Multi-conductor electrical distribution system

Abstract

 The multi-conductor electrical distribution system includes an elongate housing 10′ with a plurality of entry points 18′ along its length. Within the elongate housing 10′ six busbars 54a-f are provided and an intermediate housing 23′ comprising a socket outlet 57, a connector support member 58 and a conductor support member 59 at each entry point. The busbars 54a-f provide at least two live conductors for ac electricity. Connector means 73 are provided for providing electrical connection from the socket outlet 57 to one of the live conductors at each entry point 18′ whereby current may be drawn from a first live conductor at a first entry point and at a separate second entry point current may be drawn from a second separate live conductor. In this manner, attachment of appliances to the distribution system does not necessitate authorised or qualified personnel, the risk of drawing unbalanced power from the system is reduced and the distribution system may be used with any standard socket configuration and corresponding standard appliance plug.

Description

[0001] The present invention relates to a multi-conductor electrical distribution system of the kind comprising an elongate channel within which a plurality of continuous electrical conductors are provided. Access to the continuous electrical conductors is by means of a series of entry points in the channel into any one of which a contact plug may be inserted. The electrical distribution system is suitable for domestic, commercial and industrial use or the like.

[0002] Many different electrical distribution systems are known for use in the situations identified above. An example of such a known system is described and claimed in British patent No. 2095049. This system has the disadvantage that official regulations limit the amount of current which may be drawn from one electrical conductor and so imposes a limit on the amount of current the system can safely supply. The provision of more than one electrical conductor from which current may be drawn in an electrical distribution system introduces an equivalent increase in the maximum amount of current which can be drawn from the one system.

[0003] A known system which provides more than one electrical conductor from which current may be drawn has an elongate channel within which is located three separate electrical conductors or busbars. In order to draw current from one of the three electrical conductors a plug is used which is adapted so that when it is inserted into the channel it is brought into contact with all three electrical conductors. Since current is only to be drawn from one of the electrical conductors the plug has a switch for selecting from which one of the three electrical conductors current is to be drawn. The switch is operated by the user. In an alternative known system, three different plugs must be used each of which is adapted for connection to only one of the three electrical conductors respectively but can be used with any socket. A disadvantage of these known systems is that since the selection of which electrical conductor current is to be drawn from is made by the user, there is the possibility that too many plugs will be connected to any one electrical conductor, thus overloading the system. Furthermore, because of this problem only authorised or qualified people can connect appliances to the electrical system. Moreover, it will be appreciated that it is important to ensure that the power drawn from the distribution system is as evenly balanced as is practicable. However, there is a risk with these known systems that unbalanced power may be drawn from the system by a user's inadvertent preference for a particular one or two of the electrical conductors.

[0004] The present invention seeks to overcome the above mentioned disadvantages and provides an improved multi-conductor electrical distribution system in which at any entry point electrical access to only one of the electrical conductors from which current may be drawn is available.

[0005] According to the present invention there is provided a multi-conductor electrical distribution system comprising an elongate housing within which is provided a plurality of electrical conductors from more than one of which current may be drawn, the elongate housing having a plurality of entry points each for permitting electrical access of a contact plug to the electrical conductors; and enabling means at each entry point for enabling electrical contact between the contact plug and only a predetermined one of the current supply conductors, at least one enabling means enabling electrical contact with a first current supply conductor at a first entry point and at least one additional enabling means enabling electrical contact with a different current supply conductor at a separate entry point.

[0006] Thus, with the present invention, which current supply conductor is to be accessed at each entry point is predetermined during assembly of the system and so the risk of overloading the system when in use is minimised. Moreover, since the risk of overloading the system is so small it is not necessary for a person connecting an appliance to the system to be an authorised or qualified person and the risk of unbalanced power being drawn from the system is reduced.

[0007] Preferably, the plurality of electrical conductors are a plurality of busbars, the enabling means is in the form of connecting means which provide electrical contact between the contact plug and the predetermined one of the current supply conductors and within the elongate housing at each entry point an intermediate housing is provided on which the connector means is mounted. In this manner, complicated hardwiring of each entry point of the distribution system is dispensed with and the distribution system is easily and quickly assembled with the determination of which busbar to draw current from conveniently achieved during assembly of the system.

[0008] In a first embodiment the intermediate housing has a housing channel extending away from the entry point and electrical connector means mounted on the outside of the intermediate housing in the form of a clip member and resilient finger. Slots are provided in the intermediate housing to permit an adaptor plug inserted into the housing channel to contact with the clip member which is in electrical contact with the resilient finger which is in turn in electrical contact with one of the electrical conductors provided in the elongate housing.

[0009] Preferably, the intermediate housing is provided with a door member closing the entry point to the housing channel.

[0010] Advantageously, at least one shutter member is also provided with the intermediate housing to prevent accidental contact by a user with the electricity supply.

[0011] Furthermore, the socket outlet of the adaptor plug may conform to standard international configurations so that it may accept compatible standard plugs or alternatively the socket outlet of the adaptor plug may be unique in design for use with an intermediate power supply connector for supplying power to remote socket outlets.

[0012] In a second embodiment the intermediate housing includes a socket outlet and a connector support member in which the socket outlet has a cup member for receiving a contact plug, the base of the cup member having slots to permit electrical contact between a contact plug located within the cup member and the connector means. The connector support member may be in the form of a platform on which the connector means are mounted adjacent the socket outlet, the platform having connector slots to permit electrical contact between the connector means and the electrical conductors in the elongate housing. The intermediate housing may also include a conductor support member whereby the conductor support member and the connector support member define an inner housing within which the electrical conductors may be located.

[0013] With this embodiment a particularly convenient and simple multi-conductor electrical distribution system is provided and one which is particularly versatile because the distribution system can be used with any type of known or standard plug by using the appropriate compatible socket outlet at each entry point.

[0014] Preferably, the electrical conductors are sheathed in an electrically insulating cover member which is provided with cut-away portions to expose short sections of each of the electrical conductors and the conductor support member may be provided with channel wall members which define channels within which respective exposed sections of the electrical conductors may be located.

[0015] Additionally, a shutter member may be provided movable from a closed position in which the slots in the base of the cup member are obscured to an open position in which the slots in the base of the cup member are exposed.

[0016] In this manner a particularly safe and reliable multi-conductor electrical distribution system is provided.

