Abstract: An electrical device assembly and method to attach an isolated single stud fuse assembly to an electrical device are disclosed. The electrical device assembly consists of multiple studs, one or more of which is replaced with the isolated single stud fuse. A conductive copper landing zone receives an electrically isolated steel stud. When the landing pad assembly is orbital riveted into a plastic housing of the electrical device, the stud is locked into the housing permanently. Electrical devices such as disconnect switches and power distribution modules, both of which include multiple studs, are good candidates for being adapted with the single stud fuse assembly.

Abstract: Provided is an arc protection system in which an arc remover does not operate in a case of a phase-to-phase short circuit fault or a ground/earth fault among arc faults in a distribution panel, the arc protection system including a sensor configured to sense an arc fault of a distribution panel, an arc removing unit configured to ground a fault current, and a control unit connected to the sensor and configured to measure a short circuit current value of the distribution panel, wherein when the arc fault is sensed and the short circuit current value corresponds to a three-phase short circuit current, the control unit drives the arc removing unit, and when the short circuit current value is smaller than the three-phase short circuit current, the control unit does not drive the arc removing unit.

Abstract: An electrical assembly includes a circuit board, a shunt busbar; a connector including a first conductive resilient member and a second conductive resilient member, and a controller. The first conductive resilient member and the second conductive resilient member may be disposed substantially between the circuit board and the shunt busbar. The first conductive resilient member and the second conductive resilient member may electrically connect the controller with the shunt busbar.

Abstract: A fuse unit includes a bus bar and a housing. The bus bar includes a power source-side connection section, an output-side connection section, and a fusible body. A terminal configured to be connected to the output-side connection section includes a bent section and protrusion sections. The housing includes a terminal accommodation section for accommodating the output-side connection. The accommodation space is enclosed with side walls standing upright on both sides of the output-side connection section in an insertion direction of the terminal and on a deep side thereof in the insertion direction of the terminal. The terminal accommodation section includes terminal insertion start-side movement restricting walls and a height-direction and terminal insertion start-side movement restricting wall.

Abstract: A current assignment method and a switch arrangement are disclosed for assigning current, the switch arrangement including two series-connected switches, each including a trigger unit to check whether a preset current condition is satisfied. A signal is sent by the trigger unit of a switch which is postpositionally placed when the current condition is satisfied, the signal at least preventing the immediate triggering of a correspondingly prepositionally placed switch after being received by the corresponding trigger unit. To achieve a technically simple communication connection between switches, in at least one embodiment each trigger unit is formed so as to send but and receive the signal, and each trigger unit includes a measurement unit for measuring an energy flow direction in a subordinate switch and a conversion unit for converting from sending to receiving or from receiving to sending appropriately when the energy flow direction is reversed.

Abstract: An RF signal blocking device includes a capacitor unit and an inductor unit defining an LC resonance circuit. The capacitor unit and inductor unit are set such that a cutoff frequency in the LC resonance circuit after disconnection by fusing of a second inductor including a fuse wire, among first and second inductors of the inductor unit, fluctuates within a prescribed frequency band. The RF signal blocking device reliably blocks an RF signal in a prescribed frequency band after an abnormality of fusing in the second inductor including a fuse wire occurs due to an input of an RF signal having an RF power value greater than or equal to a predetermined level.

Abstract: An integrated power distribution box including an upper level assembly including a printed circuit board comprising at least one electrical component, a lower housing configured to receive at least a portion of the printed circuit board, an intermediate housing configured to be coupled with at least one fuse, a master fuse electrically coupled to the printed circuit board, a lower level assembly including at least one connector corresponding to at least one of the master fuse, the at least one electrical component, and the at least one fuse.

Abstract: A fuse and relay block assembly (10) for an automotive vehicle includes a lower cover (12) and an upper cover (60) mounted in substantially opposed relationship to one another. A relay block (70) is mounted between the lower cover (12) and the upper cover (60) and can receive electrical devices (R, F) mounted along a mounting direction (MD). A relay module assembly (80) is mounted between the lower cover (12) and the upper cover (60) and can receive electrical devices (R, F) mounted along a transverse direction (TD) substantially perpendicular to the mounting direction (MD). Thus, a greater density of electrical devices (R, F) can be mounted within a smaller footprint.

