Abstract: An electrical connector for use in electrically conductive aqueous mixtures, solution or suspensions such as seawater, sewage, electrolytes and so forth has one or more contact pins 3 each having a contact area 4. The contact areas 4 are electrically isolated from the electrically conductive environment by way of a dielectric seal carrier 6 which may be moved away from the contact areas 4 as the socket and the plug of the connector are brought into engagement.

Abstract: A safety receptacle includes an insulating housing including a socket assembly having a first contact means and a second contact means therein adapted to receive the prongs of an electric plug, and first and second terminal means wherein the second terminal means is electrically active. A means for completing an electrical circuit through the prongs of the electric plug only when the prongs are in contact with the contact means includes means for electrically connecting the second contact means to the second terminal means only when one prong of the electric plug is received in the first contact means.

Abstract: A modular element for an electrical power distribution ducting has an elongated box section structure. Inside the box section structure conducting electrical power distribution bars are arranged. Lateral access can be gained to the bars through distribution openings in the box section structure. At least some of the openings are protected by a closing-off protective device in the absence of a tapping. The box section structure is composed of two beam members each having two longitudinal grooves into which the respective longitudinal edges of two pre-shaped strips having a U-shaped cross section engage elastically. The edges are fixedly retained inside the longitudinal grooves of the beam members. One of the beam members optionally carries bus bars for low current power distribution.

Abstract: A bezel connector for an electronic device in a vehicle, such as a radio, having a removable bezel. The bezel connector has a support member that is removably attached to the radio housing, and along with the other components of the connector form a removable module. The support member supports a PC board, which has connector pins protruding therefrom in spaced relationship. The connector pins are rigid and protrude from the PC board in a cantilever fashion. Also movably supported by the support member is a cover member having an electrically conducting portion. The cover member includes holes aligned with the connector pins to thereby shield and support the connector pins. Grounding springs bias the cover member in a position which selectively shields the connector pins and also provides an electrical connection between the cover member and the radio housing to discharge any static electricity charge that may be imparted to the cover member.

Abstract: An electric connector provided with a protective cover for protecting terminals fixed in a male connector housing. Locking components formed on the protective cover and the housing are interlocked with each other so as to make the protective cover stable except when the male housing is fitted in a corresponding part. By inserting the male connector housing into the corresponding part, the locking components are automatically released from the interlock, the protective cover is slid by the wall of the corresponding part, and the terminals are connected with circuit patterns of a printed wiring board mounted on the wall of the corresponding part. The electric connector permits the protective cover to securely protect the terminals against a collision with other male housings when they are conveyed, for example.

Abstract: A terminal member mounted in a connector is made repairable without removing a protection plate mounted in the connector while facilitating the movement of the protection plate. The protection plate is formed with jig holes close to terminal holes for allowing the terminal contact portions to penetrate therethrough. By utilizing a lever mounted to a lever type connector, the protection plate can be moved as interlocked with pivotal rotation of the lever.

Abstract: A connector with a cover for connecting an electric wire to a printed circuit board or a like element wherein a half inserted condition of a terminal accommodated in a housing can be detected. A plurality of terminal accommodating chambers each having a flexible arresting piece formed on an inner wall thereof are formed in a housing body and each has a terminal accommodated therein. The terminal is connected at an end thereof to an electric wire and has an engaging hole formed at a rear face of the end portion thereof. The terminal further has a contact piece folded back over itself from the other end to an intermediate portion thereof and has a protrusion formed at an intermediate portion thereof by bending a pair of side plates thereof inwardly toward each other. The contact pieces and protrusions are exposed outside through slots formed in a top plate of the housing body.

Abstract: In a terminal protection type connector in which a flexible locking arm for locking a female connector housing is provided on a male connector housing, and the elastic contacts of terminals accommodated in the male connector housing are exposed through openings formed in the latter, a terminal protecting member is slidably mounted on the male connector housing in such a manner that said terminal protecting member covers the openings and engages with the flexible locking arm.

Abstract: A test connector for connection to two test inputs of a trip device. The test connector includes a fixed component made of electrically insulating material, wherein the fixed component includes a sleeve defining an inner space. A movable component is provided within the inner space and is axially movable therein. The movable component includes a protruding portion which extends from the fixed component. A spring is provided between the movable component and the fixed component to provide a biasing force to urge the movable component in an outward axial direction. Two testing needles are housed within two longitudinal passages within the movable component. Upon insertion of the test connector into a recessed portion of a face of an electronic trip device, the movable component is urged rearwardly to expose the two testing needles which pass through orifices int he recessed portion to contact the two test inputs of the trip device.

