GB2481076A

GB2481076A - Electrical back box with flange

Info

Publication number: GB2481076A
Application number: GB201010781A
Authority: GB
Inventors: Richard David Brook
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-06-10
Filing date: 2010-06-10
Publication date: 2011-12-14
Anticipated expiration: 2030-06-10
Also published as: GB2481076B; GB201010781D0

Abstract

An electrical back box for use in the electrical supply industry has an outwardly-projecting flange 28 which, when the back box is in position in a recess in a wall, lies against the wall and covers any gap around the box, thus preventing the ingress of foreign bodies. The flange may taper in thickness towards its outer edges, and may be integrally injection moulded with the box from a plastics material such as polypropylene. The flange may be luminous.

Description

Improved Electrical Back Box

CROSS REFERENCE TO RELATED APPLICATIONS

This application represents the first application for a patent directed towards the invention and the subject matter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved electrical back box for use in the electrical installation industry.

2. Description of the Related Art

It is known to provide electrical accessory back boxes, either one or two-gang made of pressed steel, in accordance with BS 4662:2006. Such back boxes occasionally need to be replaced, disrupting the plaster of the wall surrounding them. The plaster must be made good so as to avoid the risk of ingress of foreign bodies in compliance with REG 522.4 of lEE REGS BS7671.

It is also known, when refurbishing electrical installations, to provide a temporary safety shield for electrical boxes, as disclosed in UK patent number 2 457 520 B, Brook and Krlic. The temporary safety shield permits the supply of power while works such as wall plastering are carried out, and the shield is * then removed; the electrical back box remains in situ throughout so that electrical power can be supplied through it.

It is further known to provide "finger plates" surrounding electrical switches. The plates, usually made of a plastics material, protect the wall S...

around a switch from fingermarks. Such plates have no electrical connections.

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* Usually the plates are one-gang and not two-gang.

The prior art will be described with reference to Figure 1; Figure 1A is a sectional side view and Figure lB is a front view of an electrical back box taken from BS4662:2006. A standard one-gang box has a square metal back plate 10 and four walls 12 perpendicular to the back plate, thus forming a square open-fronted box. On each wall 12 towards the open front is a lug 14 having a tapping 16.

In use the square box is placed in a recess in a plaster wall so that the open front is level with the wall surface and is secured by fixing screws (not shown) through apertures in the back plate 10. A power supply cable (not shown) is connectable to a square switch plate (not shown) which forms the front of the box and which is secured to the four tapped lugs 14. The switch plate stands slightly proud of the wall.

BRIEF SUMMARY OF THE INVENTION

According to the present invention an electrical back box comprises a rectangular box having an open front face, aperture means to permit passage of an electrical supply cable into the box; and around the open front face a flange projecting outwardly of the open front face.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, Figure 1 shows the prior art. The invention will be described by way of example only with reference to: Figure 2A which is a sectional side and Figure 2B which is a front view of a one-gang box according to the invention; Figure 3 which illustrates installation of the one-gang box of Figure 2; and Figure 4A which is a sectional side view and Figure 4B which is a front view of a two-gang box according to the invention.

BRIEF DESCRIPTION OF THE BEST MODE FOR CARRYING OUT THE

* 25 INVENTION Figures 2A and 2B Figures 2A and 2B illustrate a one-gang box 21 comprising a square back plate 20 and four walls 22 perpendicular to the back plate 20, thus forming a square, open-fronted box. On each wall 22 towards the open front is a lug 24 having a tapping 26.

Around all four walls 22 at the open front of the box 2lis an outwardly-projecting flange 28. The flange tapers in thickness so that the outer edge 30 is thinner than the part 32 near the walls 22.

Preferably the box 21 comprising the back plate 20, walls 22 and flange 28 are made of a plastics material such as polypropylene(?). Preferably the box 21 is a one-piece injection(?) moulding.

