GB2441839A

GB2441839A - Mounting box for trunking having pluggable connector

Info

Publication number: GB2441839A
Application number: GB0709793A
Authority: GB
Inventors: Keith Wray Ball
Original assignee: Schneider Electric Ltd
Current assignee: Schneider Electric Ltd
Priority date: 2006-12-22
Filing date: 2007-05-22
Publication date: 2008-03-19
Anticipated expiration: 2027-05-22
Also published as: GB0709793D0; GB2441839B

Abstract

A mounting box for an electrical wiring accessory 12, such as a power socket, is adapted for mounting in a length of electrical trunking. The mounting box has an open front with walls at the back, top and bottom sides and left and right end faces, and is provided on at least one end face with a pluggable connector 14 for receiving a compatible supply wiring connector (18, Fig 4a) within the trunking to supply the accessory. The connector may be substantially within the mounting box, to reduce the space used up in the trunking, and the accessory may be prewired to the mounting box and tested at the factory so that it can be installed without requiring an electrician.

Description

2441839

1

Mounting box for electrical wiring accessories, assemblies and methods of installation thereof

The present invention relates to a mounting box for electrical wiring 5 accessories, particularly, but not exclusively, to a mounting box for electrical wiring accessories for use in electrical trunking. The invention further relates to assemblies and installations of such accessories and mounting boxes and methods of installation thereof

10 Electrical trunking is used as a housing for, amongst other things, electrical power cables within institutional, commercial or industrial properties. The trunking typically provides one or more channel portions which are typically plastic extrusions mounted to a wall. The power cables are housed within the channels and the channels are covered with a 15 number of cover portions. The covers are detachably mountable to the channel portions to allow access to the power cables.

Typically, a number of electrical accessories, such as power sockets, circuit breakers, light switches and the like, are installed at various 20 locations along the trunking. The electrical accessories are mounted to mounting boxes which are located within the channel portions of the trunking. Electrical power is delivered to the electrical accessory by wiring the power cables to the electrical accessory. The cover portions are cut to define an open portion of channel to accommodate the accessory.

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An electrical accessory is typically installed by mounting the mounting box within the channel portion, wiring the power cables to the electrical accessory via apertures in the mounting box and then attaching the electrical accessory to the mounting box. The mounting box may be a

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snap-fit within the channel, while the accessory is secured by two or more screws so that its face plate closes the box.

Mounting electrical accessories in this manner is time consuming, since it 5 requires the power cables to be wired to the accessory. It also requires the person mounting the accessory to have a certain level of training in view of the inherent danger in dealing with electrical power.

Pluggable wiring solutions to this are becoming widespread in building 10 installation generally, but known solutions rely on the availability of space beside and/or behind the mounting box, which limits their acceptance in trunking situations.

It is an object of the present invention to provide a pluggable mounting 15 system for electrical wiring accessories which is better adapted for use in conventional trunking.

According to a first aspect of the present invention, there is provided a mounting box for an electrical wiring accessory, the mounting box being 20 adapted for mounting in a length of electrical trunking, the mounting box having an open front with walls at the back, top and bottom sides and left and right end faces, wherein the mounting box is provided on at least one end face with a pluggable connector for receiving a compatible supply wiring connector within the trunking, the pluggable connector being 25 adapted to deliver electrical power from the supply wiring connector to an electrical wring accessory.

The accessory and mounting box can then be pre-assembled and tested at a factory location, and installed easily by plugged connections on site.

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3

Preferably, the pluggable connector is mounted in an aperture of the end face of the mounting box. This avoids increasing the depth of channel necessary for mounting.

5 Preferably, the aperture is formed from knock-out portions in the end face. The same mouldings can then be used for plugged and non-plugged installations.

For one popular type of connector (Wieland GST18i3), the aperture should 10 be substantially 33mm by 15.6mm.