Abstract: For the purposes of connecting and joining conductive traces on printed circuit boards, the stripped ends of a flexible multi-conductor flat cable are inserted into metallized openings in the printed circuit boards. The cables are cut to length and their ends are stripped of insulation and supported in an injection molded bar member. Those ends are desirably not to be bent in storage and transportation. In order to protect them, a U-shaped device is pushed onto the bar member over the cable ends. The bottom plate portion of the device has holes of a conical configuration. In a transportation position the ends are disposed within the walls of those holes and are held therein. The device latches in the transportation position. For the ends to be inserted into the holes in the printed circuit board the device is pushed further onto the cable ends in an operative position. As such, the ends pass in a guided fashion through the holes in the bottom plate portion and into the holes in the printed circuit board.

Abstract: A memory card ejector has an eject knob to be externally operated and a lock release button. As a memory card is loaded in a card receiving chamber, a lock lever moves to a locking position so that a claw of the lock lever engages with a recess of the memory card to lock the card at a load completion position. In association with the lock lever, a card detecting switch turns off the supply of power to circuit components of an electronic apparatus. When the lock release button is depressed, the lock lever rotates in the counter-clockwise direction to move to a lock release position whereat the card detecting switch is turned off to stop powering the electronic apparatus. As the eject knob is slid, an associated lever together with an eject lever moves so that the end of the eject lever pushes a slide plate toward a card inlet port with a relatively strong force. A hook of the slide plate pushes the front end of the memory card to discmount it from a connector.

Abstract: A connector comprises, a first connector housing having first metal terminals, a second connector housing having second metal terminals engaged with the first metal terminals provided with the first connector housing, and a locking device for engaging the first connector housing with the second connector housing. The lock device includes a spring receiving device, slidably disposed in the first connector housing, for receiving a repulsive force acting between the first and second connector housings through the spring receiving device, and a spring device, for applying the repulsive force to the first and second connector housings through the spring receiving member, disposed between the first connector housing and the spring receiving device.

Abstract: An electrical male connector assembly incorporates a floating shield that is resiliently held in a position on the connector body wherein the male contact pins are hidden or shielded from contact by the shield in its outermost position. When the connector member is mated with a corresponding female connector, the opposed face of the female connector impinges on the shield and cause it to be slid along the contact pins to a retracted position. Means are provided for biasing the shield toward its outermost position. The shield face is metalized to provide an exposed ground plane in electrically conductive contact with a metal portion of the connector member shell to drain off any electrical static discharges that might otherwise come into contact with the exposed contact pins.

Abstract: An electric test connector is arranged for temporary for connection with another connector, for checking the electric continuity of units connected to the other connector. It comprises: a pluggable casing and a lock carried by the casing and arranged for retaining the other connector. An electrically insulating plate is movable in the casing along the plugging direction and arranged for abutting connection with the front face of the other connector. The plate is resiliently biased. Electrical contact pins carried by said plate are resiliently biased forwardly towards a position where they have a predetermined amount of projection with respect to the plate. The pins are distributed according to a predetermined pattern corresponding to that of electrical contacts in the other connector.

Abstract: An electronic equipment cabinet is shown having an integrated cover panel which provides a plurality of connector receptacle positions to which outside equipment may be connected. Connector contacts are snap locked into the receptacle positions. The connector receptacle contacts are automatically bridged when the mating connector plug is removed to short circuit the connector contacts. L-shaped bridging contacts maintain positional stability while L-shaped connector contacts permit direct insertion of the contacts into a printed circuit board within the equipment cabinet. Two unitary ground strips are fashioned to provide shielding shrouds around each of the plurality oconnector receptacles while attaching as single units to the cover panel and closing ground contact with the cabinet housing. This cabinet arrangement finds one use as a trunk access unit to interconnect a plurality of data stations into a local area ring network.

Abstract: Disclosed is a means for aligning contact leads in electrical connectors. An alignment strip includes a pair of slidably mounted sheets, each defining an array of openings having wide and narrow portions. The sheets are initially positioned so that the wide portions of corresponding openings in the two arrays overlap to permit easy insertion of the leads. The sheets are then shifted to align the narrower portions of the corresponding openings so that the leads are held in place in their proper location.

