GB2406445A

GB2406445A - Junction element

Info

Publication number: GB2406445A
Application number: GB0322169A
Authority: GB
Inventors: Ken Richardson
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-09-23
Filing date: 2003-09-23
Publication date: 2005-03-30
Also published as: GB0322169D0

Abstract

A junction element 40 for an electrical wiring system, comprising a circuit part 45 and a connection part 46,47,48,49 to connect a cable 41,42,43,44 having a plurality of cores 17,18,19 to the junction element. The connection part has a plurality of connectors, each connector being adapted to engage a corresponding core of the cable, each connector being appropriately connected to the circuit part.

Description

Title: Junction Element

Description of Invention

This invention relates to a junction element for an electrical wiring system, a wiring system comprising a junction element and a method of connecting a cable to a junction element.

In broad terms, electrical wiring systems comprise multi-core electrical cables connected between junctions referred to herein as junction elements.

Such junction elements may provide operative parts of the wiring system, such as switches, plugs, fuse boards or distribution boards or similar items. Equally, such junction elements may comprise junction boxes which serve to connect different cables and provide branches to the system as required. Such junction elements may comprise junction boxes generally, and specifically may include such fittings as ceiling roses for a lighting circuit.

In general, to connect a cable to a junction element, each core of the cable is connected to an appropriate terminal of the junction element. To do so, an outer sheath of the cable must be removed, and each core cut to the appropriate length and the end part stripped to connect it to the terminal. The terminals are often located such that each core must be cut to a different, appropriate length to allow the cable to be connected to the junction element.

A further problem is that known junction boxes often comprise generalpurpose junction boxes with a plurality of pins or connectors to which cores from different cables may be connected to provide the appropriate junction and circuit as desired. This requires a degree of expertise and knowledge to connect the cables to the junction box correctly, can be time consuming and may be connected in a manner according to the discretion of the individual installer or electrician, rather than being necessarily standardized.

An aim of the present invention is to reduce or overcome the above problems.

According to a first aspect of the invention we provide a junction element for an electrical wiring system, the junction element comprising a circuit part and a connection part to connect a cable having a plurality of cores to the junction element, the connection part having a plurality of connectors, each connector being adapted to engage a corresponding core of the cable, each connector being appropriately connected to the circuit part, the connectors being disposed such that the length of each core extending from the cable to the connector is of a generally pre defined length.

The junction element may comprise predefined lengths which are such that each core is a different length.

Alternatively, the predefined lengths may be such that the length of each core is approximately equal.

The circuit part may comprise a switch.

The junction element may comprise a plurality of connection parts to connect a plurality of cables to the junction element and wherein the circuit part comprises a plurality of links to connect the cores of the plurality otcables.

The circuit part may comprise a plurality of links to connect the cores of the plurality of cables in accordance with the desired function of the junction element.

The junction element may comprise a junction box for a switched system with an onward power connection having a first connection part for connection to a power in cable, a second connection part for connection to a power out cable, a third connection part for a connection to a switch cable and a fourth connection part for connection to a device output cable, wherein the circuit part connects a live connector of the first, second and third connection parts, an earth connector of the first, second, third and fourth connection parts, a neutral connector of the first, second and fourth connection parts, and a live connector of the fourth connection part to the neutral connector of the third connection part.

The junction element may comprise a junction box for a two-switch lighting system, the junction element farther comprising a fifth connection part for connection to a second switch cable, the circuit part connecting a live connector of the fifth connection part to a live connector of the first, second and third connection parts, an earth connector of the fifth connection part to the earth connector of the first, second, third and fourth connection parts, a live connector of the fourth connection part to a neutral connector of the fifth connection part, and a common connector of the fifth connection part to a common connector of the third connection part.

A junction element may comprise a connection part which is provided on a first section of the junction element and the circuit part is provided on a second section of the junction element which is removably connectable to the first section, such that each connector is connected to the circuit part when the second section is connected to the first section.

A junction element may comprise a plurality of contacts each connected to a connector of the connector part, wherein the circuit part engages the contacts when the second section is connected to the first section.

