GB2161034A - Self-connecting lamp holder - Google Patents

Abstract

A self-connecting lamp holder for connecting a lamp in series in a lighting circuit comprises a mounting member, Fig. 1b, and a separate socket member, Fig. 1a. An external current conductor 31a, Fig. 1c, is accommodated in recesses 22 in the mounting member and is guided therethrough. The socket member and the mounting member are provided with complementary co- operating formations 42; 27a, 23a so that the socket member can be located in one or more predetermined orientations with respect to the mounting member. The socket member comprises a pair of protruding conductive terminals 15a, 15b and an insulating projection 18 disposed and adapted such that when the socket member is offered up to the mounting member in the predetermined orientation, the terminals connect automatically with the current conductor, and the insulating projection severs the current conductor between the terminals providing a series connection for the lamp holder. In a lighting system with two or more circuits the components of the lamp holder used in one circuit may be incompatible with those of other circuits. This ensures that a lamp holder intended for one circuit cannot inadvertently be connected into the wrong circuit. <IMAGE>

Description

SPECIFICATION Lamp holder for series-connected lighting circuits This invention relates to a lamp holder for connecting a lamp in series in a lighting circuit, and also relates to a lighting circuit comprising such a lamp holder. The invention further relates to a lighting system employing two such lighting circuits.

Lamp holders are used generally for connecting lamps into lighting circuits and for this purpose comprise conductive terminals to which external current connectors can be connected. Screw terminals are commonly used in which case a screwdriver is needed to make the connection. Moreover, if the current conductor is enclosed in an insulating sheath-as is usual-it will also be necessary to use a wire stripping tool to remove a portion of the insulation and thereby expose the conductor before connection is possible. In addition, especially when two or more lamps are to be connected in series, it is important to know which terminals of the lamp holder have to be connected to which conductors of the circuit.

Connection is simplified if so-called insert contacts are used instead of screw terminals.

These provide a push-fit connection facility for the current conductors. A lamp holder comprising insert contacts is shown on page 311 of the Philips Lighting Catalogue entitled "Comprehensive Hand Book 1 984", available from Philips Lighting, P.O. Box 298, City House, London Road, Croydon. However, although this lamp holder dispenses with the need for a screw driver to make the connections, it is still necessary to strip the insulator from a sheathed conductor and the installer must still know what connections to make.

According to a first aspect of the present invention there is provided a lamp holder for connecting a lamp in series in a lighting circuit, comprising a mounting member, means for guiding a current conductor from outside the lamp holder across the mounting member, a socket member for receiving a lamp, which socket member can be fastened to the mounting member, and means for locating the socket member in a predetermined orientation with respect of the mounting member, wherein the socket member comprises a pair of protruding conductive terminals and an insulating projection disposed such that when the socket member is located in said predetermined orientation and the current conductor is present across the mounting member the conductive terminals and the insulating projection register with the current conductor, the conductive terminals and the insulating projection being adapted such that when the socket member is offered up to the mounting member in the predetermined orientation, the terminals connect electrically with the current conductor and the insulating projection severs the current conductor between the terminals.

A lamp holder in accordance with the invention has an inherent direct-connecting facility whereby electrical connection to the current conductor becomes effective automatically during installation. This is advantageous because the lamp holder can easily be installed without knowing what connections have to be made. A further advantage is that no tools are needed to make the electrical connections.

Consequently, installing the lamp holder in a lighting circuit is brought within the capability of even the most modestly accomplished handyman. As such this lamp holder is ideally suited for small-scale lighting installations in the home and office. In particular, it provides a simple and effective way of installing built-in lighting for kitchen, bedroom and office furniture whether before, during or after assembly.

For example, the lamp holder can be mounted on the underside of a wall-hung cupboard where a lighting installation may be desirable to provide local illumination for a counter or working area below.

For ease of installing the lamp holder it is preferable if the guiding means provide a straight passage for the current conductor across the mounting member. In this case the conductive terminals and the insulating projection of the socket member are arranged in a row. The guiding means suitably comprise a recess in the mounting member.

The versatility of the lamp holder is enhanced when the locating means provide two predetermined orientations for the socket member with respect to the mounting member. To this end the socket member comprises two pairs of protruding conductive terminals and two insulating projections disposed and adapted such that when the socket member is offered up to the mounting member in one orientation, one pair of the terminals connect electrically with the current conductor and one of the insulating projections severs the current conductor, the other pair of terminals and the other insulating projection being redundant, and when the socket member is offered up to the mounting member in the other orientation the other pair of terminals connect electrically with the current conductor and the other insulating projection severs the current conductor, the one pair of terminals and the one insulating projection being redundant. In a preferred arrangement, one pair of terminals and one insulating projection are in a first row and the other pair of terminals and the other insulating projection are in a second row transverse to said first row.