[0017] In a third embodiment a multi-conductor electrical distribution system is provided wherein at each entry point a socket outlet is provided having a plurality of pin apertures for receiving the pins of a contact plug there being a pin aperture provided for each current supply conductor in the elongate housing and wherein the enabling means is in the form of a shutter movable from a closed position in which the pin apertures for the current supply conductors are obscured to an open position in which one of the pin apertures for a corresponding one of the current supply conductors is exposed.

[0018] With this system, a particularly simple arrangement is provided at each entry point for predetermining during assembly of the system which current supply conductor is to be accessed at each entry point. With this system different contact plugs having differing arrangements of pins are used for contacting with corresponding different current supply conductors. Preferably, the different entry points and the corresponding contact plugs are colour coded for ease of use.

[0019] For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

Figure 1 is an exploded isometric view of a first embodiment of a multi-conductor electrical distribution system according to the present invention,

Figure 2 is an isometric view of a portion of the housing of the multi-conductor electrical distribution system of Figure 1,

Figure 3 is a side view of an adaptor plug for use with the electrical distribution system of Figure 1,

Figures 4, 5 and 6 are vertical partial sectional views from the side, of three intermediate housings for use with the electrical distribution system of Figure 1,

Figures 4a, 5a and 6a show the three different intermediate connecting members provided on each of the intermediate housings of Figures 4 to 6,

Figure 7 is a vertical partial sectional view from within the intermediate housing of Figure 4 looking towards the socket,

Figure 8 is an exploded isometric view of a second embodiment of a multi-conductor electrical distribution system according to the present invention,

Figures 9a and 9b are exploded side views of alternative arrangements of intermediate housings for use with the electrical distribution system of Figure 8,

Figures 10a to 10c are cross-sectional drawings of the intermediate housing of Figure 9a when located within the elongate housing,

Figures 11a to 11i are diagrams showing various connection options possible with the electrical distribution system of Figure 8,

Figures 12a to 12d show further connection options of a multi-conductor electrical distribution system according to the present invention,

Figure 13 shows an additional connection arrangement for a multi-conductor electrical distribution system according to the present invention,

Figure 14 is an exploded isometric view of a third embodiment of a multi-conductor electrical distribution system according to the present invention, and

Figure 15 shows two shutter arrangements for the electrical distribution system of Figure 13.

[0020] With reference to Figures 1 to 7, these show a multi-conductor electrical distribution system of the continuous track type having an elongate housing 10 (Fig.2) having a back wall 11, a first side wall 12, an opposing second side wall 13 and a front wall 14. The housing 10 may be made of any suitable material such as metal or plastics. Ideally, the housing 10 is made from extruded or rolled metal in which case the housing 10 is earthed. The first and second side walls 12, 13 are formed as one unit with the front wall 14. The back wall 11 is formed as a separate unit and engages with overhanging portions 12a and 13a of the first and second side walls in a force fit.

[0021] As shown in Figure 2, the first and second side walls 12, 13 have outwardly projecting pairs of flanges 15 adjacent to the back wall 11, for receiving the edges of a back cover 16. The back cover 16 is used to mount the housing 10 in an appropriate manner on a wall or the like. Alternatively brackets may be used. Slots 17 are provided in the first and second side walls 12, 13 adjacent the front wall 14 for receiving finishing sections or further housings for supplying, for example, data or telephone communications. The front wall 14 has a series of entry points or socket apertures 18 spaced along its length (only one is shown in Figure 2).

[0022] Within the elongate housing two electrically insulated supports 19a, 19b (Fig.1) are mounted one on each of the first and second walls 12, 13 respectively. The insulated supports 19a, 19b may be made of any suitable non-conductive material. The insulated supports 19a, 19b may be made as one unit with the elongate housing 10 in an extruded plastics material. The insulated support 19a mounted on the first wall 12 has three channels within which first, second and third separate electrical conductors 20a, 20b, 20c in the form of busbars are located. Each of the three electrical conductors or busbars 20a, 20b, 20c acts as a live conductor. The electrical conductors 20a, 20b, 20c may supply either dc or ac electricity. If the electrical conductors 20a, 20b, 20c supply ac electricity, the electricity supplied by any one of the electrical conductors 20a, 20b, 20c may be in phase with the electricity supplied by the other two electrical conductors or the electricity supplied may be advanced or retarded in phase with respect to the phases of electricity supplied by the other two electrical conductors. With this electrical distribution system, ac electricity is supplied by the electrical conductors 20a, 20b, 20c.

[0023] The insulated support 19b mounted on the second side wall 13 similarly has three channels within two of which, fourth and fifth electrical conductors or busbars 21, 22 are located. The channel adjacent the back wall 11 of the insulated support 19b is spare and may be used to supply additional communication or signalling lines. The fourth electrical conductor 21 located in the channel adjacent the front wall 14 functions as a neutral conductor for the ac electrical supply. The fifth electrical conductor 22 located in the central channel functions as an earth conductor for the ac electrical supply.

[0024] Three separate intermediate housings 23 are shown in Figure 1 which are located within the elongate housing adjacent respective socket apertures 18 in the front wall 14 of the elongate housing. Each intermediate housing 23 has a front wall 23a and a back wall 23b and a housing channel 24 which, with the intermediate housing 23 in position within the elongate housing 10, extends from an intermediate socket aperture 18 in the front wall 23a towards the back wall 23b.

[0025] Within the housing channel 24 (Figs. 1 & 7) there is a door 25 which corresponds in shape to the intermediate socket aperture 18 and is movable between a closed position when the door 25 is adjacent the intermediate socket aperture 18a and an open position when the door 25 is distant from the intermediate socket aperture 18. The door further includes two lugs (not shown) which engage in corresponding grooves 24a, provided in the wall of the housing channel. The grooves 24a run parallel to the housing channel 24 and act as guides to the movement of the door 25 within the housing channel 24. The door 25 is connected by means of a biasing member in the form of a spring (not shown) to the back wall 23b. The spring is biased such that it acts to hold the door 25 in its closed position adjacent the intermediate socket aperture 18a when no external force is applied to the door.