Abstract: A connector for an electric part has a plurality of contacts for connecting with an electric part. Leg portions of the contacts are arranged in such a manner as to project from a connector board. The connector also has a locator provided with a plurality of positioning holes formed in a surface of the connector board from which the leg portions of the contacts project. The positioning holes are adapted to permit the leg portions to extend individually through the connector board. The locator can be moved between a first position close to the connector board and a second position spaced apart from the connector board. The connector further includes temporary fixing means for temporarily fixing the locator in the second position spaced apart from the connector board.

Abstract: An electrical connector has a protective cover which moves slidably between a first position, which exposes a plurality of metal terminals to corresponding portions of a printed circuit board, and a second position, which covers the terminals. Unless the connector is inserted properly, the protective cover will cover the terminals, preventing contact with the printed circuit board. A detecting piece on a mating connector housing the printed circuit contacts moves the protective cover when the connector is inserted into the mating connector.

Abstract: An IC card having a shutter, in which the right and left sides of the shutter are bent to form L-shaped flanges enclosing the sides of an electrode terminal board, the shutter sliding over the electrode terminal board.

Abstract: A connector with a slide cover includes a connector housing. An upper side of a connector housing is completely removed to open terminal-receiving chambers of the connector housing. A cover is slidably mounted on the connector housing so as to cover electrical contact portions of terminals received respectively in the terminal-receiving chambers.

Abstract: A revolving safety socket of the present invention has a uniquely-designed stand, which serves as a switching device. It consists mainly of a circular hole in the case cover and a circular recess in the case base. Located between the circular hole and the circular recess is a revolving stand having receptacles therein. When the socket is not in use, the conductive member of the revolving stand is not in contact with the copper clip which is connected to the power supply. Only when a plug is inserted into the revolving stand, which is then rotated for a 90-degree angle, would the conductive member become engaged with the copper clip to permit the power supply to be on. Additionally, the socket has the reversed L-shaped fasteners to hold the protruded block of the plug firmly in place, ensuring that the plug can not be accidentally pulled out of the socket.

Abstract: An integrated circuit card including one or more integrated circuit elements interacts with a lever extending into a card-receiving receptacle in electronic apparatus for verifying correct insertion and opening a sliding shutter in the card. The integrated circuit elements are enclosed in a case having an opening for exposing a contact pattern that connects the integrated circuit elements to the electronic apparatus. The shutter is biased toward a closed position in which a forward surface covers the contact area. An inclined chamfer on a forward section of the case interacts with the lever to limit insertion to only one orientation of the case. By providing a tab on the rear of the shutter that extends from the case on the same side as the chamfer, the lever initially verifies correct insertion and subsequently engages the tab to drive the shutter to an open position exposing the contact pattern to the electronic apparatus.

Abstract: Disclosed is a data-processing apparatus comprising a data-processing unit, a connector unit, a pin-protecting member, and lock members. The lock members hold the pin-protecting member in a first position where the pin-protecting member opposes the pins and prevents anything other than the card-shaped recording medium from abutting on the pins and protects the pins from dust. When a card-shaped recording medium is inserted into the apparatus, the lock members release the pin-protecting member from the first position, whereby the pin-protecting member is moved to a second position. In the second position, the pin-protecting member allows an electrical connection between the pins and the connector of the recording medium. When the recording medium is pulled from the apparatus, the pin-protecting member is moved from the second position back to the first position.

Abstract: A safety socket includes a cover plate having an opening, a spring-biased stepped plate, and a base plate having a first recessed portion for fixedly receiving the cover plate and a second recessed portion within which the stepped plate is slidable. Both the stepped plate and the base plate include a respective pair of hot slots. The stepped plate includes a raised plate which is designed to cooperate with the opening of the cover plate so that the raised plate is displaceable within the opening of the cover plate from a safety position, where the pair of hot slots on the stepped plate blocks the pair of hot slots on the base plate, to a work position, where the two pairs of hot slots are aligned for receiving a plug.

Abstract: A power supply structure is disclosed in which a base member has first and second sets of plug pin receiving openings with electrically conductive sockets behind the openings. Each first set is grouped with a second set, and the sets are provided with power from separate sources e.g. clean and contaminated power. Socket modules each of which includes electrically conductive pins can be plugged into the openings. Each socket module has plug pin receiving openings for receiving plugs on power leads. In one form each socket module is unplugged from the base member, turned through 180 degrees and plugged into the base member again to change from one type of power to another. In a further form the base member includes switches which provide power selectively to the socket behind the first and second sets of openings.