Preferably, the pluggable connector is enclosed substantially within the mounting box. The length of trunking occupied is thereby not increased compared with conventional solutions.

15

Preferably, the pluggable connector is substantially flush with the end face of the mounting box.

Preferably, the pluggable connector includes attachment means for 20 attaching the connector within the aperture.

Preferably, the attachment means comprises projections for snap-fitting into the aperture.

25 Preferably, the mounting box includes attachment means for attaching the mounting box within the trunking.

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Preferably, the attachment means comprises projections for snap-fitting into the trunking.

4

In a preferred embodiment, a first type of projections are located on the left and right end faces of the mounting box (viewed as installed in a horizontal run of trunking).

5 The first projections may be positioned towards but slightly spaced from the open front of the mounting box for engaging the rear face of a cover portion at each end of the box.

In UK, for example, standard BS 4662:1970 and successor standards may 10 be applied, the mounting box being of size UA1 (unit square), US2 (double outlet), or US3 (triple outlet). The dimension between top and bottom side walls in that case will be approximately 75mm and the length between end walls approximately 75mm, 135mm or 195mm respectively.

15 Alternatively or, preferably, in addition, a second type of a second type of projections are located on the top and bottom walls of the mounting box for engaging complementary formations in side walls of said trunking.

In a preferred embodiment having both types of projections, the second 20 type of projections are positioned towards the back of the mounting box, compared with the first type. The exact position will be selected for compatibility with a particular form of trunking.

Preferably, the walls and sides of the mounting box are rectangular.

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Preferably, the mounting box has dimensions which conform to standards applicable in the territory. Flange portions may be provided along top and bottom edges of the mounting box open front, so as to be flush with the cover portions at the ends.

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5

Preferably, the mounting box includes threaded bosses for attaching a conventional electrical accessory thereto.

Preferably, the mounting box includes a pluggable connector on each end 5 face. This allows electrical continuity to be achieved along the trunking in minimum channel depth.

According to a second aspect of the present invention, there is provided an assembly for mounting in electrical trunking, the assembly comprising 10 and electrical wiring accessory assembled together with a mounting box according to the first aspect, wherein a face plate of the accessory closes the open front of the mounting box and wherein the pluggable connector is pre-wired together within the assembly to deliver electrical power from the supply wiring connector to the accessory without disassembly of the 15 accessory from the mounting box.

Preferably, the area of the face plate of the accessory is larger than the area of the open front of the mounting box.

20 Where the mounting box includes projections of the first type, a gap is then formed between those projections and the mounting box and the underside of the face plate of the accessory. The gap can receive the trunking cover portions in the finished installation.

25 The mounting box may further be provided with flange portions extending along top and bottom sides abutting the face plate of the accessory, at a depth corresponding to said gap at the end walls.

6

Preferably, the pluggable connector does not protrude through the aperture further than the distance the face plate extends over front of the mounting box.

5 Preferably, the projections do not extend further than the distance the face plate extends over front of the mounting box.

According to a third aspect of the present invention there is provided an electrical installation comprising:

10 at least one section of electrical trunking mounted within a building;

and at least one assembly according to the second aspect mounted within the trunking.

15 Preferably, the installation comprises a plurality of assemblies.

According to a fourth aspect of the present invention there is provided a method of installing a mounting box in a section of electrical trunking comprising the steps of:

20 providing a mounting box having an open front with walls at the back, top and bottom sides and left and right end faces;

providing at least one end face of the mounting box with a pluggable connector for receiving a compatible supply wiring connector; attaching the mounting box within the section of trunking; and 25 plugging the supply wiring connector into the pluggable connector.

In one preferred installation, electrical continuity between sections of supply wiring is provided through plugged connections at both ends of the mounting box. This reduces space requirement, by eliminating the need 30 for a cable running alongside or behind the mounting box.

Preferably, the method further comprises the preliminary step of wiring an electrical accessory to the pluggable connector and attaching the electrical accessory to the mounting box before the mounting box is attached within the trunking.