[0026] On the outside of the intermediate housing 23 three open compartments are defined on either side of the housing channel 24 by four partitioning walls 26 and the front and rear walls 23a, 23b of the intermediate housing 23. Two partitioning walls 26 are mounted either side of the housing channel 24 with the three compartments so defined on one side being inverted with respect to the three compartments on the other side of the housing channel 24. The compartments are spaced along the length of the housing channel 24 and are provided for the mounting of electrical connector means on the intermediate housing 23. At the base of each partitioning wall 26 (Fig. 1) there is an intermediate connector slot 27. In addition, three intermediate housing slots (not shown) are provided in the wall of the housing channel. A first intermediate housing slot is located adjacent the central compartment on one side of the housing channel 24 and the second and third intermediate housing slots are located adjacent two compartments on the opposite side of the housing channel 24. In this embodiment, the second and third intermediate housing slots are adjacent the two compartments nearest the front wall 14 of the elongate housing 10. The intermediate housing slots are located parallel to the partitioning walls 26 and are provided to permit electrical contact between an adaptor plug inserted into the housing channel and the electrical selective connector means. The intermediate housing 23, the door 25 and the partitioning walls 26 are all made of an electrically insulating material such as a plastics material.

[0027] In order to allow electrical connection between an adaptor plug within the housing channel 24 and one of the first, second or third electrical conductors 20a, 20b, 20c, the electrical connector means is provided in the form of an intermediate connector 28. The intermediate connector 28 may be made of any suitable conductive material, for example bronze or some other conductive metal. The intermediate connector 28 may be in one of three forms: a first intermediate connector 28a for permitting connection to the first live conductor 20a, a second intermediate connector 28b for permitting connection to the second live conductor 20b or a third intermediate connector 28c for permitting connection to the third live conductor 20c. Each of the three intermediate connectors 28a, 28b, 28c are shown in Figures 4a, 5a and 6a respectively. The mounting of the three intermediate connectors on the intermediate housing 23 is shown respectively in Figures 4, 5, and 6.

[0028] Each intermediate connector 28a, 28b, 28c comprises a clip member 29 and a resilient finger 30. The clip member 29 is identical for each of the three intermediate connectors 28a, 28b, 28c and is in the shape of a "U" with the end portions of the "U" bent towards one another and extended downwards towards the inner base of the "U", so providing inner walls 31. The clip member 29 is resilient so that an electrical pin on a plug inserted between the inner walls 31 will cause the end portions of the clip member 29 to flex. In addition, the resilience of the clip member 29 ensures good electrical contact is established between the inner walls 31 of the clip member 29 and an electrical pin when inserted between the inner walls 31.

[0029] The resilient finger 30 of the intermediate connectors 28a, 28b, 28c may be connected to the clip member 29 in one of three different ways so as to form the three different intermediate connectors 28a, 28b, 28c. The resilient finger 30 is arcuate in shape and is of a sufficient length to extend from the clip member 29 when mounted on the intermediate housing 23 to one of the live conductors 20a, 20b, 20c. The finger 30 is resilient so as to ensure good electrical contact between the free end of the finger 30 and one of the live conductors 20a, 20b, 20c and to assist in the positioning of the intermediate housing 23 within the elongate housing 10.

[0030] The first intermediate connector 28a is shown in Figure 4a and as may be seen the resilent finger 30 is connected at its base to the base of the clip member 29 by a crank-shaped arm member 32. This ensures that the resilient finger 30 is offset in relation to the centre of the clip member 29. When the first intermediate connector 28a is mounted on the intermediate housing 23, as shown in Figure 4, the clip member 29 is located between the outside of the intermediate housing 23 and the edges of the partitioning walls 26 adjacent the intermediate housing. The resilient finger 30 occupies the compartment adjacent the front wall 23a of the intermediate housing 23 and the crank-shaped arm member 32 connects the resilient finger 30 to the clip member 29 by passing through the slot 27 in the partitioning wall 26 nearest the front wall 23a of the intermediate housing 23.

[0031] The third intermediate connector 28c is shown in Figure 6a, and as may be seen the resilient finger 30 is also connected to the clip member 29 by a crank-shaped arm member 32. However, with this connector the crank-shaped arm member 32 ensures the resilient finger is offset in relation to the centre of the clip member 29 in opposite orientation to the first intermediate connector 28a. As shown in Figure 6, the clip member 29 of the third intermediate connector 28c is mounted in the same fashion as for the first intermediate connector 28a. However, the resilient finger 30 of the third intermediate connector 28c is located in the compartment adjacent the back wall 23b of the intermediate housing 23 and the crank-shaped arm member 32 passes through the slot 27 in the partitioning wall 26 nearest the back wall 23b of the intermediate housing 23.

[0032] Turning now to Figure 5a, the second intermediate connector 28b has the resilient finger 30 connected to the base of the clip member 29 by means of a straight arm member (not shown). Thus, the resilient finger 30 is positioned parallel to the centre of the clip member 29. When the second intermediate connector 28b is mounted on the intermediate housing 23, as shown in Figure 5, the clip member 29 is mounted as described above with reference to the first and third intermediate connectors 28a, 28c. The resilient finger 30, however, is located within the central compartment defined by the two partitioning walls 26.

[0033] With all three intermediate connectors, the inner walls 31 of the clip member 29 are aligned with the first intermediate housing slot such that a pin inserted through the first intermediate housing slot may be inserted between and be engaged by the inner walls 31 of the clip member 29.

[0034] In order to achieve electrical contact between an adaptor plug within the housing channel 24 and the neutral and earth connectors 21, 22 electrical connector means are mounted on the opposite side of the housing channel 24 in the form of two further intermediate connectors 37 both of which correspond substantially in shape with the second intermediate connector 28b. The further intermediate connectors 37 are mounted respectively in the compartment adjacent the front wall 23a of the intermediate housing 23 and in the central compartment with the inner walls of the clip members of the further intermediate connectors 37 aligned with the second and third intermediate housing slots.

[0035] The resilient fingers of the further intermediate connectors 37 are in contact with the neutral and the earth conductors 21, 22 respectively. The clip member of the further intermediate connector 37 mounted in the central compartment is larger than the clip members of the other electrical connector means so that, when in use, contact is made with the larger clip member first and hence with the earth conductor 22. As will be seen from Figure 7, the further intermediate connectors 37 (only one shown) are mounted in an inverse orientation with respect to the mounting of the first, second or third intermediate connectors 28a, 28b, 28c, so that contact may be made with the electrical conductors 21, 22 on the second side wall 13 as opposed to the live conductors 20a, 20b, 20c mounted on the first side wall 12 of the housing 10.

