GB2609959A

GB2609959A - Electrical junction boxes

Info

Publication number: GB2609959A
Application number: GB2111876.5A
Authority: GB
Inventors: Stephen Bungay Matthew
Original assignee: Quick Fix Ip Ltd
Current assignee: Quick Fix Ip Ltd
Priority date: 2021-08-18
Filing date: 2021-08-18
Publication date: 2023-02-22
Also published as: GB202111876D0

Abstract

An electrical junction box comprises a back box 22, including an insulating enclosure having a front face 42 and a rear face 40, electrical terminals 46 for connecting to AC power, an AC power regulation element i.e. sockets 26, 28 (Figure 2) or switches 30, 32 (Figure 2) accessible from the front face of the enclosure, and electrical conductors 44 contained within the enclosure and connecting the terminals to the AC power regulation element, the enclosure including an attachment means for securing the rear face to a wall, a fascia 24 plate attachable over at least a part of the front face of the back box and including at least one aperture allowing employment of the AC power regulation element. Thus, a usable socket or switch can be provided during the first fix process, which can be used safely by subsequent contractors. The fascia plate can be fitted quickly, easily, and without needing the attention of skilled tradespeople after the necessary decorative work has been completed. Levelling screws may be included.

Description

Electrical junction boxes

S

FIELD OF THE INVENTION

The present invention relates to electrical junction boxes, including sockets, switches, and the like.

BACKGROUND ART

The usual process of providing the necessary electrical infrastructure to a new building is for a contractor with the necessary electrical certification (in the UK, NICEIC certification) to attend once the physical structure of the building is complete but before the internal walls are finished for what is referred to as "first fix". The contractor lays the cables necessary for the intended electrical power provision, and will usually fit a "back box" where sockets, switches, etc are to be provided. A back box is a simple structure, often of steel, usually cuboid with 5 faces present and the front face open, which can be attached to the internal wall via its rear face and which carries suitable threaded lugs to which the socket or switch can be screwed. The side faces of the back box have apertures or areas which can be removed, to allow cables to be introduced into the box for connection to a socket or switch. A steel structure of the box allows for earth connections to be made easily. The contractor will then leave the building with back boxes installed, and cables leading to the back boxes as needed with some slack cable protruding from the box.

Other contractors can then attend to complete the internal fit-out of the building, providing the decorative internal wall facing (usually a plasterboard finish and/or a plaster render or skim applied to the masonry walls), leaving holes around the back boxes and finishing/painting the internal wall around the back boxes. Once this is done, the electrical contractor can return for the so-called "second fix", fitting switches and sockets to the back boxes over the decorative finish. The second fix process needs to be delayed until after the other fit-out steps are complete, since the fit-out will usually include a painting or a decorating step; the fascia plates of the switches and sockets are designed to overlap the wall surface around the hole in order to provide a neat finish. The paint should extend behind the edges of the fascia plate, and the visible front surface of the fascia plate needs to be kept clean of paint and the like. Therefore the second fix needs to take place after the fit-out is otherwise complete. The second fix requires the attendance of a qualified electrical contractor, since it involves connecting live cables to the socket.

SUMMARY OF THE INVENTION

This process is inefficient. It requires the electrical contractor to attend twice, thus increasing the time they spend on site and (often) causing scheduling delays. The electrical contractor will usually need to supply more cable than will be needed in order to allow for adjustment in the second fix, so cable will be wasted. The other contractors must provide their own electrical supply for any powered tools that they wish to use, since although the majority of the electrical infrastructure is present, the necessary sockets are not yet present thus power cannot safely be connected at that stage. Loose live cables should be terminated with an appropriate termination block even at this stage, but it is very common for them to be rolled up, taped and pushed into the back box. In this state, it is possible for the cables to become live if (through human error) the wrong circuit is switched on, presented a clear health & safety hazard.

The present invention therefore provides an electrical junction box, comprising a back box, including an insulating enclosure having a front face and a rear face, electrical terminals for connecting to AC power, an AC power regulation element accessible from the front face of the enclosure, and electrical conductors contained within the enclosure and connecting the terminals to the AC power regulation element, the enclosure including an attachment means for securing the rear face to a wall, a fascia plate attachable over at least a part of the front face of the back box and including at least one aperture allowing employment of the AC power regulation element.

Thus, the present invention permits a usable socket or switch to be provided during the first fix which can (if necessary) be used safely by subsequent contractors, whilst ensuring that the final fascia plate can be fitted quickly, easily, and without needing the attention of skilled tradespeople after the necessary decorative work has been completed.