According to a second aspect of the invention we provide a wiring system comprising a junction element according to the first aspect of the invention, the junction element being connected to at least one cable having a plurality of cores, the length of the cores extending from the cable being of a generally predefined length.

The wiring system may comprise a plurality of junction elements interconnected by at least one cable having a plurality of cores, wherein the cores extending from the cable at each junction element are each of a generally predefined length.

The predefined length of a core may correspond to the polarity or electrical connection corresponding to that core.

According to a third aspect of the invention we provide a method of connecting a cable to a junction element comprising the steps of removing an end part of a sheath of the cable to expose the cores, cutting each of the cores to a generally predefined length for that core and engaging the cores with a connection part of the junction box.

The present invention thus provides consistent connection parts across all junction elements used in a system, thus removing the need to trim individual cores to different lengths. By providing pre-wired circuits, the need to wire individual junction boxes according to the intended use is removed and the installation time is similarly reduced.

The present invention will now be described by way of example only with reference to the accompanying drawings, wherein, FIGURE 1 is a diagrammatic illustration of a junction element comprising a switch embodying the present invention; FIGURE 2 is a diagrammatic illustration of a junction element comprising a further switch embodying the present invention, FIGURE 3 is a diagrammatic illustration of a junction element comprising a junction for a switched circuit embodying the present invention, FIGURE 4_ is a diagrammatic illustration of a first part of a further junction box embodying the present invention, FIGURE 4b is a diagrammatic illustration of a second part of a junction box embodying the present invention, FIGURE 5 is a diagrammatic illustration of a part of a two-switch circuit FIGURE 6 is a diagrammatic illustration of a junction box for the circuit of Figure S. and FIGURE 7 is a diagrammatic illustration of a farther connection part.

Referring now to Figure 1, a junction element 10 is shown in this example comprising a switch and particularly a light switch. The switch 10 comprises a connection part 11 and a circuit part generally illustrated at 12, in S this example providing the switch 12a. The connection part l l comprises a plurality of connectors 13, 14, 15, each of which is connected to the circuit part 12 as appropriate. The junction element 10 is connected to a cable 16, which has a plurality of cores 17, 18, 19 held within an outer sheath 20. Each core 17, 18, 19 emerges beyond the end of the sheath 20 and is connected to a corresponding connector 13, 14, 15 on the connection part 11. Each core 17, 18, 19 extends from the sheath 20 by a predefined length which in this example is approximately equal. The connection 11 may use any appropriate connection method as desired; for example, it may comprise a sleeve and a screw into which a stripped end of the respective core is received, or a clip or any other type of connector as required.

In the alternative of Figure 2, a junction element 21 comprising a switch is shown comprising a first section 22 and a second section 23. In this version, the connection element shown at 24 is provided on the first section 22, which may, for example, be a back plate of the junction element 21. The connection part 24 comprises a plurality of connectors 25, 26, 27, in like manner to the connectors 17, 18, 19 of the embodiment of Figure 1, to which respective cores, 17, 18, 19 of a cable 16 are connected. In like manner to Figure 1, each of the cores 17, 18, 19 extends from the cable 16 in this example by approximately the same length. In this embodiment, however, each connector 25, 26, 27 is connected to a corresponding contact 28, 29, 30. The circuit part 31 is provided on the second section 23 and is provided with farther contacts 32, 33, 34.

When the second section 23 is fitted to the first section 22, the further contacts 32, 33, 34 engage the corresponding contacts 28, 29, 30, connecting the circuit part 31 to the connection part 24. The first part 22 and second part 23 may be connected, for example, by screws passing through screw holes generally shown at 35.

This embodiment is particularly advantageous in that the cable is clamped in place by a cable clamp 36, and there is no stress on the cable, the cores 17, 18, 19 or the connectors 24 as a result of the first section 23 being unscrewed or removed. No wiring is needed to change or replace the switch 31a since a replacement second section 23 can simply be attached to the first section 22.