[0036] In the interests of safety a first shutter 33 is provided outside and parallel to the wall of the housing channel 24 between the intermediate housing 23 and the clip member 29. The first shutter 33 has a shutter slot 34 towards the front end portion and a resilient arm 35 attached to the rear end portion. The free end of the resilient arm 35 abuts against the back wall 23b of the intermediate housing 23. The arm 35 on the first shutter 33 is sufficiently resilient to permit movement of the first shutter 33 parallel to the wall of the housing channel 24 from a closed position where the first intermediate housing slot is obscured by the first shutter 33 to an open position where the shutter slot 34 is aligned with the first intermediate housing slot and the inner walls 31 of the clip member 29. A cam surface (not shown) is provided on the first shutter 33 projecting towards the intermediate housing 23 for actuation of the first shutter 33. The resilient arm 35 holds the first shutter 33 in the closed position when the cam surface is not engaged.

[0037] A second shutter 36 is also provided outside the housing channel 24 on the opposite side to the first shutter 33. The second shutter 36 has two shutter slots (not shown) in the front end portion of the second shutter, a resilient arm on the rear end portion and a cam surface. The resilient arm and the cam surface correspond to the resilient arm 35 and the cam surface on the first shutter 33.

[0038] The second shutter 36 is movable by action against the cam surface between a closed position where the second and third intermediate housing slots are obscured by the second shutter 36 and an open position where the two shutter slots are aligned with the second and third intermediate slots and the inner walls of the clip members of the further intermediate connectors 37.

[0039] It will be appreciated that to further ensure contact is made initially to the earth conductor 22, the second shutter 36 may have only one shutter slot and an opening such that the intermediate housing slot to the earth conductor 22 is never obscured.

[0040] More than one intermediate housing 23 is provided in the elongate housing 10 adjacent respective sockets 18. As may be seen in Figure 2, the intermediate housings 23 have first, second and third intermediate connectors 28a, 28b, 28c mounted on sequential housings 23. Additional intermediate housings 23 would commonly be provided with intermediate connectors 28a, 28b, 28c in a similar sequential arrangement within the elongate housing 10 until the maximum number of sockets permissible for each live conductor 20a, 20b, 20c is reached. Other arrangements of the preselected connections to the live conductors 20a, 20b, 20c at the entry points are of course possible. However, it has been found that by arranging the preselected connections sequentially the risks of unbalancing the power drawn from the multi-conductor electrical distribution system are reduced.

[0041] In order to put together the electrical distribution system, the five electrical conductors are mounted in the insulated supports 19a, 19b. The first, second and third intermediate connectors are mounted on the intermediate housing 23 in the arrangement outlined above with the first intermediate conductor 28 on one side and the two further intermediate conductors 37 on the opposite side, each adjacent an intermediate housing slot. The intermediate housings 23 with the intermediate connectors 28, 37 are then inserted into the elongate housing 10 from the back, so that the resilient fingers of the intermediate connectors 28, 37 come into contact with the appropriate electrical conductors 20, 21, 22. Once in position the resilient fingers of the intermediate connectors 28, 37 ensure that the intermediate housings 23 are firmly held in position. The back wall 11 of the elongate housing 10 is then finally fitted between the overhanging portions 12a, 13a to close the elongate housing 10. The electrical distribution system may now be mounted in an appropriate manner on a wall or the like.

[0042] An adaptor plug 38 is used for connecting an appliance to the power supply. The adaptor plug 38 is shown in Figure 3 and comprises a female connection portion 39 for receiving the plug of an appliance and a male connection portion 40 which bears three pins 41′ 41˝, 41˝′ for connection to the neutral conductor 21, earth conductor 22 and one of the live conductors 20 respectively. As may be seen in Figure 3, the pin 41˝′ for connection to one of the live conductors 20 is provided on one side of the male connection portion 40 with the two further pins 41′, 41˝ for connection to the neutral and earth conductors 21, 22 provided on the opposite side.

[0043] When in use, the male connection portion 40 of the adaptor plug 38 is inserted into a socket aperture 18. The end of the male connection portion 40 abuts against the door 25 and as the male connection portion 40 is pushed into the housing channel 24 the door 25 is forced to move back, against the action of the spring, towards the back wall 23a of the intermediate housing 23. The door 25 moves along the housing channel 24 guided by the lugs which are in engagement with the grooves 24a provided in the housing channel wall. The male connection portion 40 is inserted with the three pins 41′, 41˝, 41˝′ parallel to the partitioning walls 26.

[0044] Once the male connection portion 40 is fully inserted, the adaptor plug 38 is rotated clockwise and the pin 41˝′ engages the cam surface provided on the first shutter 33 and the further pin 41˝ engages the cam surface on the second shutter. As the adaptor plug 38 is further rotated, the pin 41˝′ acts against the cam surface to cause the first shutter 33 to move backwards against the action of the resilient arm 35. A similar action occurs with the second shutter also. All pins 41 then pass through the intermediate slots provided in the intermediate housing 23. Initially, the pin 41˝ is forced between the inner walls of the clip member of the further intermediate connector 37 mounted in the central compartment since, as mentioned above, the clip member is larger for the earth connection. The shutter slot 34 also lines up with the first intermediate housing slot allowing the pin 41˝′ to pass through the slots and be forced between the inner walls 31 of the clip member 29 for connection with one of the live conductors 20 and, in the same manner, the pin 41′ engages with the further intermediate connector 37 located in the compartment nearest the front wall 14 for connection with the neutral conductor 21.

[0045] For disconnection of the appliance from the power supply, the adaptor plug 38 is turned anticlockwise approximately 90° and removed from the housing channel 24. The door 25 and both first and second shutters, 33, 36 return to their original positions by the action of the spring and the resilient arms 35 respectively.

[0046] Thus, it will be appreciated that the same adaptor plug may be used with all the entry points of this multi-conductor distribution system since the live conductor which supplies electricity at any one entry point is predetermined during assembly of the system. Moreover, any overloading of the system is minimised since the connection at each entry point to one of the current supply conductors is predetermined. Furthermore, the female connection portion 38 may be any standard socket outlet to receive the compatible plug of the appliance. Hence, the distribution system is particularly versatile since it may be used with a large range of different types of standard plugs.

[0047] With reference to Figures 8, 9a, 9b, 10a, 10b and 10c an alternative multi-conductor electrical distribution system of the continuous track type is shown having an elongate housing 10′ having a back wall 11′, a first side wall 12′, an opposing second side wall 13′ and a front wall 14′. The housing 10′ may be made of any suitable material such as metal or plastics. Ideally, the housing 10′ is made from extruded aluminium or rolled steel section in which case the housing 10′ is earthed.