The AC power regulation element can be a switch, in which case the at least one aperture is preferably sized and positioned on the fascia plate to allow the switch to project through the at least one aperture when the facsia plate is fitted to the back box.

Alternatively (or in addition) the AC power regulation element can be a socket, in which case the at least one aperture is preferably sized and positioned on the fascia plate to allow a pin of an AC plug to project through the at least one aperture and engage in the socket when the facsia plate is fitted to the back box. A plurality of apertures can be provided in the facsia plate, corresponding to a plurality of openings of the socket. In an alternative arrangement, the at least one aperture can allow access to a conductor within the fascia plate, which is electrically connected to a pin protruding from the facsia plate that is sized and positioned such that, when the fascia plate is fitted to the back box, the pin projects into an opening of the socket.

There can be a plurality of AC power regulation elements in the back box, and a corresponding plurality of apertures in the fascia plate. They may be of the same type or of different types.

The terminals are ideally recessed into the rear face of the insulating enclosure.

We prefer that the height and width dimensions of the fascia plate exceed those of the back box so that the facsia plate, when fitted to the back box, completely covers the back box.

Adjustable levelling screws can be provided, able to project from the rear face of the back box, to allow the back box to be adjusted so that the fascia plate fits neatly against the internal wall facing.

By "junction box" we mean an enclosed item in which electrical terminations are or can be made. The term is commonly applied to enclosures allowing connections between cables, but as shown the invention particularly (although not exclusively) applies to switches and sockets and we use the term "junction box" to encompass these also.

As a result of the invention, all cables can be terminated satisfactorily from the first installation. This removes the risk of an electrical shock by allowing the construction workers to ensure that there are no exposed conductive parts, with all cables being terminated into the block provided and fixed into place.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described by way of example, with reference to the accompanying figures in which; Figure 1 shows a first embodiment of the invention, in place and complete, with part of the wall lining cut away for clarity; Figure 2 shows the back box of the first embodiment, from the front; Figure 3 shows the elements of the junction box of the first embodiment, in exploded form; Figure 4 shows the back box of the first embodiment, with wiring connected; Figure 5 shows the back box of the first embodiment being fitted to a wall; Figure 6 shows the junction box of the first embodiment being finished; Figure 7 shows the junction box of a second embodiment of the present invention; Figure 8 shows the back box and the fascia plate of the second embodiment, 20 separated; Figure 9 shows the back box of the second embodiment, in exploded form; Figure 10 shows a rear view of the back box of the second embodiment; Figure 11 shows the junction box of a third embodiment of the present invention; Figure 12 shows the back box and the fascia plate of the third embodiment, separated; and Figure 13 shows the back box and the fascia plate of the third embodiment, separated, form the rear;

DETAILED DESCRIPTION OF THE EMBODIMENTS

As noted above, the present invention relates to electrical junction boxes. This is intended to cover the range of AC electrical supply elements that are fitted within buildings, including residential and commercial buildings, such as electrical sockets, electrical switches, electrical outlets, and the like.

Figures 1 to 6 show a first embodiment, in the form of a switched AC electrical outlet or socket. Figure 1 shows the socket 10 in place after installation, fixed to a wall 12 which has been finished with a plasterboard or dry-lining facing 14, shown partly cut away for clarity.

This is, as normal, spaced from the wall 12 by battens 16 of wood (or other material) which are affixed to the wall by any convenient process such as screws, nails, glue or the like; the plasterboard 14 can then be nailed, glued, screwed or otherwise attached to the batten 16. It will usually be "skimmed", i.e. covered with a thin layer of plaster to take up any surface imperfections such as the nail heads and joins between adjacent boards, and painted. A plug 18 with a power cord 20 is shown in place in the socket 10.

The socket comprises a back box 22 which is attached to the surface of the wall 12 and is thus located mainly in the space between the wall 12 and the plasterboard 14, created by the thickness of the battens 16. A fascia plate 24 is attached to the front face of the back box 22, and both are dimensioned so that the fascia plate sits in front of the plasterboard layer 14 and is held tight against it in an aesthetically neat manner.

Referring to figure 2, the back box include a standard set of apertures 26, 28 for a pair of B51363 electrical sockets, together with associated switches 30, 32. A pair of internally-threaded holes 34, 36 allow the fascia plate 24 to be secured in place over the back box 22 via correspondingly-threaded bolts 38 or another suitable fixing.

