while keeping the advantageous features of lower power consumption and longer life. The invention also provides a control circuit for enabling/disabling the power supply to LED lamps in relation to the level of the line voltage. The advantage of this embodiment is to avoid unwanted functioning of the LED lamp caused by interference from surrounding electrical cables.

Abstract: LED lamp circuitry that emulates an incandescent lamp's behaviour upon remote verification of the LED lamp. The invention presents a fuse blow-out circuit and a cold filament detection circuit permitting the use of LED lamps in applications, such as railway signal light applications, where there is a need for remote monitoring of the lamps, while keeping the advantageous features of lower power consumption and longer life. The invention also provides a control circuit for enabling/disabling the power supply to LED lamps in relation to the level of the line voltage. The advantage of this embodiment is to avoid unwanted functioning of the LED lamp caused by interference from surrounding electrical cables.

Abstract: A fuse state indicator includes a fuse casing having a transparent lens, a combustible substance disposed adjacent the lens, and a base layer disposed adjacent the combustible substance and having a contrasting color relative to the combustible substance. A secondary fuse indicating circuit is electrically connected to a main fuse circuit in parallel with a main fuse link, and includes a secondary fuse wire link which is disposed adjacent the combustible substance. Heat created upon vaporization of the secondary fuse link ignites the combustible substance and reveals the base layer through the lens after combustion, thereby indicating a state of the fuse as operable or inoperable by the color visible through the lens. Combustion may be assisted with an energetic chemical compound applied to secondary fuse wire link and combustible substance.

Abstract: An electrical component is proposed that has at least one voltage divider that can be read out using an evaluation unit to identify the electrical component by means of a voltage measurement. An evaluation unit is first connected to the electrical component, and a voltage measurement is carried out and converted by way of an analog-digital converter into a digital code with which the electrical component can be identified. This identification can be output via a data output to an electrical device.

Abstract: Compatibility with a current transformer having several kinds of rated current ratios is achieved by finding out a formula of relationship between errors arising in a transformer input circuit and detectable ranges set as setting values of the input circuits which can be optimally set. In connection with that, by dispensing with a gain control section, the number of components, the mounting area and the cost can be reduced. Arithmetic expressions representing the relationship among errors arising in the transformer input circuit, the instrumentation ranges of the input circuits, and detectable errors have been derived. Further by optimally setting the detectable ranges of the input circuits, which are the parameters of the arithmetic expressions, the configuration compatible with a current transformer having several kinds of rated current ratios is achieved.

Abstract: The invention relates to a fuse holder for a fuse-link in which a fuse status indicator having a printed circuit board and a glow lamp is fitted. The necessary connecting lines are made of conductive plastic from the top and base contacts of the fuse-link to the printed circuit board of the status indicator. The conductive plastic is injected in channels which are provided therefor and are situated in the housing of the fuse holder.

Abstract: The system for remote and non-visual detection of illumination device operation which is operational to identify the operational state of individual illumination devices. This is accomplished by placing the unit under test in a steady state operating condition during the burn-in and/or environmental stress testing process. The illumination devices are individually selected and operated during the test and the operational state of the selected illumination device determined. The determination of the operational state of the illumination device is effected by measuring the incremental change in power drawn by the unit under test resulting from the activation of the selected illumination device. An anomaly in the measured change in power consumption is indicative of a failure mode for the selected illumination device.

Abstract: An alarm filter circuit used in telecommunication systems for interconnecting between incoming telephone lines and alarm unit located at a subscriber's premises so as to block DSL data signals to and from the alarm unit for preventing interference is provided. In one preferred embodiment, the alarm filter circuit includes a second-order low-pass filter section for blocking the DSL data signals to and from the alarm unit, a first-order high-pass filter section for bypassing the DSL data signals on the incoming telephone lines to the house wiring, and a first-order low-pass filter section for blocking high-frequency signals between the house wiring and the alarm unit. In a second embodiment, a fourth-order elliptical low-pass filter section replaces the second-order low-pass filter section. In a third embodiment, a third-order high-pass filter section replaces also the first-order high-pass filter section.