[0048] In Figure 8 side members 51, 52 are provided on the edges of and project outwardly from the rear wall 11′ to form a shallow channel. The side members 51, 52 terminate in curved portions 51a, 52a. Cooperating curved portions 53a are provided on the first and second side walls 12′, 13′. The housing 10′ is formed by locating the first and second side walls 12′, 13′ over the side members 51, 52 with the curved portions 51a, 52a of the side members 51, 52 in engagement with the curved portions 53a of the first and second side walls 12′, 13′ in a force fit. Ideally, and as shown in Figure 8, the curved portions 53a do not extend over the whole of each of the respective first and second side walls 12′, 13′. The curved portions 53a are located approximately centrally in the first and second side walls 12′, 13′ so that the first and second side walls 12′, 13′ overlap a substantial portion of the side members 51, 52 beyond the curved portions 51a, 52a. The first and second side walls 12′, 13 may be formed as one unit with the front wall 14′ and similarly the side members 51, 52 may be formed as one unit with the rear wall 11′. The housing 10′ may be mounted on a wall, ceiling or under the floor in a similar manner to that described with reference to the first embodiment shown in Figures 1 to 7 and may also have additional finishing sections as described earlier.

[0049] Alternatively, as shown in Figures 9a, 9b, 10a, 10b and 10c the side members 51, 52 may be extended and folded over outwardly to form resilient catch members 51b, 52b which engage in the spaces 53b formed between the curved portions 53a of the side walls 12′, 13′ and their free edges.

[0050] The front wall 14′ has a series of entry points or socket apertures 18′ spaced along its length, only one of which is shown in Figure 8.

[0051] A plurality of electrical conductors, in Figure 8 six electrical conductors or busbars 54a-f are shown, are provided within the housing 10′. The electrical conductors or busbars 54a-f are sheathed in an electrically insulating cover 55 and are mounted on the inner surface of the rear wall 11′ in the shallow channel between the side members 51, 52. The insulating cover 55 may be of any suitable non-conductive material and is preferably an extruded plastics material. The electrical distribution system may supply either dc or ac electricity. The distribution system shown in Figure 8 supplies ac electricity. Three of the electrical conductors 54a, 54b, 54e act as live conductors for the ac electrical supply, two further electrical conductors 54c, 54d act as earth and dedicated earth conductors and a sixth electrical conductor 54f acts as a neutral conductor. The three live conductors 54a, 54b, 54e may supply ac electricity which is in phase with the electricity supplied by each of the other conductors. Alternatively, any one of the three live conductors 54a, 54b, 54e may supply ac electricity which is advanced or retarded in phase with respect to the phases of electricity supplied by each of the other two live conductors.

[0052] The insulating cover 55 completely surrounds the electrical conductors 54a-f except for preselected cut-away portions 56 which expose short sections of individual electrical conductors. At least one section of each of the electrical conductors 54a-f is exposed for a respective entry point or socket aperture 18′ in the front wall 14′ of the housing 10′. It will be appreciated that in the interests of safety the electrical conductors have been sheathed in a non-conductive cover 55. However, the electrical conductors need not be sheathed and instead could be mounted on a non-conductive mount with the electrical conductors exposed along their whole length.

[0053] Each socket aperture 18′ has a respective intermediate housing 23 provided within the elongate housing adjacent the socket aperture 18′. One intermediate housing 23′ is shown in Figure 8 in an exploded form. The intermediate housing 23′ comprises a socket outlet 57, a connector support member 58 and a conductor support member 59.

[0054] The socket outlet 57 has a cup member 60 the external walls of which conform, but are slightly smaller than, the aperture of the respective socket aperture 18′ in the front wall 14′. The inner walls of the cup member 60 are shaped so as to slidably engage the exterior of a plug (not shown) when inserted into the cup member 60. Pin slots (not shown) are provided in the base of the cup member 60, through which pins on the plug may pass when the plug is inserted into the cup member 60. In Figure 8 openings 61, are also provided perpendicular to the length of the elongate housing in opposing walls of the cup member 60. A face plate or flange 62 is provided at an upper edge of and radiating outwardly from the cup member 60. The perimeter of the face plate 62 is greater than the aperture of the respective socket aperture 18′ whereby when the socket outlet 57 is inserted into the socket aperture 18′, the cup member 60 passes through the socket aperture 18′ until the face plate 62 engages with the front wall 14′ surrounding the socket aperture 18′ preventing further movement of the cup member 60 into the elongate housing.

[0055] The socket outlet 57 may conform to any standard socket outlet so that compatible standard plugs may be used to connect appliances to the power supply without the need of a separate adaptor plug. Thus, this distribution system is both convenient and versatile for connecting appliances to the power supply.

[0056] In Figures 9a, 9b, 10a, 10b and 10c the socket outlet 57 also has a downwardly projecting catch member 57′ for engagement with the walls of the connector support member 58.

[0057] The conductor support member 59 is positioned between the electrical conductors 54a-f and their insulating cover 55 and the rear wall 11′. The conductor support member 59 has a base 63 on which upstanding channel wall members 64 are provided. The channel wall members 64 are arranged so as to form short conductor receiving channels 65 which correspond in size and position with the cut-away portions 56 in the insulating cover 55 for a respective socket aperture 18′. When in position within the elongate housing the channel wall members 64 project through the cut-away portions 56 in the insulating cover 55 so that a channel wall member 64 is located either side of each section of exposed electrical conductor for the respective socket aperture 18′ and each exposed electrical conductor is located in one of the conductor receiving channels 65 defined by the channel wall members 64. Alternatively, the channel wall members 64′ may be provided on the base of the platform 66 of the connector support member 58′ as shown in Figures 9a, 9b, 10a, 10b and 10c.

[0058] When in position within the elongate housing, the connector support member 58 is located between the electrical conductors 54a-f and their insulating cover 55 and the socket outlet 57 and is in alignment with a respective socket aperture 18′ and the corresponding exposed portions of the electrical conductors 54a-f.

[0059] The connector support member 58 has a platform 66 which is divided by upstanding partitioning wall members 67 into three parallel connector receiving channels 68a, 68b and 68c which lie perpendicular to the length of the elongate housing. The two outermost partitioning wall members 67 each have on an upper edge a resilient holding member 69 in the form of a lip having a cam surface 70 which terminates in a downwardly facing abutment surface 71. The lips 69 are shaped so as to fit snugly within the openings 61 in the cup member 60 of the socket outlet 57. In order to attach the socket outlet 57 to the connector support member 58 the cam surfaces 70 on each of the lips 69 are brought into engagement with the outer wall of the cup member 60. The two opposing lips 69 are sufficiently resilient that downward pressure by the cup member 60 on the cam surfaces 70 forces the lips 69 to flex thus permitting the cup member 60 to pass between the lips 69. Once the lips 69 are aligned with the openings 61 the lips 69 relax back into their normal position. The downwardly facing abutment surfaces 71 on the lips 69 then come into contact with the lower edges of the openings 61 and in this manner inadvertent separation of the connector support member 58 from the socket outlet 57 is prevented.