According to a second aspect of the present invention there is provided a lighting circuit for a series-connected lamp comprising a current conductor, and a lamp holder in accordance with the first aspect of the present invention. The current conductor may be present in an insulating sheath. In this case, the conductor terminals are adapted for locally displacing the insulating sheath so as to connect electrically with the current conductor.

Preferably the current conductor extends on a surface of an insulating ribbon having a uniform width, the current conductor being fixed at a uniform spacing from an edge of the ribbon. The use of such a ribbon has the advantage that it facilitates simple and effective installation and connection. Installation of the lighting circuit can further be simplified if the surface of the ribbon remote from the current conductor is self adhesive.

According to a further aspect of the invention there is provided a lighting system comprising first and second series connected lighting circuits having a respective first and second current conductor and a respective first and second lamp holder, the first lamp holder comprising a first mounting member, means for guiding at least the first current conductor from outside the first lamp holder across the first mounting member, a first socket member for receiving a lamp, which first socket member can be fastened to a first mounting member, and means for locating the first socket member in a predetermined orientation with respect to the first mounting member, wherein the first socket member comprises a first pair of protruding conductive terminals and a first insulating projection disposed such that when the first socket member is located in the predetermined orientation and the first current conductor is present across the first mounting member the first pair of conductive terminals and the first insulating projection register with the first current conductor, the first pair of conductive terminals and the first insulating projection being adapted such that when the first socket member is offered up to the first mounting member in the predetermined orientation the first pair of conductive terminals connect electrically with said first current conductor and the first insulating projection severs the first current conductor between the first terminals of the first pair, the second lamp holder comprising a second mounting member, means for guiding at least the second current conductor from outside the second lamp holder across the second mounting member, a second socket member for receiving a lamp, which second socket member can be fastened to the second mounting member, and means for locating the second socket member in a predetermined orientation with respect to the second mounting member, wherein the second socket member comprises a second pair of conductive terminals and a second insulating projection disposed such that when the second socket member is located in the predetermined orientation and the second current conductor is present across the second mounting member the second pair of conductive terminals and the second insulating projection register with the second current conductor, the second pair of conductive terminals and the second insulating projection being adapted such that when the second socket member is offered up to the second mounting member in the predetermined orientation the second pair of conductive terminals connect electrically with said second current conductor and the second insulating projection severs the second current conductor between the terminals of the second pair.

This lighting system comprises two separate circuits and has the advantage that one or more respective lamp holders can be connected into each circuit. To eliminate the risk of inadvertently connecting a lamp holder into the wrong circuit, the first and second socket members are preferably adapted to be fitted in mutually exclusive manner to the first and second mounting members respectively. As a visual aid to correct installation, the first socket member and the first mounting member may have a first identifying colour or mark, and the second socket member and the second mounting member may have a second identifying colour or mark, different to the first identifying colour or mark.

The lighting system with two circuits can be as straightforward to install as a single circuit when the first and second current conductors of the respective circuits are uniformly spaced and are fastened to a common insulating ribbon. To complete the two lighting circuits, a third current conductor common to both lighting circuits may also be fastened to the ribbon between the first and second current conductors and a connector unit electrically connects the first and second current conductors respectively to the third current conductor.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which Figures 1 a and 1 b are exploded perspective views showing respectively the socket member and the mounting member of a lamp holder in accordance with the invention, Figure 1 c is a perspective view of a ribbon cable for connecting the lamp holder in a series-connected circuit, Figure 1 d is an exploded perspective view of alternative components for a different lamp holder in accordance with the invention, and Figure 2 is a partly schematic and partly perspective view of a lighting system in accordance with the invention.

The socket member shown in Figure 1 a comprises a generally rectangular block 1 of insulating material such as, for example, polycarbonate, and has a socket 2 for receiving the end connector 3 of a push-fit lamp 4. The upper face of the block 1 is substantially square. The end connector 3 fits tightly into the socket 2. Two connection pins 5a, 5b protruding from the end connector 3 electrically contact terminals 6a, 6b respectively in socket 2 when the lamp 4 is inserted. As shown in part in Figure la, the lamp 4 is a single-ended miniature fluorescent lamp with an integral starter (not shown) enclosed within the end connector 3. A range of such lamps (designated PL7, PL9, PL1 1) is featured on pages 309-312 of the Philips Lighting Catalogue mentioned above.