Figure 3 Figures 3 shows the method of installation of the box 21, which is illustrated adjacent to a recess 40 in a plaster wall 42. The cavity 40 is slightly larger than the dimensions of the back plate and walls 22 of the box 21 so that the box 21 can be placed within the recess 40. Around the recess 40 the plaster is shown to be broken, 44. Within the cavity 40 is an electrical power cable 46.

The back plate 20 of the box 21 has a pair of fixing apertures 30 and the box 21 can be fixed to the rear of the cavity 40 by fixing screws 34. The back plate 20 has an aperture 32 through which the cable 46 can pass.

When the box 21 is fixed in the cavity 40, the flange 28 covers the *.. 20 broken plaster 44 and no making-good is necessary. The taper in the flange is arranged so that the rear face of the flange lies parallel to and in contact with the plaster wall 42, the taper of the flange 28 providing minimum obstruction ::::. when the wall is touched.

Typically flange 28 will have a thickness of ?? millimetres at part 32 25 near the walls 22, and a width W of 10 millimetres.

Once the back box 21 is in place a light switch cover or the like can be 0***** * 1 connected to the electrical cable 46 and releasably fixed to the tapped lugs 24 by screws (not shown).

Figures 4A and 48 Figures 4A and 4B illustrate respectively side section and front views of a two-gang box 51 having a rectangular back plate 50 and four waIls 52 carrying an outwardly-projecting tapering flange 58. There are two apertures 54 for power cables. Other features of the two-gang box are similar to the one-gang box.

The back boxes 21 ad 51 can, in a variation, be made of a luminous material so as to indicate the position of a light switch in a dark room. *.*S * I I...

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Claims

Claims 1. An electrical back box comprises a rectangular box having an open front face, an aperture to permit passage of an electrical supply cable into the box, and around the open front face a flange projecting outwardly of the open front face.
2. An electrical back box according to claim 1, in which the flange is arranged so that when the box is placed in a recess in a wall, the flange is in contact with the wall around the recess.
3. An electrical back box according to claim 1 or claim 2, in which the flange decreases in thickness towards its outer edges.
4. An electrical back box according to any preceding claim in which the rectangular box and the outwardly-projecting flange are made of a plastics material.
5. An electrical back box according to claim 4, in which the box and the flange are formed from a single moulding.
6. An electrical back box according to claim 4 or claim 5, in which the plastics material is polypropylene. * I.
7. An electrical back box according to any preceding claim which is S..* 25 made of a luminous material. * S.. * . *...
8. An electrical back box substantially as described herein with reference to the accompanying drawings.Amendment to the claims have been filed as follows Claims 1. A method of installing an electrical fitting in a recess in a wall comprises inserting in the recess an electrical back box comprising: a rectangular box having an open front face, an aperture to permit passage of an electrical supply cable into the box, and around the open front face a flange projecting outwardly of the open front face, whereby the flange covers the space between the back box and the recess; and attaching an electrical fitting to the back box.2. A method according to claim 1, in which the flange is brought into contact with the wall around the recess.3. An electrical back box for use in method according to claim 1 or claim 2, the box being rectangular and having an open front face, an aperture to permit passage of an electrical supply cable into the box, and around the open front face a flange projecting outwardly of the open front face.4. An electrical back box according to claim 3, in which the flange is arranged so that when the box is placed in a recess in a wall, the flange is in contact with the wall around the recess.5. An electrical back box according to claim 3 or claim 4, in which the flange decreases in thickness towards its outer edges.6. An electrical back box according to any one of claims 3 to 5 in which the rectangular box and the outwardly-projecting flange are made of a S.....plastics material. * *. * . .7. An electrical back box according to claim 6, in which the box and the flange are formed from a single moulding. * S...8. An electrical back box according to claim 6 or claim 7, in which the plastics material is polypropylene.
9. An electrical back box according to any one of claims 3 to 8 which is made of a luminous material.
10. An electrical back box substantially as described herein with reference to the accompanying drawings. **..* * *S****** * * * ** * * S S.. * a...S S...