[0060] As shown in Figures 9a and 9b the lips 69′ may have cam surfaces 70′ for outward resilient engagement with the rim of the socket aperture 18′ and which, when in position, are freely located below the rim of the socket aperture 18′.

[0061] Each of the connector receiving channels 68a, 68b and 68c has at least one connector slot 72 in the platform 66 of the connector support member 58 lying parallel to the length of the elongate housing. The connector slots 72 permit access from the connector receiving channels 68a-c to the exposed sections of the electrical conductors 54a-f. One of the connector receiving channels 68a has only one connector slot which, when in position in the conduit, is aligned with the exposed section of the neutral conductor 54f. A second of the connector receiving channels 68c has three connector slots 72 which, when in position in the elongate housing, are aligned with the exposed sections of each of the three live conductors 54a, 54b and 54e. The third of the connector receiving channels 68b has two connector slots 72 which, when in position in the elongate housing, are aligned with the exposed sections of each of the two earth conductors 54c and 54d. Preferably, as shown in Figure 8, the connector receiving channel 68b for supporting the earth connector is located between the receiving channels for the live and neutral connectors so that the live and neutral connectors are separated as much as possible. The sides of the connector slots 72 are bevelled. Two downwardly projecting conductor side walls 66a are provide on the base of the platform 66 parallel to the length of the elongate housing. The conductor side walls 66a are located such that the electrical conductors 54a-f, their insulating cover 55 and the conductor support member 59 may be positioned between the conductor side walls 66a. Thus, the electrical conductors 54a-f and their insulating cover 55 are housed within an inner housing defined by the platform 66 and the conductor side walls 66a of the connector support member 58 and the base 63 of the conductor support member 59. The base of the platform 66 of the connector supply member 58 also has downwardly projecting corresponding channel wall members (not shown) which cooperate with the channel wall members 64 on the conductor support member 59 to separately enclose each of the electrical conductors 54a-f. The conductor support member 59 and the connector support member 58 engage one another in a manner similar to that described for the engagement of the connector support member 58 and the socket outlet 57.

[0062] The socket outlet 57, the connector support member 58 and the conductor support member 59 may all be made from any suitable electrically insulating material, ideally a plastics material.

[0063] Connector means in the form of electrical connectors 73 are mounted in each of the three connector receiving channels 68a-c. The connectors 73 for connection to the live and neutral conductors 54a, 54b, 54e, 54f each have a clip member 74 for receiving a pin from a plug inserted into the socket outlet 57. The clip member 74 is similar to the clip member 29 of the first embodiment and is in the shape of a "U" with the end portions of the "U" being bent towards one another and extended downwards towards the inner base of the "U" to provide inner wall surfaces. The end portions of the "U" on which the inner wall surfaces are provided are curved so as to form between them an opening slightly smaller than the pin of a plug. The clip member 74 is resilient so that when the pin of a plug is inserted between the inner wall surfaces, in the opening formed by the curvature of the end portions of the "U", the end portions flex to allow insertion of the pin and ensure good electrical contact between the pin and the inner wall surfaces.

[0064] The connectors 73 for the live and neutral conductors 54a, 54b, 54e, 54f also have a resilient finger 75 which is connected to or is integral with the clip member 74. The finger 75 is in the form of a metal strip which is doubled over and is of a thickness such that the double layer of metal strip is able to pass through the connector slots 72 in the connector support member 58. The metal strip of the finger 75 tends against being folded over and so the finger 75 fits snugly and securely within the connector slot 72 and ensures good electrical contact with the electrical conductors. The bevelled sides of the connector slots 72 aid in the insertion of the finger 75 through the connector slot 72.

[0065] When in position, the free end of the finger 75 passes through a connector slot 72 to contact with an exposed section of one of the electrical conductors 54a, 54b, 54e, 54f. The finger 75 may extend directly from the clip member 74 or may be connected by means of an intermediate arm member 76. The clip members 74 are positioned centrally in the connector receiving channels 68a, 68c, and are in electrical contact with either one of the live conductors 54a, 54b, 54e or the neutral conductor 54f by means of the finger 75 and if necessary the intermediate arm member 76. With the intermediate arm member 76, the finger 75 can be inserted into a connector slot 72 distant from the central position in the connector receiving channel for example for connection to the neutral conductor 54f in Figure 8.

[0066] The earth connector 73 for connection to one of the earth conductors 54c, 54d has a resilient finger 75 for contact with one of the earth conductors 54c, 54d but in Figure 8 does not have a clip member. The earth connector 73 in Figures 8 and 9a is extended with a crank-shaped earth contact 77 so as to engage in a slot 78 provided in the cup member 60 of the socket outlet 57. The free end of the earth contact 77 is folded over to ensure good electrical contact with a side-wipe earth on a plug inserted into the socket outlet 57. In Figures 8 and 9a and for example 11a opposing crank-shaped earth contacts 77 are provided on the earth connector 73 for engagement in opposing slots 78 provided in the cup member 60. It will be understood that different earth connectors 73 may be provided depending upon the type of socket required, for example, the earth connector 73 may terminate within the connector receiving channel 68b, alternatively, the earth connector 73 may be provided with a clip member 74 similar to those of the live and neutral connectors 73. In a further alternative the earth connector 73 may be provided with rod 77a, as shown in Figure 9b, which projects away from the connector support member 58 through the base of the cup member 60 so as to project into the plug receiving space of the socket outlet 57.

[0067] The width of the metal strip of the connectors 73 is slightly less than the width of the connector receiving channels 68a, 68c and so the connectors 73 fit snugly within the connector receiving channels 68a-c. The connectors 73 may be made of any suitable electrically conductive material for example copper.

[0068] A shutter 79 is also provided on the base of the cup member 60. The shutter 79 has two pin cam surfaces 80 located directly below the pin slots in the base of the cup member 60 and directly above the clip members 74 of the live and neutral connectors 73. The shutter 79 is mounted in runners (not shown) and is capable of sliding movement along the runners from a closed position where the pin slots in the cup member 60 are obscured to an open position where the pin slots are exposed. Biasing means (not shown) in the form of a spring or resilient arm is connected to the shutter 79 to ensure that the shutter 79 remains in the closed position unless acted on by an external force. The runners for the shutter 79 may be defined by the upper free edges of the partitioning wall members 67 of the connector support member 58 and the spring or resilient arm may be attached at one end to the shutter 79 and at its opposing end to the connector support member 58.