The block 1 has four pairs of slots, 7a, 7b; 8a, 8b; 9a, 9b; 1 Oa, 1 Ob arranged syrmetrically in a cruciform configuration on its upper face. One slot 7a, 8a, 9a, 1 0a of each pair communicates with an internal conductor (not shown) which is connected electrically to the socket terminal 6a and the other slot 7b, 8b, 9b, 1 0b of each pair communicates with another internal conductor (not shown) which is connected electrically to the socket terminal 6b.

A rectangular frame 11 made, for example, of polycarbonate is fastened at the upper edge of the block 1 to provide an upstanding flange around its periphery. The frame 11 is fastened to the block with adhesive. Alternatively the frame 11 may be formed integ rally with the block 1. Internally, the frame 11 is the same size as the upper surface of the block 1.

Present on one side 1 a of the frame 11 is an outwardly extending protrusion 42 having a generally rectangular outline. A close-fitting rectangular plate 1 2 made of insulating material such as, for example, polycarbonate is seated within the upstanding flange presented by the frame 11. The thickness of plate 1 2 is such that its upper surface lies substantially flush with the upper edge of the frame 11.

The plate 1 2 has two pairs of mutually orthogonal rectangular slots 1 3a, 1 3b; 1 4a, 1 4b which register with the slots 7a, 7b; 8a, 8b respectively in the block 1 when the plate 1 2 is seated within the frame 11. The plate 1 2 is fastened flat against the upper surface of the block with adhesive.

Two pairs of conductive terminals 1 5a, 1 sub and 1 6a, 1 6b, made, for example of copper are inserted through the slots 1 3a, 1 3b; 1 4a, 14b in block 12 and into slots 7a, 7b; 8a, 8b such that terminals 1 spa, 1 6a connect electrically with socket terminal 6a and terminals 1 sub, 1 6b connect electrically with socket terminal 6b. The terminals 1 spa, 1 sub; 1 6a, 1 6b are held fast by mechanical engagement within the slots. Each terminal 1 5a, 1 sub; 1 6a, 1 6b is provided with a keyhole-shaped slot 1 7 at the end remote from plate 1 2.

When fully inserted the terminals 1 spa, 1 sub; 1 6a, 1 6b protrude above the upwardly-directed surface of the insulating plate 1 2.

An insulating projection 18, made of, for example, polycarbonate, is provided between the terminals 1 5a, 1 sub but offset from the mid-point. In the present embodiment the projection 1 8 is formed integrally with plate 1 2. However, it is noted here that it may alternatively be secured in appropriate slots provided in the plate 1 2 and possibly also in the block 1. The end of the insulating projection 18 remote from the plate 1 2 is chamfered to provide a sharp cutting edge 18a.

The terminals 15a, 15b and the insulating projection 1 8 lie in a first row. A similar chamfered insulating projection 1 9 is provided in a similar disposition relative to the terminals 1 6a and 16b, so that the terminals 16a, 1 6b and the insulating projection 1 9 lie in a second row orthogonal to the first row.

The insulating plate 1 2 additionally comprises four resilient hook-like projections 20 disposed respectively at each of the corners of the plate 1 2 on the upwardly directed surface.

The projections 20 are formed integrally with the plate 12.

The mounting member shown in Figure 1b comprises an annular base plate 21 having a generally square outline. Screw holes 25 disposed at two diametrically opposed corners are provided for fixing the base plate 21 to a mounting surface. A rectangular recess 22 is disposed centrally at the upper surface at each of two opposite walls of the base plate 21.

These recesses are for guiding a current conductor across the mounting member as described in more detail below. Two rectangular recesses 23a, 23b are disposed centrally at the internal surface of two adjacent walls respectively of the base plate 21. Two pairs of similar rectangular recesses 24a, 24b are disposed symmetrically at the internal surface of the two other walls of the base plate 21. The recesses 23a, 23b; 24a, 24b are provided for location purposes, as explained in more detail below.

The mounting member also comprises a generally rectangular frame 26, shaped and dimensioned so as to fit closely within the base plate 21. The frame 26 is secured in the base plate 21, for example, using adhesive.