Abstract: The electrical connecting apparatus tests for electrical faults in an electrical and/or electronic device having a circuit board, wire support or the like equipped with a plurality of blade-terminal strips and/or sleeve-terminal strips has at least one supporting device which has test contacts for testing the blades or sleeves of the blade-terminal strips and/or sleeve-terminal strips of the device being tested and restoring springs which may include a plurality of coil springs. The electrical contact between the socket and/or terminal strip of the device being tested and the test contacts is made by at least partially overcoming the spring forces of the restoring springs.

Abstract: A construction for removing electrical charge generated in a data input device when the data input device is connected to a data storage device. Contacting members connected to a ground are provided on the connector of the electronic apparatus and contact conductive members of the input device to remove electrical charges prior to connecting the input terminals of the input device to the connector terminals of the electronic apparatus.

Abstract: A memory card having: a card-like package; a semiconductor module disposed within the package; a plurality of electrode terminals mounted on the package for external electrical connection of the semiconductor module in the package to an external circuit; a metallic shutter disposed on the package and movable between an open position in which the electrode terminals are exposed for the electrical connection and a closed position in which the electrode terminals are covered; and an insulating layer formed on a surface of the shutter which faces the electrodes.

Abstract: New cover assemblies for electrical fixtures in buildings allow conventional outlets and (toggle) light switches to be cheaply converted into a variety of different color designs and/or colors without changing the electrical infrastructure of the fixture. The cover assemblies comprise a cover plate with an appropriate number of orifices, each orifice being covered by a slider so that the whole cover assembly shields the conventional parts of the fixtures normally visible in building interiors.

Abstract: In an electrical connector which has to operate in fluid-tight manner in a liquid medium, in which one of the connector elements comprises contacts distributed circumferentially around an axial bore provided with a movable obturator and the other connector element comprises a cylindrical body adapted to penetrate into the bore by pushing back the obturator and provided with contacts distributed over its periphery and borne by insulating bodies of PTFE, the contacts are borne by insulating bodies of elastically deformable elastomer with the possibility of limited radial movement (springs) of the contacts with respect to the insulating bodies.

Abstract: A connector for a thin electronic appliance, for example, an IC card reader for electrically connecting the thin electronic appliance with its receiving member, for example, an IC card reader/writer, which comprises a detector switch key body of insulation rubber having a connector base rigidly secured to the receiving member, a plurality of contact electrodes of electrically conductive rubber securely held by the connector base, and a push button portion having a plurality of openings through which the contact electrodes extend. The key body is further provided with a plurality of resilient leg portions extending from the connector base and a key top portion carrying the push button portion and supported by the leg portions. The connector is combined with a detector switch having a plurality of stationary contacts rigidly secured to the receiving member and a movable contact rigidly secured to the lower surface of the key top portion.

Abstract: A memory card with a connector having a male contact including a relatively large numbers of connecting pins. The card comprises a card-shaped housing in which a female contact is disposed to be accessible by the male contact from the outside of the housing. The housing also contains therein internal conductors between internal components and the female contact. The female contact comprises an elastomer connector having an electrically insulating elastomer and a large number of electrically conductive fine fibers, each having a first and a second end. The conductive fibers extend through and are supported by the insulating elastomer for establishing a large number of independent electrically conductive paths therethrough. The dimensions and the pitch of the conductive fibers is so fine that the respective conductors and the corresponding external male pin are electrically connected through at least one of the conductive fibers when the male and female contact are connected.

Abstract: A snap-together enclosure comprises a cover, a shutter mechanism, and a base plate. The enclosure is designed to encase a jack receptacle body which is heat staked to a terminal block. The shutter mechanism is snapped into a hole in the cover and is held in place by means of tabs on the shutter and interfering ridges on the cover. The terminal block is snapped into the base plate by means of tabs on the base plate and interfering ridges on the terminal block. Finally, the cover is snapped onto the base plate, again by use of tabs and interfering ridges on the cover and base plate respectively. When the cover and shutter assembly is attached to the base plate, the jack receptacle body, enclosed therein, pushes against back walls of the tabs on the shutter to prevent the shutter from disengaging with the ridges on the cover.