[0069] When in use, a plug is inserted into the socket outlet 57, the live and neutral pins on the plug pass through the pin slots in the base of the cup member 60 and engage with the pin cam surfaces 80 on the shutter 79. Further force on the pin cam surfaces 80 moves the shutter 79 into the open position. The live and neutral pins on the plug then engage with the clip members 74 on the live and neutral connectors 73 which are in turn in electrical contact with exposed sections of one of the live conductors 54a, 54b, 54e and the neutral conductor 54f respectively. At the same time, with the embodiment shown in Figure 8, the side wipe earth on the plug is brought into contact with the earth connector 73 through the slot 78. The side wipe earth of the plug is brought into contact with the earth connector 73 before electrical contact is made with either the live or the neutral connectors 73 because the earth connector 73 extends into the slot 78 provided in the side of the cup member 60.

[0070] As will be appreciated from the above description, the live conductor from which current is to be drawn at any one entry point is predetermined during assembly of the system dependent upon which of the three live conductors 54a, 54b, 54e the live connector 73 is in contact with. Thus, with this electrical distribution system using different connectors 73 on separate connector support members 58 for separate entry points, electrical connection to different live conductors may be achieved at the separate entry points. As described in relation to the first embodiment, sucessive entry points of the electrical distribution system may supply in turn current from the three different live conductors. In this way no technical knowledge is required to connect an appliance to the electrical distribution system since each entry point has a predetermined power supply and so it is not necessary to restrict the connection of appliances to the system only to authorised or qualified personnel since the risk of overloading the system is minimised. In addition, it has been found that by sequentially arranging the predetermined power supply of each entry point the risk of unbalanced power being drawn from the system is reduced.

[0071] Figures 11a to 11i show diagrammatically the different connections which can be achieved with this electrical distribution system. In Figure 11a, the live connector is shown connected to a first live conductor 54a, the neutral connector to the neutral conductor 54f and the earth connector, which has opposing crank-shaped earth contacts, connected to a first earth conductor 54c. In Figure 11b the arrangement is the same except that the earth connector is connected to a second earth conductor 54d which may be a dedicated earth. Thus, the arrangement of Figure 11b would be particularly useful for appliances such as computers etc where a dedicated earth is required. In Figure 11c the arrangement is again the same except, instead of opposing crank-shaped earth contacts, the earth connector is connected to the first earth conductor 54c and is in the form of a projecting rod which is intended to project through the base of the cup member 60. With the arrangement shown in Figure 11c the corresponding contact plug is provided with a recess into which the rod slides when the contact plug is inserted into the socket outlet. Figures 11d and 11e correspond to Figures 11a and 11b except that the live connector is connected to a third live conductor 54e. In Figure 11f, two rod-type earth connectors are shown and this arrangement may be used where one of the earth conductors is used as a signal line for computer hardware, for example to communicate with other appliances. In Figure 11i a rod-type earth is again shown but in this Figure it is connected to the second earth connector 54d which, as mentioned above, may be a dedicated earth. In addition to the arrangements shown in Figures Ila to 11i, instead of two earth conductors and one neutral conductor, two neutral conductors may be provided and only one earth conductor which are busbars. A second earth contact may also be achieved by utilising the earthing of the elongate housing. With this arrangement seven connections are available.

[0072] Furthermore, in Figures 12a to 12d a multi-conductor electrical distribution system is shown in which two live conductors 54a and 54f, two earth conductors 54c and 54d and two neutral conductors 54b and 54e are provided. In addition, the earth connectors in Figures 12a to 12d include clip members similar to those provided on the live and neutral connectors. Thus, in Figure 12a the neutral connector is connected to the first neutral conductor 54b, the earth connector is connected to the second earth conductor 54d and the live connector is connected to the first live conductor 54a. In Figure 12b the same arrangement is shown except that the earth connector is connected to the dedicated earth 54c. In Figure 12c the second neutral conductor 54e and the second live conductor 54f are being used with the dedicated earth 54c, whereas in Figure 12d both the dedicated earth 54c and the second earth conductor 54d are in use, for example with computers for a signal line.

[0073] In Figure 13 a multi-conductor electrical distribution system is shown in which three live conductors 54a, 54b and 54c are provided, two neutral conductors 54d and 54e and two earth conductors 54f and 54f′ are provided with one of the earth conductors 54f′ being a housing earth. With this system standard sockets A may have their own live conductor 54a, a shared neutral conductor 54d and the housing earth 54f′ and separate standard sockets B also have their own live conductor 54b share the neutral conductor 54d with standard sockets A and the housing earth 54f′. Moreover, this system also provides for clean/dedicated sockets C which have their own live conductor 54c, their own neutral conductor 54e and their own clean earth conductor 54f.

[0074] From the above it will be seen that the multi-conductor electrical distribution system is particularly versatile in view of the numerous different power supply arrangements possible which may be predetermined during assembly of the system and where the electrical conductors are in the form of busbars the attachment of the connector means is both quick and convenient.

[0075] A further alternative multi-conductor electrical distribution system of the continuous track type is shown in Figures 14 and 15. The same elongate housing 10′ as that of Figure 8 is used including the same means for securing the front wall 14′ to the back wall 11′ to form the elongate housing 10′. As with the systems described earlier, a plurality of electrical conductors 54 are provided within the elongate housing 10′ mounted on a conductor support member 59′ on the back wall 11′. The electrical conductors 54 are sheathed 55 in insulating material. Portions 56 of the conductors 54 are, however, exposed in order that the pins of a contact plug may be brought into electrical contact with the exposed portions 56′. The conductor support member 59′ has channel wall members 64′ which define conductor receiving channels 65′ for individual conductors 54.

[0076] At each entry point or socket aperture 18′ a socket outlet 81 is provided. The socket outlet 81 has a plurality of pin apertures 82 which correspond in number with the number of electrical conductors 54 in the housing. The pin apertures 82 permit access for the pins on a contact plug to the exposed portions 56 of the electrical conductors.