Figure 3 shows the socket in exploded form. The back box 22 comprises a rear face 40 and a front shell 42 which are screwed (or otherwise fixed) together to define a cuboid shell. Within this shell there are a plurality of electrical conductors 44 which lead from a set of terminal blocks 46 to a set of socket contacts 48. The terminal blocks 46 are conventional screw terminals, or crimp, push and twist or push-in type connectors and are sufficient in number to receive (in this case) an incoming and an outgoing electrical supply cable to form a ring main circuit. In other examples they will be ample to receive whatever pattern of cables is needed for the specific junction box in question. The terminal blocks 46 are mounted securely within the back box 22 and accessible from the rear via an opening 50 in the rear face 40. The socket contacts 48 are in the shape, configuration and position (relative to the front of the fascia plate 24 when fitted) as defined by the specific electrical standard with which the socket is intended to comply -in this case British Standard 1363. They are located as necessary behind the apertures 26, 28 on the front of the back box 22 so that they can be accessed through the apertures 26, 28 by the pins of a suitably compliant design of plug.

The rear face 40 has a plurality of mounting holes 52 to allow it to be fixed in place on a wall using conventional screw fixings or the like. Openings 54 are provided on the front face of the front shell 42 to receive threaded fixings to retain the fascia plate 24 in position over the back box 22. These threaded fixings can be secured into internally-threaded bosses 56 formed on the earth elements 58 of the electrical conductors 44 in order to ensure compliance with electrical design codes.

A pair of tabs 60 are provided on the two lateral sides of the back box 22. In this example, they are hinged and can be rotated about a horizontal axis perpendicular to the rear face 40 to bring them from a retracted position alongside the side walls of the front shell 42 into a deployed position in which they project outwards from the side walls. Alternatively, they may be fixed or moulded integrally in place in the deployed position. In the deployed position, they act as a marker for where the rear face of a standard-thickness plasterboard dry-lining should be positioned in order to ensure that the front face is correctly positioned relative to the back box 22 and the fascia plate 24. This assists during the fit-out process.

Figures 4 to 6 illustrate schematically the fitting process. First, the electrical supply cables 62, 64 are connected to the terminal blocks 46 at the rear of the back box 22 in the usual manner. Next, the back box 22 is fitted to a wall via the mounting holes 52. The wall is then dry-lined, skimmed, and painted. During this process, the socket can be used by the various tradespersons involved, in the event that they need electrical power. Once that is complete, the fascia plate 24 is screwed to the back box 22. As shown in figure 6, the fascia plate 24 has sets of apertures 66 which correspond to both the pattern required for the electrical standard to which the socket conforms, and to the apertures 26, 28 on the front face of the back box 22, behind which the socket contacts 48 are located. Thus, an electrical plug can be inserted into the set of apertures 66 and its pins will extend through these, through the apertures on the back box 22, and make contact with the socket contacts 48.

The fascia plate also has switch apertures 68 allowing the switch elements 30, 32 on 5 the back box 22 to project through and be operated by a user. The depth of the switch elements should of course be adjusted so that the switches are a suitable height given the thickness of the fascia plate 24.

Figures 7 to 10 illustrate a second embodiment of the invention. This largely corresponds in structure to the first embodiment, but is aesthetically different and simpler in construction. Thus, a back box 122 has two sets of BS1363 apertures 166 on its front face, and contains contacts behind those apertures linked conductively to a set of terminal blocks 146 accessible from the rear face. As with the other embodiments described herein, more or fewer than two sets of apertures 146 could be provided if a greater or lesser number of sockets is desired, and the BS1363 pattern of apertures could be replaced with any other required socket pattern such as those referred to above.

The rear face 140 is in the form of a non-conductive plate (of a suitable mouldable plastics material) which is attached to the rear of the back box 122 in order to help define the enclosure within which the electrical conductors are provided. It has an opening 150 via which the terminal block 146 is accessible and a cranked section 170 allowing easy access for cables to the terminal block 146 by defining a channel extending from an upper edge of the back box 122 to the terminal block 146.

A fascia plate 124 is attachable over the back box 122. Screws 138 can be fitted, securing in blind bosses in the back box 122, to retain the fascia plate 124 securely in place. The fascia plate 124 has sets of apertures 172 corresponding to the apertures 166 on the back box, allowing an AC plug to be inserted through the fascia plate into the sockets defined in the back box 122. It also has openings corresponding to the shape of switches on the back box 122, provided to enable or disable the individual sockets, which therefore project through the openings in the fascia plate 124 to allow them to be actuated.

Figures 11 to 13 illustrate a third embodiment. This is structurally similar to the first and second embodiments in that it comprises a back box 222 and a fascia plate 224 that can be attached to the back box 222 via screws 238, with a terminal block 246 in the back box 222 for accepting AC supply cables (not shown). In this embodiment, the terminal block 246 is accessible via a top surface of the back box 222, however.