Abstract: An electrical cabinet for housing and interconnecting photovoltaic BOS components can include a plurality of busbars and adjustable fuse mounts to allow for integration of BOS components in a compact space. The cabinet may comprises a base, a busbar mounted on the base, a plurality of standoff devices, and a cover containing the base, the busbar, and the standoff devices. The standoff devices are spaced apart from the busbar. Each standoff device includes a standoff member slideably mounted on the base.

Abstract: A cover apparatus can cover an electrical insulator and an electrical conductor. The cover apparatus includes one or more leg sections for covering a portion of the electrical conductor. The cover apparatus includes a cover section coupled to the one or more leg sections and covering a portion of the electrical insulator. The cover section includes a body portion and an adjustable portion coupled to the body portion at a coupling location. The adjustable portion can be adjusted such that a dimension of the adjustable portion is adjusted according to a dimension of the electrical insulator. An example method of forming a cover apparatus for covering an electrical insulator and an electrical conductor is also provided.

Abstract: A cover apparatus can cover an electrical insulator and an electrical conductor. The cover apparatus includes a leg section that covers a portion of the electrical conductor. A cover section covers a portion of the electrical insulator. The cover section can include a body portion that is coupled to the leg section at a first coupling location. The cover section includes an adjustable portion coupled to the body portion at a second coupling location located on an opposite side of the body portion relative to the first coupling location. The adjustable portion can be adjusted such that a dimension of the adjustable portion is adjusted according to a dimension of the electrical insulator. A method of forming a cover apparatus for covering an electrical insulator and an electrical conductor is also provided.

Abstract: A system includes a rack, computing devices coupled to the rack, a rack PDU, and one or more input power cables. The rack PDU includes an enclosure, two or more power input receptacles on the enclosure, and two or more power output receptacles on the enclosure. The output power receptacles supply power to the computing devices. The input power cables are coupled in one or more of the power input receptacles. The input power cables supply electrical power from an electrical power system to the rack PDU.

Abstract: A cover apparatus is provided for covering an electrical insulator and a conductor. The cover apparatus includes a first cover portion extending along a first axis. The first cover portion includes a first segment covering a first portion of the electrical insulator and a second segment coupled to the first segment and covering a first portion of the conductor. The cover apparatus includes a second cover portion extending along a second axis. The second cover portion includes a third segment movably attached to the first segment and a fourth segment coupled to the third segment and covering a portion of the conductor. An example method of forming a cover apparatus for covering an electrical insulator and a conductor is also provided.

Abstract: An alarm switching matrix, a power distribution unit and a method of operating a power distribution unit are disclosed. In one aspect, an alarm switching matrix for use with multiple types of overcurrent protection devices is provided. In one embodiment, the alarm switching matrix includes: (1) a power circuit coupled to a power input terminal and configured to provide a supply voltage to alarm contact terminals for a circuit breaker and (2) an alarm circuit coupled to an alarm output terminal and a fuse alarm contact terminal that is one of the alarm contact terminals, wherein the alarm circuit is configured to deliver alarm signals to the alarm output terminal from both a circuit breaker connected to the alarm contact terminals and a fuse connected to the fuse alarm contact terminal.

Abstract: An electrically reprogrammable fuse comprising an interconnect disposed in a dielectric material, a sensing wire disposed at a first end of the interconnect, a first programming wire disposed at a second end of the interconnect, and a second programming wire disposed at a second end of the interconnect, wherein the fuse is operative to form a surface void at the interface between the interconnect and the sensing wire when a first directional electron current is applied from the first programming wire through the interconnect to the second programming wire, and wherein, the fuse is further operative to heal the surface void between the interconnect and the sensing wire when a second directional electron current is applied from the second programming wire through the interconnect to the first programming wire.

Abstract: A fusible switching disconnect device includes a switch housing and terminal cover therefore that blocks access to a line side fuse clip and prevents insertion of a rectangular fuse module when switch contacts in the device are closed. An interlock element further presents the fuse from being retracted when the switch contacts are closed.

Abstract: An electrical junction box includes a casing and a relay housed in the casing. The relay is located at an outer end in the casing. The relay includes an electrical component case and a terminal. The terminal is attached through the electrical component case and includes a fixed contact and a movable contact located in the electrical component case.