The preliminary step can be performed at a factory location remote from the installation site.

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BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

5

Figure 1 is a perspective view of a section of a known electrical trunking system;

Figure 2 is a perspective view of a known mounting box and electrical 10 accessory adapted for use with the trunking of Figure 1;

Figs. 3a and 3b are perspective views of a mounting box for an electrical wiring accessory according to the present invention;

15 Figure 3c is an end view of the assembled mounting box and electrical accessory of Figs. 3a and 3b mounted in electrical trunking with the trunking shown in cross-section;

Figure 3d is a side view of the assembled mounting box and electrical 20 accessory of Figure 3c; and

Figs. 4a and 4b are rear and front perspective views of the mounting box of Figs. 3a and 3b illustrated with supply wiring connectors, prior to final assembly.

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DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Figure 1 illustrates a known form of electrical trunking 1 which is made from plastic extrusions. A base 2 defining one or more channels 3 for 5 electrical power cables is mounted to a wall. A main cover portion 4 can be cut so as to define openings in which mounting boxes to receive electrical accessories can be installed within the channel..

Figure 2 illustrates a typical mounting box 5 and electrical accessory 6.

10 The mounting box 5 is attached within the trunking 1. The electrical power cables are then fed through the back wall of the mounting box 5 and then wired to the electrical accessory 6. The electrical accessory 6 is then attached to the mounting box 5.

15 The known mounting box 5 has knock-out portions around its periphery, which can be removed in a configuration appropriate for wires to lead from terminals at the back of the accessory in one or both directions along the conduit. For pluggable wiring systems, these wires may be short and provided with pluggable connectors such as from the Wieland gesis range.

20 (See http://www.wieland-electric.de/gesis_CON.51-0.html ). Space may be very tight in the trunking. If known pluggable wiring systems are used it will often be necessary to increase the size of the trunking system in one or more dimensions, or increase spacing between accessories, which reduces functionality, which increases cost.

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Figures 3a to 3d illustrate a modified mounting box 10 for an electrical accessory 12. The accessory 12 is a standard component. The mounting box 10 has an open front 10a with walls 10b, 10c, 10d, 10e, 10f at the back, top and bottom sides and left and right end faces, viewed as

30 mounted in use. Width of the box (outside top to bottom walls) is typically

10

75mm (BS 4662:1970). Dimensions of length vary according to the accessory wanted. A single unit (socket or switch) will have width 75mm, double 135mm and triple 195mm. Other sizes are of course possible, according to local conventions or special applications. Depth may be 5 25mm, 35mm or 50mm. for example.

The mounting box 10 has a pluggable connector 14 on the left end face 10e and on the right end face 10f. Each pluggable connector 14 is wired to the electrical wiring accessory 12 and is adapted to receive a 10 compatible supply wiring connector 18 (see figure 4a). Each pluggable connector 14 is therefore adapted to deliver electrical power from the supply wiring connector 18 to the electrical wiring accessory 12. Although the mounting box 10 has been illustrated in figures 3a to 3d as comprising two pluggable connectors 14, it should be appreciated that the mounting 15 box 10 may comprise only a single pluggable connector 14.

The mounting box 10 is adapted from a standard mounting box to include apertures 20 in each left and right end face 10e, 10f. The pluggable connectors 14 are mounted in the apertures 20. The aperture 20 may be 20 formed by creating knock-out portions in the left and right end faces 10e, 10f. Each pluggable connector 14 is therefore substantially enclosed within the mounting box 10.

The apertures 20 are dimensioned to receive push-fit pluggable 25 connectors, such as Wieland Gesis con GST 18i3 series. The dimension in that case is substantially 33mm by 15.6mm.

The connection port 14a of each pluggable connector 14 is substantially flush with the respective left and right end faces 10e and 10f. A flange

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projects a millimetre or two, but the whole assembly fits within the length of the accessory face plate.