In this third embodiment, the socket presented by the back box 222 is an IEC 60320 C14 connector 174. The fascia plate 224 has a pair of B51363 sockets 266 on its front face and conductors within it connecting these sockets electrically to an IEC 60320 C13 connector 176 on its rear face. This is positioned to correspond to the C14 connector 174 on the back box 222, and thus when the fascia plate 224 is attached to the back box 222, the C13/C14 connectors 174, 176 mate and an electrical connection is made from the terminal block 246 to the sockets 266. Fitting the fascia plate 224 does not require any electrical terminations to be made, broken or reconfigured, so does not require attendance of a skilled tradesperson.

Prior to fitting the fascia plate 224, the IEC 60320 connector on the back box 222 is accessible and can therefore be used as an electrical supply by tradespeople working to construct the building in question.

Note that figure 12 illustrates a C14 (i.e. male) connector on the back box 222 and figure 13 illustrates a C13 (female) connector on the fascia plate 224, but in practice it is probably better to reverse this arrangement so that the live back box connector 174 is a female connector (such as C13) to reduce the risk of electric shock.

Of course, the C13/C14 connectors 174, 176 could be replaced with any preferred plug/socket pairing. A C13 connector is preferred since cables that are compatible with these are widely available.

One useful addition to the above-described embodiments would be to provide a more convenient way to align the back box to the surface on which it is mounted. This could be (for example) a set of threaded lugs on some or all of the corners of the casing, where levelling screws can be screwed in thereby pushing the box away from the wall to level it, as well as providing tension to ensure a secure fit. Such adjustable levelling screws, able to project from the rear face of the back box, could (for example) be integrated into the mounting holes 52 of the first embodiment.

The above-described embodiments relate to junction boxes in the form of electrical sockets. The present invention is equally applicable to other electrical junction boxes that may be required within buildings, such as electric switches for controlling lighting, heating, cooking and other circuits. Switches and the like can be provided for in the same manner as the socket switches of the first embodiment, for example.

The three embodiments all illustrate a standard United Kingdom electrical socket, i.e. one made to British Standard 1363 (also known as IEC Type G) but the invention is of course applicable to any applicable standard electrical socket design such as IEC 60906-1 or any individual national standard such as a Schuko or other CEE 7 socket, a NEMA socket, or the like.

It will of course be understood that many variations may be made to the above-described embodiment without departing from the scope of the present invention.

Claims

CLAIMS1. An electrical junction box, comprising a back box, including an insulating enclosure having a front face and a rear face, electrical terminals for connecting to AC power, an AC power regulation element accessible from the front face of the enclosure, and electrical conductors contained within the enclosure and connecting the terminals to the AC power regulation element, the enclosure including an attachment means for securing the rear face to a wall; a fascia plate attachable over at least a part of the front face of the back box and including at least one aperture allowing employment of the AC power regulation element. 2. 3. 4. 5. 6. 7.
An electrical junction box according to claim 1 in which the AC power regulation element is a switch.
An electrical junction box according to claim 2 in which the at least one aperture is sized and positioned on the fascia plate to allow the switch to project through the at least one aperture when the facsia plate is fitted to the back box.
An electrical junction box according to claim 1 in which the AC power regulation element is a socket.
An electrical junction box according to claim 4 in which the at least one aperture is sized and positioned on the fascia plate to allow a pin of an AC plug to project through the at least one aperture and engage in the socket when the facsia plate is fitted to the back box.
An electrical junction box according to claim 5 in which there are a plurality of apertures in the facsia plate, corresponding to a plurality of openings of the socket.
An electrical junction box according to claim 4 in which the at least one aperture allows access to a conductor within the fascia plate which is electrically connected to a pin protruding from the facsia plate that is sized and positioned such that, when the fascia plate is fitted to the back box, the pin projects into an opening of the socket.
8. An electrical junction box according to any one of the preceding claims in which there are a plurality of AC power regulation elements in the back box, and a corresponding plurality of apertures in the fascia plate.
9. An electrical junction box according to any one of the preceding claims in which the terminals are recessed into the rear face of the insulating enclosure.
10. An electrical junction box according to any one of the preceding claims in which the height and width dimensions of the fascia plate exceed those of the back box and the facsia plate, when fitted to the back box, completely covers the back box.
11. An electrical junction box according to any one of the preceding claims, including adjustable levelling screws able to project from the rear face of the back box.