On two adjacent walls the contour of the frame 26 complements the internal configuration of the base plate 21. The frame 26 thus has internal recesses 27a, 27b having a rectangular outline which co-operate with the recesses 23a, 23b in the base plate 21. The other two walls of the frame 26 are straight and therefore close off the recesses 24a, 24b in the base plate 21. The bottom edge of the frame 26 has an outwardly extending flange 28, which acts as a stop to prevent the frame 21 being inserted too far into the base plate 21. The frame 26 is shallower than the base plate 21, in order that it does not foul the recesses 22 in the base plate 21. The upper edge of the frame 26 has an inwardly extending flange 29, which acts as a stop to prevent the socket member being inserted too far into the mounting member when the lamp holder is assembled during installation.Apertures 30 are provided in the flange 29, one at each corner of the frame 26. The apertures are registered to co-operate with the hook-like projections 20 on the plate 1 2 of the socket member, thereby enabling the socket member to be snap-fastened to the mounting member.

A cable for connecting the lamp holder into a series-connected lighting circuit is shown in Figure 1 c. The cable comprises three equally spaced current conductors 31a, 31b, 31 c enclosed within a respective insulating sheath 32a, 32b, 32c. The sheaths 32a, 32b, 32c are fastened in a mutually parallel arrangement to one surface of an insulating ribbon 33. The ribbon may be made for example of polyvinylchloride. The conductors 31 a, 31 b, 31 c lie parallel to the edges of the ribbon.

The width of the ribbon 33 is substantially the same as the width of the recesses 22 in the base plate 21 of the mounting member. The upper surface of the ribbon 33 may be selfadhesive. Although not shown in the figure, a second insulating ribbon may also be included so that the conductors in their insulating sheaths are sandwiched between the two ribbons. In the present embodiment, the current conductor 31a is a live conductor for one circuit, while the conductor 31 c is a live conductor for a second circuit; the conductor 31b being a neutral conductor common to both circuits. A lighting system comprising two lighting circuits will be described later with reference to Figure 2.

To install the lamp holder in a lighting circuit the ribbon cable is first fastened to a mounting surface using the self-adhesive surface of the ribbon. It will be evident that additional or alternative fixing methods may equally well be employed for this purpose.

The mounting member is then fastened flush against the mounting surface such that the ribbon cable is accommodated in the recesses 22, whereby the current conductors 31a, 31 b, 31 c extend straight across the base plate 21. The mounting member is secured to the mounting surface with screws through the screw holes 25. The socket member is then offered up to the mounting member such that the protrusion 42 on frame 11 co-operates with one or other of the recesses 27a, 27b in the frame 26 of the mounting member. The recesses 27a, 27b thus afford two predetermined orthogonal orientations for the socket member.On offering the socket member up to the mounting member in the orientation shown in the Figures, the terminals 15a, 15b both connect electrically with the current conductor 31a, the tapered entrance of the keyhole-shaped slot 1 7 in the end of the terminals first acting to displace the insulating sheath 32a and the circular portion of the slot then acting to grip the conductor 31a thereby effecting good electrical connection. At the same time, the chamfered edge 1 8a of the insulating projection 1 8 severs the conductor 31a and the insulating sheath 32a between the terminals 15a, 15b. After severing the insulating projection 1 8 forms an insulating barrier between the severed parts of the conductor 31a.The socket member is now inserted fully into the frame 26 of the mounting member until it abuts the flange 29, at which point the hook-like projections 20 co-operate with the apertures 30 in the flange 26 to provide a snap-fastening. The socket member is thus secured to the mounting member and the lamp holder is automatically connected in series in the circuit. When the socket member is installed in the orientation shown in Figures 1 a and 1 b when terminals 16a, 1 6b and the insulating projection 1 9 are so disposed that they do not engage any of the current conductors, and in this sense they are redundant.In the alternative orthogonal orientation however, it is these terminals 16a, 1 6b which connect electrically with the conductor 31a, and the insulating projection 1 9 which severs the conductor, the terminals 15a, 15b and the projection 1 8 now being redundant.

Figure 1 d shows alternative components for a different lamp holder, which can be connected to the other live current conductor 32a of the same ribbon cable. It is noted that an identical socket block 1 and an identical mounting member base plate 21 are used in this case. However, the frame 111 of the socket member comprises two syrmetrically disposed protrusions 142 on one side. The insulating plate 11 2 may be physically the same component as the corresponding plate 12, but rotated in its own plane through 1800. The conductive terminals and insulating projections are included in a manner analagous to that already described, but now the terminals engage the slot 8a, 8b; 9a, 9b in the block which were previously redundant.