Each pluggable connector 14 also includes attachment means (not 5 referenced) for attaching the connector 14 within the aperture 20. The attachment means may comprise projections which allow the connector 14 to be snap-fitted to the left and right end faces 10e, 10f. In this case the pluggable connector 14 may protrude through the aperture 20 slightly. However, the connector 14 will still remain substantially flush with the end 10 face 10e, 10f.

As best illustrated in figures 3a to 3c, the mounting box 10 also includes attachment means 22 for attaching the mounting box 10 within electrical trunking 24. The attachment means 22 are in the form of projections 15 which are located on the left and right end faces 10e, 10f and top and bottom walls 10c, and 10d of the mounting box 10. The projections 22 are configured to allow the mounting box 10 to be snap-fitted into the trunking 24.

20 As illustrated in figure 3a, the projections 22 on the left and right end faces 10e, 10f are positioned towards, but spaced from the open front 10a of the box 10, and the projections 22 on the top and bottom walls 10c, 10d are positioned further back, to engage complementary shoulders 25 within the side walls of the trunking channel. Flanges 23 run along the top and 25 bottom edges of the opening 10. However, it should be appreciated that the projections 22 may be positioned in any suitable position on the left and right end faces 10e, 10f or top and bottom walls 10c, 10d such that the mounting box 10 may be fitting into a particular type of trunking 24, as illustrated in figures 3c and 3d.

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12

It should also be appreciated that the mounting box 10 in a different embodiment may comprise projections 22 only on the left and right end faces 10e, 10f, or only on the top and bottom walls 10c, 10d. The embodiment illustrated follows conventional mechanical design for robust 5 compatibility with existing trunking.

With reference to figure 3a, the combined mounting box 10 and electrical accessory 12 constitute an assembly for mounting in electrical trunking. The assembly is formed by firstly attaching the pluggable connectors 14 to 10 the mounting box 10, as described above. The pluggable connectors 14 are then wired to the electrical accessory 12. Once the pluggable connectors 14 are wired to the electrical accessory 12, the electrical accessory 12 is then attached to the mounting box 10. This is effected by two screws 26 which are screwed through the electrical accessory 12 and 15 into two threaded bosses 28 in the mounting box 10. These bosses may be shortened compared with conventional boxes, to avoid interfering with the connectors 14. It should be appreciated that other suitable means for attaching the accessory 12 to the box 10 may also be used. The face plate 12a of the electrical accessory 12 therefore closes the open front 20 10a of the box 10.

Once the electrical accessory 12 has been attached to the mounting box 10, the assembly may be mounted in the trunking 24.

25 As illustrated in figures 3b to 3d, the area of the face plate 12a of the accessory 12 is larger than the area of the open front 10a of the mounting box 10. This produces in the finished assembly a circumferential abutment 30 between the walls 10b, 10c and faces 10e, 10f of the box 10 (including flanges 23) and the underside of the face plate 12a of the 30 accessory 12. Therefore, when the assembly is fitted into the trunking 24,

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the underside of the face plate 12 abuts against the cover portion 24a of the trunking 24.

The projections 22 allow the box 10 to be snap-fitted into the trunking 24. 5 The projections 22 abut against corresponding projections 24b in the trunking 24.

Furthermore, as illustrated in figure 3d, the cover portion 24a may also abut against the left and right end faces 10e, 10f, sandwiched between the 10 projections 22 and the abutment 30. Flanges 23 make up the thickness of the cover, where it is interrupted for the length of the accessory (Figure 3c).

As illustrated in figures 3b and 3c, the pluggable connectors 14 do not 15 protrude through the aperture 20 further than the distance that the face plate 12a extends over the front 10a of the mounting box 10. Also, the projections 22 do not extend further than the distance the face plate 12a extends over the front of the mounting box 10. Therefore, the pluggable connectors 14 and the projections 22 are within the downward projected 20 surface area of the face plate 12a.