Abstract: A power distribution box apparatus and method for implementing a priority disconnect scheme and a network communication bridge at a worksite, where the power distribution box distributes temporary power. The power distribution box includes a housing portion and a base portion elevating the housing portion off of the ground or another surface. The power distribution box includes a communication module having a network connecting module operable to connect to an external communication network (e.g., the Internet), and a wireless network module operable to wirelessly communicate with an external device (e.g., a smart phone) to, thereby, connect the external device to the external communication network. The power distribution box may also include a priority disconnect module to selectively disconnect AC output receptacles in response to over-current situations based on a priority level associated with each receptacle.

Abstract: An arc flash relay system is described for use in a power distribution system including an arc flash sensor, a first circuit protection device, and a second circuit protection device. The arc flash relay system includes a first input configured to receive a detection signal from the arc flash sensor, a second input configured to receive a blocking signal from the first circuit protection device, and a controller. The controller is configured to determine that an arc flash has occurred based, at least in part, on the detection signal. The controller activates the second circuit protection device in response to the determination that an arc flash has occurred when the controller is not receiving the blocking signal, and delays activation of the second circuit protection device in response to the determination that an arc flash has occurred when the controller is receiving the blocking signal.

Abstract: A power transfer device adapted for interconnection with the electrical system of a building includes a housing that includes a base having a back wall and an intermediate member that engages the base. A first housing section engages the base and the intermediate member and defines a first interior portion. A second housing section engages the base and the intermediate member and cooperates with the base to define a second interior portion. Fasteners secure the intermediate member, the first housing section and the second housing section together. Power transfer switching components are interconnected with and carried by one of the housing sections. A cover may be pivotably mounted to the housing. During assembly, the power switching components are mounted to one of the housing sections to form a subassembly that is connected to the base as a single unit.

Abstract: An alarm circuit and method of monitoring a circuit protection device are disclosed. The alarm circuit includes a circuit protection device connected in series at an input voltage of a load. The alarm circuit also includes a programmable circuit connected in parallel to the circuit protection device and including an alarm signal. The programmable circuit is programmed to include a plurality of functional states, and at least one functional state corresponds to activation of the alarm signal. The at least one functional state activating the alarm signal corresponds with an interruption condition in the circuit protection device.

Abstract: An energy storage system comprising at least one energy storage module adapted to supply electrical energy to a hybrid vehicle. The energy storage module comprises an enclosure, at least one battery array located within the enclosure, and an energy storage controller module located within the enclosure and electrically connected to the battery array. A high voltage junction box is attached to a first end of the enclosure and having a plurality of high voltage connection terminals connected by a plug-in bussed electrical center configured to reduce the possibility of unintentional grounding or shorting, and decreases the safety risk to a technician during servicing. At least one of the high voltage connection terminals is configured to receive a high voltage conductor connected between the energy storage module and an inverter of the hybrid vehicle.

Abstract: An electrically reprogrammable fuse comprising an interconnect disposed in a dielectric material, a sensing wire disposed at a first end of the interconnect, a first programming wire disposed at a second end of the interconnect, and a second programming wire disposed at a second end of the interconnect, wherein the fuse is operative to form a surface void at the interface between the interconnect and the sensing wire when a first directional electron current is applied from the first programming wire through the interconnect to the second programming wire, and wherein, the fuse is further operative to heal the surface void between the interconnect and the sensing wire when a second directional electron current is applied from the second programming wire through the interconnect to the first programming wire.

Abstract: A fuse and relay block assembly (10) for an automotive vehicle includes a lower cover (12) and an upper cover (60) mounted in substantially opposed relationship to one another. A relay block (70) is mounted between the lower cover (12) and the upper cover (60) and can receive electrical devices (R, F) mounted along a mounting direction (MD). A relay module assembly (80) is mounted between the lower cover (12) and the upper cover (60) and can receive electrical devices (R, F) mounted along a transverse direction (TD) substantially perpendicular to the mounting direction (MD). Thus, a greater density of electrical devices (R, F) can be mounted within a smaller footprint.

Abstract: An electric connection box has a circuit board, a conductive member (a first bus bar, a second bus bar, a first connection fitting, a second connection fitting, or a lead terminal) connected to the circuit board and extending in the direction away from the circuit board, a relay provided at the end of the conductive member which is located on the opposite side of the circuit board, and a case for receiving the circuit board and having an opening provided at a position corresponding to the relay. The relay is exposed at the opening to the outside of the case.