The frame 1 26 of the mounting member is similar to that described previously, except that on two adjacent walls it has a respective pair of internal recesses 127a, 1 27b complementing the recesses 24a, 24b in the base plate 21. The other two walls of the frame 1 26 are straight and therefore close off the recesses 23a, 23b in the base plate 21.

This lamp holder is assembled and installed in exactly the same way as the lamp holder already described. However, in this case, when the socket member is offered up to the mounting member in one orientation, one pair of conductive terminals connect electrically with the current conductor 31 c and the intermediate insulating projection severs conductor 31 c between the terminals, the other terminals and projection being redundant. In the alternative orientation it is the other terminals which make the connection and the other projection which severs the conductor 31 c.

The protrusions 42, 1 42 on the respective frames 11, 111 of the socket members and the complementary configuration of the mounting member frames 26, 1 26 ensure that a lamp holder intended for a particular circuit cannot inadvertently be connected into the wrong circuit. As a visual aid to simplify installation, different identifying colours or marks may be used for the component parts of the different lamp holders. For example, the socket member frame 11 and the mounting member frame 26 of the lamp holder intended for connection to the current conductor 31 a may be coloured red or marked '1' or 'A', while the equivalent frames 111, 1 26 of the lamp holder intended for connection to the current conductor 31 c may be coloured blue or marked '2' or 'B'.

The lighting system shown in Figure 2 employs the three core ribbon cable and one each of the two different lamp holders described above, with reference to Figures 1a-1d. The live conductor 31a of the ribbon cable is connected via a ballast B1 to the live terminal of an AC mains supply. The live conductor 31c is also connected via a similar ballast B2 to the live terminal of an AC mains supply. The neutral conductor 31 b is common to both circuits and is connected directly to the neutral terminal of the supply. An appropriate ballast is featured on page 311 of the aforementioned Philips Lighting Catalogue, and is designated BPL 10L 24. A lamp holder 70 is connected to the current conductor 31a in one circuit, and a lamp holder 72 is connected to the current conductor 31 c in the other circuit.The construction of the respective lamp holders 70, 72 is as described above with reference to Figures 1 a and 1 b, and Figure 1d. A miniature single-ended fluorescent lamp 71, 73 is included in the lamp holders 70, 72 respectively. The circuits are completed by an end connector 75 extending across the ribbon cable. The end conductor 75 has a recess 76 for accommodating the ribbon cable so that the end connector is mounted flush ag ainst the mounting surface.

Conductive terminals (not shown) within the end conductor 75 electrically connect the respective current conductors 31 a and 31 c to the common current conductor 31 b. The construction and operation of these terminals may be similar to that of the terminals employed for connecting the ribbon cable in the lamp holder as described above.

It will be evident to the person skilled in the art that many modifications may be made within the scope of the invention. For example, the individual circuits of the lighting system just described may comprise more than one lamp holder, and indeed, may even comprise more than two circuits. Moreover, the number of lamp holders may be different in each circuit. Furthermore, it is noted that the lamp holder need not provide two predetermined orientations for mounting the socket member with respect to the mounting member. When only one orientation is required, only one appropriate recess is provided in the frame and the base plate respectively of the mounting member. In this case too, only one pair of conductive terminals and only one insulating projection need be provided on the socket member. Finally, it is noted that the lamp holder in accordance with the inv ention may be used for connecting lamps other than miniature fluorescent lamps, for example conventional incandescent lamps.

Claims (21)

1. A lamp holder for connecting a lamp in series in a lighting circuit, comprising a mounting member, means for guiding a current conductor from outside the lamp holder across the mounting member, a socket member for receiving a lamp, which socket member can be fastened to the mounting member, and means for locating the socket member in a predetermined orientation with respect to the mounting member, wherein the socket member comprises a pair of protruding conductive terminals and an insulating projection disposed such that when the socket member is located in said predetermined orientation and the current conductor is present across the mounting member the conductive terminals and the insulating projection register with the current conductor, the conductive terminals and the insulating projection being adapted such that when the socket member is offered up to the mounting member in the predetermined orientation the terminals connect electrically with the current conductor and the insulating projection severs the current conductor between the terminals.

2. A lamp holder as claimed in Claim 1, wherein the conductive terminals and the insulating projection are in a row.

3. A lamp holder as claimed in Claim 1 or Claim 2, wherein the locating means provide two predetermined orientations for the socket member with respect to the mounting member, and the socket member comprises two pairs of protruding conductive terminals and two insulating projections disposed and adapted such that when the socket member is offered up to the mounting member in one orientation one pair of the terminals connect electrically with the current conductor and one of the insulating projections severs the current conductor, the other pair of terminals and the other insulating projection being redundant, and when the socket member is offered up to the mounting member in the other orientation the other pair of terminals connect electrically with the current conductor and the other insulating projection severs the current conductor, the one pair of terminals and the one insulating projection being redundant.