Once the assembly has been fitted into the open trunking 24 it is necessary to connect the assembly with the supply wiring connector 18 in the trunking 24. As illustrated in figures 4a and 4b, the supply wiring 25 connector 18 is simply plugged into the pluggable connector 14. Cover portions 24a are then fitted to close the trunking either side of the accessory.

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The novel mounting box 10 thus enables the provision of pluggable wiring directly into electric mounting boxes intended for use with electrical trunking.

5 As the power cables in the trunking do not have to be wired to the electrical accessory 12 when installing the assembly, but are simply plugged into the pluggable connector 14, the installation of the assembly is simplified.

10 Furthermore, as the electrical accessory 12 is pre-wired to the mounting box 10, there is no need for the assembly to be fitted to the trunking 24 by highly qualified persons, as the assembly is snap-fitted into the trunking 24 and plugged into the power supply. Also, the assembly can be pre-tested during manufacture, which increases the speed of installation, as the 15 installer does not need to test any internal connections once installed.

Given a stock of these mounting boxes 10, a contractor or supplier can readily pre-assemble pluggable accessory box assemblies which have minimal height and length and which are compatible with standard 20 trunking systems. This pre-assembly and testing can be performed at a factory location, rather than at the installation site.

The mounting box 10 can be based on a standard mounting box and modified to include the pluggable connector 14. The supply wiring 25 connector 18 is a standard component.

Modifications and improvements may be made to the above without departing from the scope of the present invention. For example, although the electrical accessory has been described above as being an electrical 30 power socket, it should be appreciated that the accessory could be any

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suitable type of electrical accessory such as circuit breakers, light switches, 3 or 4 pin plugs and the like.

Furthermore, although the mounting box 10 has been illustrated and 5 described above as having a rectangular open front and rectangular walls and sides, it should be appreciated that the mounting box 10 could have an alternate shaped front, walls and sides, e.g. a circular open front etc.

Also, although the mounting box 10 has been illustrated and described 10 above as having threaded bosses for attaching the accessory 12 thereto, it should be appreciated that the box 10 may have other means for attaching the accessory thereto, for compatibility with other types of accessory.

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Claims

Claims

1. A mounting box for an electrical wiring accessory, the mounting box being adapted for mounting in a length of electrical trunking, the mounting

5 box having an open front with walls at the back, top and bottom sides and left and right end faces, wherein the mounting box is provided on at least one end face with a pluggable connector for receiving a compatible supply wiring connector within the trunking, the pluggable connector being adapted to deliver electrical power from the supply wiring connector to an 10 electrical wring accessory.

2. A mounting box for an electrical wiring accessory as claimed in claim 1, wherein the pluggable connector is mounted in an aperture of the end face of the mounting box.

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3. A mounting box for an electrical wiring accessory as claimed in claim 2, wherein the aperture is formed from knock-out portions in the end face.

20 4. A mounting box for an electrical wiring accessory as claimed in any preceding claim, wherein the pluggable connector is enclosed substantially within the mounting box.

5. A mounting box for an electrical wiring accessory as claimed in any 25 preceding claim, wherein the pluggable connector is substantially flush with the end face of the mounting box.

6. A mounting box for an electrical wiring accessory as claimed in any preceding claim, wherein the pluggable connector includes attachment

30 means for attaching the connector within the aperture.

17

7. A mounting box for an electrical wiring accessory as claimed in claim 6, wherein the attachment means comprises projections for snap-fitting into the aperture.

5

8. A mounting box for an electrical wiring accessory as claimed in any preceding claim, wherein the mounting box includes attachment means for attaching the mounting box within the trunking.

10 9. A mounting box for an electrical wiring accessory as claimed in claim 8, wherein the attachment means comprises projections for snap-fitting into the trunking.

10. A mounting box for an electrical wiring accessory as claimed in

15 claim 9, wherein a first type of projections are located on the left and right end faces of the mounting box (viewed as installed in a horizontal run of trunking).