Abstract: An improved light socket for use with light bulbs of conventional design and threaded base, has a frame and a cup adapted to accept the light bulb base mounted for longitudinal motion within the frame between a first extended position and a second retracted position. Electrical contacts are provided for establishing electrical continuity with the bulb, the contacts being engaged with the bulb when the cup is in the second, retracted position and disengaged from the bulb when the cup is in the first, extended position. An engagement finger engages the bulb thread when the cup is in the retracted position to retain the bulb in the cup, and releases the bulb when the cup returns to the extended position.

Abstract: An IC card having a package in which a semiconductor device is accommodated, a plurality of electrode terminals disposed on a surface of the package near the front end thereof in the direction in which the IC card is inserted into a connector in an external device, a shutter supported on the surface of a front portion of the package for exposing and covering the electrode terminals, the shutter having a width smaller than that of the package as measured in the direction perpendicular to the direction of insertion into the connector, a pair of guide projections formed on the shutter at both-sides thereof to extend into the package, the guide projections functioning to open the shutter by abutting against a pair of shutter receiving pins disposed in the insertion hole of the connector when the package is inserted into the connector, and a pair of guide grooves adapted to guide the guide projections, the guide grooves being formed in both sides of the front portion of the surface of the package to be within the

Abstract: The disclosure herein describes a safety guard which comprises a cover with openings adapted to be mounted over an electrical wall outlet and closure elements which are slideably mounted to the cover to expose or to cover the openings in registry with sockets of the wall outlet. The cover and the closure elements are structured so as to require two movements to displace the closure elements from a socket-covering position to a socket-exposing position. Also, a spring element connected between the cover and each closure element serves to bias the latter to the socket-covering position as the closure element is moved to expose the opening.

Abstract: An IC card connecting mechanism connects an IC card having a terminal array with a connector for connecting the IC card to external equipment. The IC card connecting mechanism includes a frame of the IC card, having a peripheral rim provided with recesses at opposite ends of the front portion thereof, a terminal protecting member of the IC card, having a terminal protecting part for protectively covering the terminal array, and legs extending from the opposite longitudinal sides of the terminal protecting part and held at respective free ends thereof on the frame of the IC card. A body of the connector has guide legs for guiding the IC card upon inserting the IC card in the connector. Lifting devices provided in the body of the connector enter the recesses of the frame to lift up the terminal protecting part of the terminal protecting member when the IC card is inserted in the connector.

Abstract: An arrangement including an appliance and an optional support. The electrical appliance has a vessel; an electrical device is mounted centrally on the bottom of the vessel together with an electrical control so as to be protected in a hollow base below the bottom. Mechanical actuator mechanism extends from the base to a position convenient for manual actuation. The base may be stood on the support so that electrical terminal pins engage in electrical supply sockets in the support, and the support may incorporate a supply switch to isolate the sockets when the appliance is lifted.

Abstract: A connector assembly comprises a female connector having a protruding portion extending from one end and with one or more sockets therein and a male connector having one or more pins for being received in a different one of the sockets and a retractable pin shield member in which the pins are recessed when the shield member is in a forward position. The pin shield member includes a cavity for receiving the protruding portion of the female connector and as the connectors are progressively engaged the protruding portion is urged against the shield member causing it to become gradually retracted and exposing the pins which are then progressively received in the sockets of the female connector.

Abstract: The disclosure herein describes a safety guard which comprises a cover with openings adapted to be mounted over an electrical wall outlet and closure elements which are slideably mounted to the cover to expose or to cover the openings in registry with sockets of the wall outlet. The cover and the closure elements are structured so as to require two movements to displace the closure elements from a socket-covering position to a socket-exposing position. Also, a spring element connected between the cover and each closure element serves to bias the latter to the socket-covering position as the closure element is moved to expose the opening.

Abstract: A memory card having: a card-like package; a semiconductor module disposed within the package; a plurality of electrode terminals mounted on the package for allowing an external electrical connection of the semiconductor module in the package to an external circuit, the electrode terminals including an earth electrode terminal; a metallic shutter disposed on the package and movable between an open position in which the electrode terminals are exposed for the electrical connection and a closed position in which the electrode terminals are covered; an electrically conductive spring having one end electrically connected to the shutter and the other end secured to the package for biasing the shutter toward the closed position; and a conductor for electrically connecting the other end of the spring to the earth electrode terminal.