4. A lamp holder as claimed in Claim 3, wherein the one pair of terminals and the one insulating projection are in a first row and the other pair of terminals and the other insulating projection are in a second row transverse to said first row.

5. A lamp holder as claimed in any of the preceding claims, wherein the means for guiding the current conductor comprises a recess in the mounting member.

6. A lamp holder as claimed in any of the preceding claims, wherein the locating means comprise co-acting parts of the socket member and the mounting member respectively.

7. A lamp holder as claimed in any of the preceding claims, wherein the conductive terminals are adapted for positive engagement with the current conductor.

8. A lamp holder as claimed in any of the preceding claims, wherein the insulating projection has a chamfered edge for severing the current conductor.

9. A lamp holder as claimed in any of the preceding claims, wherein the socket member and the mounting member are adapted for snap-fit fastening.

10. A lamp holder for connecting a lamp in series in a lighting circuit substantially as herein described with reference to Figures 1 a and 1 b or 1 d of the accompanying drawings.

11. A lighting circuit for a series-connected lamp, comprising a current conductor, and a lamp holder as claimed in any of the preceding claims.

1 2. A lighting circuit as claimed in Claim 11, wherein the current conductor is present in an insulating sheath, and the conductive terminals are adapted for locally displacing the insulating sheath so as to connect electrically with the current conductor.

1 3. A lighting circuit as claimed in Claim 11 or Claim 12, wherein the current conductor extends on a surface of an insulating ribbon having a uniform width, the current conductor being fixed at a uniform spacing from an edge of the ribbon.

14. A lighting circuit as claimed in Claim 13, wherein the surface of the ribbon remote from the current conductor is self-adhesive.

15. A lighting system comprising first and second series connected lighting circuits having a respective first and second current conductor and a respective first and second lamp holder, the first lamp holder comprising a first mounting member, means for guiding at least the first current conductor from outside the first lamp holder across the first mounting member, a first socket member for receiving a lamp, which first socket member can be fastened to the first mounting member, and means for locating the first socket member in a predetermined orientation with respect to the first mounting member, wherein the first socket member comprises a first pair of protruding conductive terminals and a first insulating projection disposed such that when the first socket member is located in the predetermined orientation and the first current conductor is present across the first mounting member the first pair of conductive terminals and the first insulating projection register with the first current conductor, the first pair of conductive terminals and the first insulating projection being adapted such that when the first socket member is offered up to the first mounting member in the predetermined orientation the first pair of conductive terminals connect electrically with said first current conductor and the first insulating projection severs the first current conductor between the first terminals of the first pair, the second lamp holder comprising a second mounting member, means for guiding at least the second current conductor from outside the second lamp holder across the second mounting member, a second socket member for receiving a lamp, which second socket member can be fastened to the second mounting member, and means for locating the second socket member in a predetermined orientation with respect to the second mounting member, wherein the second socket member comprises a second pair of conductive terminals and a second insulating projection disposed such that when the second socket member is located in the predetermined orientation and the second current conductor is present across the second mounting member the second pair of conductive terminals and the second insulating projection register with the second current conductor, the second pair of conductive terminals and the second insulating projection being adapted such that when the second socket member is offered up to the second mounting member in the predetermined orientation the second pair of conductive terminals connect electrically with said second current conductor and the second insulating projection severs the second current conductor between the terminals of the second pair.

16. A lighting system as claimed in Claim 15, wherein the first and second socket members are adapted to be fitted in mutually exclusive manner to the first and second mounting members respectively.

1 7. A lighting system as claimed in Claim 1 5 or Claim 16, wherein the first socket member and the first mounting member have a first identifying colour or mark and the second socket member and the second mounting member have a second identifying colour or mark different to the first identifying colour or mark.

1 8. A lighting system as claimed in any of Claims 15 to 17, wherein the first and second current conductors are uniformly spaced and are fastened to a common insulating ribbon.

19. A lighting system as claimed in Claim 18, wherein a third current conductor common to said first and second circuits is fastened to the ribbon between the first and second current conductors.

20. A lighting system as claimed in Claim 19, wherein a connector unit electrically connects the first and second current conductors respectively to the third current conductor.

21. A lighting system substantially as herein described with reference to Figure 2 of the accompanying drawings.