Abstract: The present invention provides an improved fused disconnect. More specifically, the present invention provides a fusible disconnect that includes a single line side terminal, two independent load side terminals, two independent removable fuse carriers and two independent blown fuse indicators. The common line side terminal provides power to both of the removable fuse carriers. The present invention therefore enables a single, standard sized disconnect to isolate and provide overload protection for two electrical load devices, thus reducing the required number of fused disconnects by one half. The present invention also reduces the required number of line side connections by one half. To this end, in an embodiment of the present invention, a multiple pole fused disconnect includes a housing, a line terminal secured to the housing and a plurality of load terminals secured to the housing.

Abstract: The present invention comprises a remote marine monitoring and control system that compiles security information and statistics for on-board equipment on unattended boats, uses a wireless transmitter to send this data to a user over a communications network and allows a user to remotely operate the user's boat in response. Boat operational data can be provided to a user on a variety of personal communication devices and/or through a monitoring web site. These devices can also be used by the user to send a user command to remotely control the operation of the boat. The remote marine monitoring system identifies normal operating conditions for on-board equipment and compares these conditions to current operating activity in order to detect unusual activity. Security information can also be compiled and reported relating to intrusion sensors, keyless entry and the boat's physical location.

Abstract: A protective relay, system, and relay operation method which allows logic functions to be distributed amongst multiple protective relays associated with a power distribution system. The protective relays include communications ports for exchanging messages over a peer-to-peer communications network, and include programmable logic. Each protective relay receives logic operands contained in the messages from remote protective relays, executes logic equations using the received operands, provides protective control if needed, and outputs operands to other protective relays.

Abstract: A projector is provided which is able to facilitate a reduction in size. The projector includes of a lamp information carrier circuit board and a lamp information detection circuit board, and a fuse for determining use and nonuse of a light source lamp. The lamp information carrier circuit board is stacked so as not to overlap the lamp information detection circuit board. For this reason, the lamp information carrier circuit board and the lamp information detection circuit board are stacked close to each other, and the space between the lamp information carrier circuit board and the lamp information detection circuit board can be narrowed.

Abstract: A power distribution panel having circuit elements such as KTK and GMT fuses removably mounted to a unit housing by means of module members, thereby allowing for ease of customization of the circuit elements of the power distribution panel.

Abstract: A fuse device includes two prongs secured in a casing, and a fuse member secured between the prongs. An indicating device is electrically coupled to the prongs or to the fuse member for generating a warning or an indicating signal when the fuse member is broken. The indicating device includes a pair of conductor blades electrically coupled to the prongs, and an indicating member, such as a light device or a buzzer, secured between the conductor blades for generating an indicating light or a warning sound when the fuse member is broken.

Abstract: A method of detecting systemic fault conditions in an intelligent electronic device is presented. The intelligent electronic device includes a microcontroller and associated memories. An algorithm (program) stored in a memory of the intelligent electronic device detects systemic fault conditions, i.e., root causes, as indicated by repeated, similar fault events.

Abstract: A method and system for monitoring relay status using a lighting control panel is disclosed. The lighting control panel is used, for example, to control lighting throughout a building. The method includes the steps of commanding at least one relay to an on or off position from the lighting control panel, monitoring the status of the at least one relay from the lighting control panel, and setting the state of an indicator on the lighting control panel to show relay OFF, relay ON, or relay failed based on a monitored relay status.

Abstract: A fused disconnect switch assembly includes a pull out fuse assembly and a switch housing assembly. The fuse assembly includes a line side conducting portion, a load side conducting portion, and a fuse element therebetween. The switch housing assembly includes a fuse receptacle for receiving the fuse, a first contact assembly coupled to the line side conducting portion of the fuse and a second contact assembly coupled to the load side conducting portion of the fuse when the fuse is inserted into the receptacle. An open fuse indication device is in communication with conducting portions of the fuse, and an alarm terminal output extends from the switch assembly housing and is in communication with the open fuse indication device. The open fuse indication device provides local fuse state indication and the alarm terminal output facilitates remote fuse state indication when coupled to external circuitry.

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: A lighted status indicator for a contact (circuit breaker, switch or fuse) with a distinctive color associated with each position of the circuit breaker. The lighted status indicator is composed of a multi-color light source (usually an LED) together with an electronic circuit that changes the color of that light source, depending upon the status (or position) of the circuit breaker, switch, or fuse.