Referring now to Figure 3, a junction box for a switched circuit, for example a lighting circuit, is generally shown at 40. In conventional manner, the junction box is connected to a first cable 41 which is a power-in cable, a second cable 42 to provide a power-out cable, a third cable 43 which is connected to a switch, such as the switch of Figure 1 or Figure 2, or a conventional switch as required, and a fourth, device output, cable 44 leading to, in this example, a light fitting. Each cable 41, 42, 43, 44 is a cable having a plurality of cores, in this case three, of conventional type, similar to that shown in Figures 1 and 2. The cores of the various cables must be connected in a particular manner, as follows, the live cores of the first, second and third cables_ must be connected, the cores connected to earth of all four cables 41, 42, 43, 44 must be connected, the neutral cores of the first cable 41, second cable 42 and fourth cable 44 must be connected and the live cable of fourth cable 44 must be connected to the neutral core of the third cable 43. Conventionally, the connection is performed by joining the respective cores at different connection points on a general purpose junction box, requiring that the cores be cut to varying lengths and a certain amount of skilled knowledge on the part of the electrician to ensure that the junction is correctly wired. In the present example, the junction box 40 of Figure 3 is provided with a circuit part 45 and four connection parts 46, 47, 48, 49 corresponding to the first cable 41, second cable 42, third cable 43 and fourth cable 44 respectively. In like manner to the connection parts 13, 24 of Figures 1 and 2, each connection part 46, 47, 48, 49 has three connectors in like manner to the connectors 13, 14, 15 of Figures 1 and 2, each connector corresponding to a particular core 17, 18, 19 of the cable to which it is to be attached. In this example, the connectors for connection to the live core of the corresponding cable are shown at 46a, 47_, 48_ and 49a.

The connectors for connection to the earth core of the corresponding cable are shown at 46_, 47_, 48b and 49b. The connectors for connection to the neutral core of the corresponding cable are shown at 46c, 47, 48_, and 49_.

The circuit part 45 is shown with a plurality of circuit tracks generally lO shown at 50 which are interconnected at points generally illustrated at 51. As will be clear, the tracks 50 are arranged to connect connectors 46a, 47a and 48_, 46b,47b, 48b and 49_, 46c, 47_ and 49_, and to connect 48_ to 49a.

Hence, when it is desired to install a junction box, all that is necessary is that each core 17, 18, 19 of respective cables 41, 42, 43, 44 is cut to, in this example, approximately the same length, the ends of the cores are prepared, if necessary, and then each core 17, 18, 19 is attached to the corresponding connector of the appropriate connection part 46, 47, 48, 49. The reduces the time required to provide Haywire the junction and reduces the degree of knowledge required to correctly wire the junction element 40.

A further lighting circuit 55 is shown at Figure 5. The circuit is of the type in which two light switches 56, 57 may be operable to switch on and off a light shown at 58, where the light may toggled on and off from either switch 56, 57. A junction element comprising a junction box 60 embodying the present invention is shown connected to a first cable 61 comprising a power-in cable, a second cable 62 comprising a power-out cable, a third cable 63 leading to the switch 56, a fourth cable 64 leading to the lamp 58 and a fifth cable 65 leading to switch 57. In like manner to the junction box 43, the junction box comprises a plurality of connection parts 66, 67, 68, 69 and 70, corresponding to the first cable 61, second cable 62, third cable 63, fourth cable 64 and fifth cable 65 respectively. The junction box 60 has a circuit part 71 which is similar to the circuit part 45 of Figure 3. To provide the two-switch configuration however, the fifth connection part 70 is provided having four connectors 70_, 70_, 70_, and 70_. The connection part 68 for connection to a third cable 63 also has four connectors 68a, 68b, 68_, 68_. In like manner to the connectors 46, 47, 48 of Figure 3, the connectors 66, 67, 69 have three connectors, connectors 66_, 67_, and 69a for connection to a live core of each cable 61, 62, 64, a connector 66_, 67b, 69_ for connection to a earth core of each cable, and a connector 66_, 67_, 69 for connection to a neutral core of the respective cable 61, 62, 64. The circuit part 71 is provided with tracks 72 connected at connection points 73. The circuit part 71 connects the connectors 66b, 67_, 68b, 69b, 70_ to connect the respective earth core of each cable 61, 62, 63, 64, 65. The circuit 71 also connects connectors 66a, 67a, 68_, 70a to connect the live core of each of the cables 61, 62, 63, 65. The circuit 71 connects the connectors 66c, 67_, 69_ corresponding the neutral cores of cables 61, 62, 64. The connectors 70_, 68_ are connected to what may be described as the neutral core of the cable 63, 65, or alternatively the second live core, and are connected by track to the connectors 69_ corresponding to the live core of the cable 64 leading to the lamp. The circuit part 71 further links connectors 68_, 70_ which links a fourth core of each cable 63, 65, referred to as a "common" connection to connect light switches 56, 57 in standard manner to provide a two-switch circuit. As might be expected, to wire such a circuit in a general-purpose junction box is even more complicated than the junction box of Figure 3, whilst to connect the junction box of Figure 6 it is simply necessary to prepare each cable such that each core 17, 18, 19, 73 is approximately the same length, and engage the end part of each core with the respective connector of the connection part 66, 67, 68, 69, 70.