Abstract: Methods, systems, and apparatuses provide power from multiple input power sources to adjacent outputs efficiently and reliably. Aspects of the disclosure provide a power distribution unit (PDU) that includes a number of power outputs including first and second adjacent power outputs. The PDU includes a printed circuit board having a first conducting layer electrically interconnected to a first power input connection and the first power output, a second conducting layer that is at least partially above the first conducting layer and in facing relationship thereto. The second conducting layer is electrically insulated from the first conducting layer and electrically interconnected with a second power input connection and the second power output, the first and second power outputs thereby connected to different power inputs.

Abstract: A device and method of use of a multiple discharge panel for a multiple-discharge, high energy electric device. The device generally uses a panel for a multiple-discharge, high energy electric device that includes a plurality of fuse assemblies constructed in a cascading arrangement in a common panel. Each fuse assembly provides protection from a single high energy discharge pulse and includes a structure defining a cavity. The fuse assembly further contains a resistor made of components that explode when subjected to a large pulse of power to temporarily interrupt and dissipate the large pulse of power. The structure defining the cavity is shaped to deform in response to explosion of the resistor such that a new connection to a remaining one of the plurality of fuse assemblies is established.

Abstract: Methods, systems, and devices for power parameter sensing using power sensing components integrated into a relay are described. A power distribution unit may be provided with switched outputs that may provide or interrupt power provided to the output through a plurality of relays. The plurality of relays may include an integrated power sensor configured to sense one or more power parameters associated with power delivered to a respective power output. A power-related information reporting system may be coupled with the relays and configured to report power-related information derived from the power sensor to a remote system.

Abstract: An apparatus includes a housing portion comprising a back panel, side panels, and a front panel, the back panel and side panels partially defining a cavity having an access orifice, the side panels partially defining an entry area to the access orifice, the front panel arranged to at least partially obscure the entry area to the access orifice and pivot about an axis of rotation, and a first switch disposed in the cavity including a first contact portion secured to the housing portion, and a removable contact portion connected to the front panel.

Abstract: A power transfer device adapted for interconnection with the electrical system of a building includes a housing that includes a base having a back wall and an intermediate member that engages the base. A first housing section engages the base and the intermediate member and defines a first interior portion. A second housing section engages the base and the intermediate member and cooperates with the base to define a second interior portion. Fasteners secure the intermediate member, the first housing section and the second housing section together. Power transfer switching components are interconnected with and carried by one of the housing sections. A cover may be pivotably mounted to the housing.

Abstract: A weatherproof box enclosure adapted to be secured on one of an outside wall and roof location of a multi-tenant building structure supporting roof-mounted solar panel or wind turbine generators including a multiple pole control unit receiving and distributing received alternating current voltages from the generators, which is disengagable by a normally open override switch when supplied voltages fall below a predetermined level, when servicing of the components of the safety box enclosure is to be had, and automatically in the event of an emergency as representative of a closing of the override switch by a ground level control.

Abstract: A fuse box system that combines a series of specially designed fuses in a fuse box that allows an individual to see if one or more particular fuses within the fuse box are broken. The fuse has one of two different configurations, depending on whether the fuse is used in a system that is used in a polarized or non-polarized system. In each scenario, the fuse includes a number of diodes, one of which is a light emitting diode (LED) that will be lit up when the fuse is working and will not be lit up when the fuse is broken and/or not working. Another embodiment utilizes solely LEDs.

Abstract: An apparatus includes a housing portion comprising a back panel, side panels, and a front panel, the back panel and side panels partially defining a cavity having an access orifice, the side panels partially defining an entry area to the access orifice, the front panel arranged to at least partially obscure the entry area to the access orifice and pivot about an axis of rotation, and a first switch disposed in the cavity including a first contact portion secured to the housing portion, and a removable contact portion connected to the front panel.

Abstract: A device and method of use of a multiple discharge panel for a multiple-discharge, high energy electric device. The device generally uses a panel for a multiple-discharge, high energy electric device that includes a plurality of fuse assemblies constructed in a cascading arrangement in a common panel. Each fuse assembly provides protection from a single high energy discharge pulse and includes a structure defining a cavity. The fuse assembly further contains a resistor made of components that explode when subjected to a large pulse of power to temporarily interrupt and dissipate the large pulse of power. The structure defining the cavity is shaped to deform in response to explosion of the resistor such that a new connection to a remaining one of the plurality of fuse assemblies is established.