Abstract: An automatic protection cap assembly for plug and receptacle connectors including a laterally fixed apertured plate and a laterally slidably apertured plate in each connector. The plates of the receptacle connector are axially movable. Opening and closing cams having inclined ramp surfaces are fixed on laterally opposite sides of the housing of the receptacle. A latch mounted on the slide plate of the receptacle is insertable into a latch recess in the plug housing, and the latch and latch recess cooperate for moving the slide plate to its closed position by axially moving the plate assembly of the receptacle upon demating of the assembly.

Abstract: In a hand-held broadcast means of communications technology, the charging device for the integrated battery is connected via a covered plug. The cover of the plug is automatically opened when the hand-held broadcast device is placed onto the charging device and the path for the cooperating plug of the charging device is thus exposed.

Abstract: A lampholder for a screw-in lightbulb has a body supporting two cable terminals for connection to an electrical supply, and a contact carrier mounted on the body and defining a bulb receiving socket, the contact carrier being movable between first and second positions relative to the body in a direction parallel to the insertion direction of a bulb and supporting terminals which connect an inserted bulb to the cable terminals when the carrier is in the first position but are spaced from the cable terminals when the carrier is in the second position. A spring pushes the carrier to the second position. When a bulb is screwed part-way into the carrier socket it bears against a fixed abutment so that the carrier is moved from the second to the first positions as the bulb is screwed fully into the socket.

Abstract: An external memory pack has a circuit board having an electrical contact, a case for covering the circuit board, an opening formed in the case to expose the electrical contact of the circuit board, a slidable shutter for opening and closing the opening and an actuator for actuating the shutter for sliding.

Abstract: An electric socket outlet is provided with an outer shutter (20) mounted slidably on the socket fascia (11) and movable between a closed position in which it covers and hides from view the openings (16-18) in the fascia through which the plug pins enter, and an open position in which the openings are uncovered. The shutter is received in a recess (14) in the fascia so that its front surface is flush with that of the fascia, and is biased to the closed position by a spring (25). A switch may be included and an interlock device provided to prevent the switch being turned on when there is no plug inserted in the socket and to ensure the switch is turned off when a plug is removed from the socket.

Abstract: A jack for a telephone set comprises a dust-proof closure unit having a first cover plate provided with a guide groove extended in a sliding direction and a second cover plate provided with a guiding projection engageable in the guide groove of the first plate, the first and second cover plates being arranged slidable relative to each other along a plug receiving aperture in a casing of the jack to close or open the aperture, whereby the first and second cover plates of the closure unit can be retracted as overlapped with each other to their aperture opening position so as to reduce their retractive dimension substantially to be half in the sliding direction, and the dust-proof closure unit can be provided for the plug receiving aperture without any increase in size of the casing.

Abstract: Electrical socket apparatus, for example, for safety supporting and supplying electricity to an electrical appliance, which are provided with at least live and neutral terminal pins. The apparatus includes locating means which are engageable by the electrical appliance to locate the appliance in a predetermined position, live and neutral sockets to receive the live and neutral terminal pins, electrical conductors in the sockets, switch means which are actuable by the electrical appliance being placed in a predetermined position to make an electrical connection to at least one of the electrical conductors, and a displaceable member which projects into the sockets and is movable against a bias to actuate the switch means, to prevent risks, e.g. electric shocks and overheating of contacts, and to hinder misuse of the apparatus.

Abstract: A control panel supports and positions interchangeable subunit electronic devices and provides a neat and uniform outwardly facing surface. When subunit electronic devices are disconnected from the control panel, cover plates extend and conform to the uniform outwardly facing surface. Hinged support members "lock" in an over center position to rigidly support each cover plate. Electrical connectors protruding from each subunit electronic device "unlock" the hinged support members from the over center position when the subunit electronic device is urged toward the cover plate.

Abstract: An electric socket outlet is provided with an outer shutter (20) mounted slidably on the socket fascia (11) and movable between a closed position in which it covers and hides from view the openings (16-18) in the fascia through which the plug pins enter, and an open position in which the openings are uncovered. The shutter is received in a recess (14) in the fascia so that its front surface is flush with that of the fasica, and is biased to the closed position by a spring (25). A switch may be included and an interlock device provided to prevent the switch being turned on when there is no plug inserted in the socket and to ensure the switch is turned off when a plug is removed from the socket.