With reference to Figures 4_ and 4b, a further embodiment of the junction box of Figure 3 is shown in which the junction element, generally illustrated at 45, has a first section 80 and a second section 81. The circuit part, generally illustrated at 45' is provided on the second section 81. Each cable 41, 42, 43 is connected to a corresponding connection part 46, 47, 48, 49 as can be seen in Figure 3, but in this example, each connector of the connection parts 46, 47, 48, 49 are each connected to a respective one of a group of contacts generally shown at 82. The second section 81 is releasably connectable to the first section 80 by the appropriate means, such as by screws or a snap-fit or otherwise, such that when the second section 81 is attached to the first section 80, an appropriate part of the circuit part 45' engages each of the groups of contacts 82, to establish the appropriate connection between each connection part 46, 47, 48, 49 and the circuit parts 45'. The circuit parts 45' otherwise has the same set of tracks 50 and connection 51 as shown in Figure 3.

In the present invention, it will be apparent that each junction element of a wiring system, such as shown in Figure 5 may be in accordance with the present invention such that the end part of each connecting cable is prepared in the same, standardized, manner with each core projecting from each end of each cable compared to approximately the same length. It is envisaged that a standardised tool to be used which cuts and, possibly, strips each core to the appropriate length, thus reducing the time required to prepare the components for the wiring system and connect them. The tool may consist, for example, of two sets of shaped jaws and one blade. The first step would be to clamp the tool to the cable and cut the cable to length using the blade. A first set of the jaws would cut through the sheath. The second set of jaws, closest to the end of the cable, would cut through the individual sheaths of each core. By withdrawing the cable from the tool, the appropriate lengths of core cut to length would be exposed, leaving an appropriate length of bare wire to go into the respective connector of the connection part. Thus, by a single action, the end of a cable could be prepared for connection to a junction element. To prepare different cable types, it may envisaged that different, appropriately sized tools are used or that replaceable jaws could be provided on each tool to adapt to the required cable size.

Although for simplicity, in Figures I to 6 herebefore, each of the connection parts of each connector has been shown a line to such that each core of the cable is cut to the same length, it may alternatively be desirable for the cores to be cut generally to predefined different lengths. The reason for doing so is that each core may have a different predefined length depending on the polarity of intended connection of the core. By introducing such an asymmetry, the possibility of wiring the wrong core to the wrong connector may be reduced. For example, in Figure 7 a connection part is shown at 90 having connectors 90a, 90b, 90_ and a cable is shown at 91 held in place by a cable plant 92. Cores 93, 94, 95 extend from the cable 91 and are received in the corresponding connector 90_, 90_, 90_. It will be apparent that, where, for example, connection 90a corresponds to a live connection and connection 90_ to the neutral connection, if the corresponding cores are the appropriate length it is rendered more difficult wrongly to connect the cores.

To prepare the cable, a tool as discussed above may be provided, but with the jaws and blade suitably inclined or staggered or otherwise to ensure that each core is cut to the correct length.