Abstract: The invention relates to holders for receiving fuses, with a housing having a receiving shaft, the receiving shaft containing contacts which are provided for contacting at least one fuse inserted into the receiving shaft, a cover which is adjustably arranged in the receiving shaft, a fuse holding device which is adjustably guided in the receiving shaft, wherein the cover has a unit being engageable with a guiding mechanism and which holds the cover at a predetermined position within the housing, a coupling device for detachably coupling the cover to the fuse holding device, wherein the unit of the cover is formed by feet which protrude laterally from the cover and are engageable with the guides in the housing, and wherein the guiding mechanism comprises stops and/or stop faces which are provided in the guiding mechanism, and which hold the cover in a top position of the cover.

Abstract: A power source circuit shut off device includes a plug having a terminal metal fitting and a housing to which the terminal metal fitting is attached, and a plug attachment section having a second terminal metal fitting and a second housing to which the second terminal metal fitting is attached. The housing has a second opening section at its side face perpendicular to its bottom face at a second housing side, the second opening section being adapted for attaching the terminal metal fitting to the housing. The terminal metal fitting and the second terminal metal fitting are connected to the second housing. The second housing has a closing wall which closes the second opening section in a state that the housing is positioned at the terminal contact position at which the housing is not yet accommodated in the second housing.

Abstract: An electricity feeding control device is provided with an air hole (31c) which is formed by penetrating a part of a peripheral wall of a body (31) constituting a part of a housing case (3). The housing case (3) is provided in its inside with an inner pressure adjusting sheet (5), formed with a breathable and waterproof member, and arranged so as to cover the air hole (31c) from the inside of the housing case (3). The air hole (31c) comprises a long recess (31c2) formed in an outer surface of the body (31), a communicating hole (31c1) consecutively formed in one end of a longi-tudinal direction of the recess (31c2) and communicated with an inner surface of the body (31), and a shielding plate (33) attached in the outer surface of the body (31) so as to cover a region other than the other end of the longitudinal direction of the recess (31c2), in a region of an opening section (31c3) of the recess (31c2).

Abstract: A modular power distribution system comprises a chassis and a backplane including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the chassis, each module mounted to one of the module connection locations. Each module includes: (i) a circuit protection device; and (ii) a power output connection location. Bus bars connect front power inputs to the backplane.

Abstract: A power transfer device adapted for interconnection with the electrical system of a building includes a cabinet, a set of switches mounted to the cabinet, and wires adapted to connect the switches to an electrical distribution panel associated with a building electrical system. The power transfer device includes a first compartment and a second compartment partitioned from one another by a removable intermediate wall that slidably engages a base that defines a back wall of the cabinet. A first panel closes the first compartment and a second panel is adapted to selectively close the second compartment. The lower compartment provides an interior cavity in which electrical connection between a set of lead wires, connected to the switches, and power input wires can be made.

Abstract: An alarm circuit and method of monitoring a circuit protection device are disclosed. The alarm circuit includes a circuit protection device connected in series at an input voltage of a load. The alarm circuit also includes a programmable circuit connected in parallel to the circuit protection device and including an alarm signal. The programmable circuit is programmed to include a plurality of functional states, and at least one functional state corresponds to activation of the alarm signal. The at least one functional state activating the alarm signal corresponds with an interruption condition in the circuit protection device.

Abstract: An apparatus, such as a metering panel, for electric power distribution. An enclosure having an access opening defining an interior space, at least two electrical components for separate phases of electricity. The two components located within the enclosure and spaced laterally apart, at least one electrically insulating barrier panel, movable between at least two guided positions, a working position within the enclosure and between the components and an access position displaced from the components.

Abstract: An adapter for use between a two-hole blade end fitting of a line post insulator arm and a Y-clevis bolt eliminates the need to replace the entire insulator arm when the end fitting fails or becomes distorted due to wear of the Y-clevis bolt. The adapter includes a body with a two-hole insulator end that connects to the end fitting and a single or double eye conductor end that supports the Y-clevis bolt. The conductor end is configured to align the load axis of the insulator arm with the Y-clevis bolt to transfer the tension load effectively through the adapter. Annular shoulders surround the two holes in the adapter back and the insulator end of the body. The shoulders extend into the bolt holes in the end fitting to center the bolts and form a clamp on the blade end to prevent further damage to the end fitting.