11. A mounting box for an electrical wiring accessory as claimed in 20 claim 10, wherein the first projections may be positioned towards but slightly spaced from the open front of the mounting box for engaging the rear face of a cover portion at each end of the box.

12. A mounting box for an electrical wiring accessory as claimed in any 25 preceding claim, wherein flange portions may be provided along top and bottom edges of the mounting box open front, so as to be flush with the cover portions at the ends.

13. A mounting box for an electrical wiring accessory as claimed in any 30 of claims 9 to 12, wherein a second type of a second type of projections

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are located on the top and bottom walls of the mounting box for engaging complementary formations in side walls of said trunking.

14. A mounting box for an electrical wiring accessory as claimed in

5 claim 13, wherein the second type of projections are positioned towards the back of the mounting box, compared with the first type.

15. A mounting box for an electrical wiring accessory as claimed in any preceding claim, wherein the walls and sides of the mounting box are

10 rectangular.

16. A mounting box for an electrical wiring accessory as claimed in any preceding claim, wherein the mounting box has dimensions which conform to standards applicable in the territory.

15

17. A mounting box for an electrical wiring accessory as claimed in any preceding claim, wherein the mounting box includes threaded bosses for attaching a conventional electrical accessory thereto.

20 18. A mounting box for an electrical wiring accessory as claimed in any preceding claim, wherein the mounting box includes a pluggable connector on each end face.

19. An assembly for mounting in electrical trunking, the assembly 25 comprising and electrical wiring accessory assembled together with a mounting box according to any of claims 1 to 18, wherein a face plate of the accessory closes the open front of the mounting box and wherein the pluggable connector is pre-wired together within the assembly to deliver electrical power from the supply wiring connector to the accessory without 30 disassembly of the accessory from the mounting box.

19

20. An assembly for mounting in electrical trunking as claimed in claim 19, wherein the area of the face plate of the accessory is larger than the area of the open front of the mounting box.

5

21. An assembly for mounting in electrical trunking as claimed in claim 19 or 20, wherein, where the mounting box includes projections of the first type, a gap is then formed between those projections and the mounting box and the underside of the face plate of the accessory.

10

22. An assembly for mounting in electrical trunking as claimed in claim 21, wherein the mounting box may further be provided with flange portions extending along top and bottom sides abutting the face plate of the accessory, at a depth corresponding to the gap at the end walls.

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23. An assembly for mounting in electrical trunking as claimed in any of claims 19 to 22, wherein the pluggable connector does not protrude through the aperture further than the distance the face plate extends over front of the mounting box.

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24. An assembly for mounting in electrical trunking as claimed in any of claims 19 to 23, wherein the projections do not extend further than the distance the face plate extends over front of the mounting box.

25 25. An electrical installation comprising:

at least one section of electrical trunking mounted within a building:

and at least one assembly according to any of claims 19 to 24 mounted within the trunking.

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20

26. An electrical installation as claimed in claim 25, wherein the installation comprises a plurality of assemblies.

27. A method of installing a mounting box in a section of electrical 5 trunking comprising the steps of:

providing a mounting box having an open front with walls at the back, top and bottom sides and left and right end faces;

providing at least one end face of the mounting box with a pluggable connector for receiving a compatible supply wiring connector; 10 attaching the mounting box within the section of trunking; and plugging the supply wiring connector into the pluggable connector.

28. A method of installing a mounting box in a section of electrical trunking as claimed in claim 27, wherein electrical continuity between

15 sections of supply wiring is provided through plugged connections at both ends of the mounting box.

29. A method of installing a mounting box in a section of electrical trunking as claimed in claim 27 or 28, wherein the method further

20 comprises the preliminary step of wiring an electrical accessory to the pluggable connector and attaching the electrical accessory to the mounting box before the mounting box is attached within the trunking.