It will be apparent, that in accordance with the present invention, some or all of the junction elements of a system may be provided with connection parts such that each junction element has a similar or identical connection part to the other junction elements and so the requirement to prepare each cable by cutting and stripping the cores to the appropriate length is standardised across the wiring network.

Although the present examples have related to switches and junction boxes for electrical lighting systems, it might be envisaged that the invention could be applied to any appropriate junction element for any electrical wiring system, such as sockets, plugs, junction boxes, fuse boards or distribution panels, or any appropriate product. The circuit part may provide such connections or functional parts as is necessary to provide the junction element with the desired function. The separation of the connection part and circuit part onto a first section and second section of a junction element may be applied to any junction element where appropriate and it will be apparent that the invention may be applied to any system having cables having any number of cores, or indeed separate cables where appropriate.

In the present specification "comprises" means "includes or consists of" and "comprising" means "including or consisting of".

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A junction element for an electrical wiring system, the junction element comprising a circuit part and a connection part to connect a cable having a plurality of cores to the junction element, the connection part having a plurality of connectors, each connector being adapted to engage a corresponding core of the cable, each connector being appropriately connected to the circuit part, the connectors being disposed such that the length of each core extending from the cable to the connector is of a generally pre defined length.

2. A junction element according to the claim 1 wherein the predefined lengths are such that each core is a different length.

3. A junction element according to claim 1 wherein the predestined lengths are such that the length of each core is approximately equal.

4. A junction element according to any one of claims 1 to 3 wherein the circuit part comprises a switch.

5. A junction element according to any one of claims 1 to 3 wherein the junction element comprises a plurality of connection parts to connect a plurality of cables to the junction element and wherein the circuit part comprises a plurality of links to connect the cores of the plurality of cables.

6. A junction element according to claim 5 wherein the circuit part comprises a plurality of links to connect the cores of the plurality of cables in accordance with the desired function of the junction element.

7. A junction element according to claim 6 wherein the junction element comprises a junction box having a first connection part for connection to a power in cable, a second connection part for connection to a power out cable, a third connection part for a connection to a switch cable and a fourth connection part for connection to a device output cable, wherein the circuit part connects a live connector of the first, second and third connection parts, an earth connector of the first, second, third and fourth connection parts, a neutral connector of the first, second and fourth connection parts, and a live connector of the fourth connection part to the neutral connector of the third connection part.

8. A junction element according to claim 6 wherein the junction element comprises a junction box for a two-switch lighting system, the junction element further comprising a fifth connection part_for connection to a second switch cable, the circuit part connecting a live connector of the fifth connection part to a live connector of the first, second and third connection parts, an earth connector of the fifth connection part to the, earth connector of the first, second, third and fourth connection parts, a live connector of the fourth connection part to a neutral connector of the fifth connection part, and a common connector of the fifth connection part to a common connector of the third connection part.

9. A junction element according to any one of the preceding claims wherein the connection part is provided -on a first section of the junction element and the circuit part is provided on a second section of the junction element which is removably connectable to the first section, such that each connector is connected to the circuit part when the second section is connected to the first section.

10. A junction element according to claim 9 comprising a plurality of contacts each connected to a connector of the connector part, wherein the circuit part engages the contacts when the second section is connected to the first section.

11. A junction element substantially as described herein and/or as shown in the accompanying drawings.

12. A wiring system comprising a junction element according to any one of the preceding claims, the junction element being connected to at least one cable having a plurality of cores, the length of the cores extending from the cable being of a generally predefined length.

13. A wiring system according to claim 10 comprising a plurality of junction elements interconnected by at least one cable having a plurality of cores, wherein the cores extending from the cable at each junction element are each of a generally predefined length.

14. A wiring system according to claim 12 or claim 13 wherein the predefined length of a core corresponds to the polarity or electrical connection corresponding to that core.

15. A wiring system substantially as described herein and/ or as shown in the accompanying drawings.

16. A method of connecting a cable to a junction element according to any one of claims 1 to 11 comprising the steps of removing an end part of a sheath of the cable to expose the cores, cutting each of the cores to a generally predefined length for that core and engaging the cores with a connection part of the junction box.

17. Any novel feature or combination of features disclosed herein and/or in the accompanying drawings.