Abstract: A medium voltage circuit-breaker for outdoor applications includes at least one pole part with inner electrical contacts, operated by actuator means via a jackshaft arrangement accommodated in an enclosed main housing having a mounting surface. The pole part is removably attached to the mounting surface and an elastomeric sealing ring is arranged between the end surface of the pole part and a corresponding mounting surface of the main housing. A section of the sealing ring includes a solid porosity material, for air exchange between the inside of the main housing and the environment.

Abstract: Fused load interrupters have up to now used claw terminals or screw connections for connecting to horizontal busbars in a switchgear unit. Fused load interrupters have not been suitable until now for connecting to vertical busbars in switchgear units. At least one embodiment of the invention provides a fused load interrupter with plug contacts, such as are known from load interrupters with fuses, thereby allowing fused load interrupters to replace the more expensive load interrupters with fuses in switchgear units with vertical busbars.

Abstract: The present invention relates to a switch disconnector comprising a housing portion, in which several pairs of blade receiving contacts assigned to each other or the like are arranged, which can be bridged by means of fuses, possibly comprising shock protection covers at least partially covering contact blades, and comprising a lid for receiving said fuses, which is provided in a manner hinged to the housing portion, wherein several receiving means in the form of slots, grooves or the like are formed at the inside of the lid, wherein one bearing cage is provided per fuse, and each bearing cage comprises a cage portion for inserting a fuse, wherein the cage portion is fit to the shape of the fuse to be inserted, and each bearing cage is provided with fasteners, which can be inserted in and snapped into predetermined receiving means for fastening the bearing cage to the lid respectively.

Abstract: A power distribution module for a vehicle includes an insulating housing including a component grid, the component grid defining a plurality of circuit protection footprints, the housing further including at least one connector mount or terminal mating location; a printed circuit board (“PCB”) located within the housing and beneath the component grid, the PCB holding a plurality of fuse mounting terminals and at least one connector mounting terminal, the PCB including a plurality of conducting traces connecting the fuse mounting terminals to the at least one connector mounting terminal; and a cover that threadingly engages the housing, the threading engagement leading to a locking of the cover to the housing that tends to prevent the cover from loosening from the housing when the vehicle is being driven, the locking of the cover able to be overcome by a person so that the cover can be unthreaded readily from the housing.

Abstract: A partitioning device for Medium Voltage cubicles which comprises at least a fixed partition wall and at least a movable partition shutter. The partition shutter is capable to be moved between a first, closed, position and a second, open, position. The partitioning device further comprises an actuating device which is operatively connected to said partition shutter and capable to be operatively interfaced to a Medium Voltage circuit breaker and further capable to be actuated by a movement of said Medium Voltage circuit breaker during an insertion/extraction operation of said circuit breaker.

Abstract: A wireless secondary assembly is disclosed for use in an electrical distribution network. The secondary assembly may include a wireless source electrically connected to a first electric cable and adapted to emit an electromagnetic power signal. A wireless receiver is electrically connected to a secondary device and adapted to receive the electromagnetic power signal and convert the electromagnetic power signal to electricity to power to secondary device.

Abstract: A service disconnect assembly for an electronic module includes a fuse carrier having a holder configured to hold a fuse for the electronic module, where the fuse carrier has an attachment finger extending from the holder. The attachment finger has a peg. The service disconnect assembly also includes a service disconnect cover having a hood forming a channel, with the hood having a window exposing a portion of the channel. The attachment finger is received in the channel to couple the fuse carrier to the service disconnect cover. The service disconnect cover is slidable with respect to the fuse carrier between an initial position and a final position, wherein the hood moves with respect to the attachment finger as the service disconnect cover is moved between the initial and final positions. The peg is aligned with the window in the final position. A handle is rotatably coupled to the service disconnect cover and the handle has a catch aligned with the window.

Abstract: A power supply device for supplying power to a communication device includes a power source, a first fuse, a second fuse, a voltage converter, a photo coupler, and a central processing unit (CPU). The voltage converter is configured for receiving first power signals from the power source via the first fuse and the second fuse, and converting the first power signals to second power signals. The photo coupler connected in parallel to the third resistor, configured for outputting a first electrical signal upon the condition that the first fuse and the second fuse are operational, and outputting a second electrical signal upon the condition that at least one of the first fuse and the second fuse is blown. The CPU is connected to the photo coupler, configured for generating an alarm message upon receiving the second electrical signal from the photo coupler.