[0077] Adjacent the socket outlet 81 and between the socket outlet and the electrical conductors a shutter 83 is provided. The shutter 83 has a resilient arm 84 or spring which biases the shutter 83 to its closed position in which at least all the pin apertures 82 in the socket outlet 81 which provide access to the live conductors are obscured. The shutter 83 has cam surfaces (not shown) engageable by the pins of the contact plug so that when a contact plug is inserted into the socket outlet 81 the pins on the contact plug engage the cam surfaces on the shutter 83 and cause the shutter 83 to move to its open position. When the shutter 83 is in its open position, one of the pin apertures 82 in the socket outlet 81 corresponding to one of the live conductors is exposed whereas the pin apertures to the other live conductors remain obscured. In so far as the neutral and earth conductors are concerned the pin apertures to these may also be accordingly obscured and exposed by the shutter 83. Alternatively, the shutter may be designed such that the pin apertures to the earth conductors are never obscured.

[0078] Hence, at any given socket aperture 18′, access to only one of the live conductors is available. Thus, in a manner similar to that described earlier with reference to the alternative electrical distribution systems, different shutters 83 are used at different socket apertures 18′ so that access to each of the live conductors in turn is possible and this is repeated sequentially until the maximum load which may be applied to any one conductor is reached. Furthermore, which live conductor any one socket aperture is accessible to is predetermined during assembly of the system.

[0079] It will be appreciated that with this electrical distribution system instead of the shutter having a predetermined arrangement of slots corresponding to the electrical conductors to which contact is to be made at a particular entry point, the socket aperture may instead have predetermined slots for providing access to only those particular electrical conductors to which contact is to be made for that particular entry point. Where it is the socket aperture which determines to which electrical conductors contact is to be made, different socket apertures are provided at different entry points so that contact may be made at the different entry points to the different live conductors in the elongate housing. In addition, the shutter need not have corresponding slots and instead may have an equal number of slots as there are electrical conductors so that the same shutter may be used at every entry point.

[0080] A contact plug 85 is shown, in an exploded form, in Figure 14. The contact plug 85 has a cover 86 which engages with a base 87. The base 87 has plug apertures 88 through which the pins 89 may be inserted. The base 87 has the same number and arrangement of plug apertures 88 as the socket outlet 81 has pin apertures 82. The pins 89 are arranged so that one pin will be an earth pin and will be brought into electrical contact with an exposed portion 56 of an earth conductor when the contact plug is inserted into a particular socket outlet. A second pin will be a neutral pin and a third pin a live pin. Each of these three pins are in turn connected by crimping or similar means to a corresponding wire in an appliance cable 90. The live pin may also be connected to a fuse 91, if necessary. Since different socket outlets provide access to different conductors different pin arrangements are needed for engagement with the different sockets. For ease of use corresponding socket outlets and contact plugs may be colour coded so that a red contact plug can be used with a red socket outlet but not a yellow or blue socket outlet which have their own colour coded contact plugs with different arrangements of pins.

[0081] It will be appreciated that the different connection options described earlier could be used with this system, the connections being predetermined during assembly of the system.

[0082] As will be appreciated, alternative arrangements of electrical connection means, electrical conductors and shutters for example could be incorporated in the electrical distribution systems described herein whilst still providing entry points with a power supply which is connected to selected electrical conductors in an electrical distribution system. Furthermore, the front, back and side walls of the housing may differ in both shape and in the manner in which they are connected together.

[0083] In this way, connection to one of a plurality of electrical conductors from which current may be drawn is achieved without the user being required to perform the selection of the electrical conductor and furthermore without the necessity of different adaptor plugs for connection to the different electrical conductors.

Claims

1. A multi-conductor electrical distribution system comprising an elongate housing (10; 10′) within which is provided a plurality of electrical conductors (20; 54) from more than one of which current may be drawn, the elongate housing (10; 10′) having a plurality of entry points (18; 18′) each for permitting electrical access of a contact plug (38; 85) to the electrical conductors (20; 54); and enabling means (23; 23′; 81, 83) at each entry point (18; 18′) for enabling electrical contact between the contact plug (38; 85) and only a predetermined one of the current supply conductors, at least one enabling means enabling electrical contact with a first current supply conductor at a first entry point and at least one additional enabling means enabling electrical contact with a different current supply conductor at a separate entry point.

2. A system as claimed in claim 1, wherein each electrical conductor from which current may be drawn (20; 54) is separately electrically accessed from at least one entry point (18; 18′).

3. A system as claimed in either of claims 1 or 2, wherein said enabling means is a connector means (73) which provides electrical contact between the contact plug and the predetermined one of the current supply conductors (54).

4. A system as claimed in claim 3, wherein there is provided within the elongate housing (10′) at each entry point (18′) an intermediate housing (23′) on which the connector means (73) is mounted, the intermediate housing (23′) including a socket outlet (57) and a connector support member (58).

5. A system as claimed in claim 4, wherein the socket outlet (57) includes a cup member (60) for receiving a contact plug and means for mounting the cup member (62) adjacent an entry point (18′), the cup member (60) having slots in its base to permit electrical contact between a contact plug located within the cup member (60) and the connector means (73).

6. A system as claimed in either of claims 4 or 5, wherein the connector support member (58) includes a platform (66) on which the connector means (73) may be mounted adjacent the socket outlet (18′).

7. A system as claimed in claim 6, wherein the platform (66) has a connector slot (72) to permit electrical contact between the connector means (73) and one of the live conductors (54) within the elongate housing (10′).

8. A system as claimed in claim 7, wherein the connector means (73) comprises a clip member (74) mounted on the platform (66) of the connector support member (58) and a resilient finger (75), the resilient finger (75) being attached at one end to the clip member (74) and located through the connector slot (72) for contact at the other end with one of the live conductors (54) provided in the elongate housing (10′).

9. A system as claimed in claim 8, wherein three selective connector means (73) are mounted on the platform (66) of the connector support member (58) for electrical contact separately with three electrical conductors within the elongate housing (10′), that is, with a live connector, a neutral conductor and an earth conductor and at least three separate connector slots are provided in the platform (66).

10. A system as claimed in any one of claims 4 to 9, further including a common contact plug adapted for insertion into any one of the socket outlets (18′) provided on the elongate housing (10′).

11. A system as claimed in claim 2, wherein at each entry point (18) a socket outlet is provided having a plurality of pin apertures (34) for receiving the pins of a contact plug (38) there being a pin aperture (34) provided for each current supply conductor (20) in the elongate housing (10) and wherein the enabling means is in the form of a shutter (33) movable from a closed position in which the pin apertures (34) for the current supply conductors are obscured to an open position in which one of the pin apertures (34) for a corresponding one of the current supply conductors is exposed.

Drawing