GB2175456A

GB2175456A - Electrical consumer unit

Info

Publication number: GB2175456A
Application number: GB08611857A
Authority: GB
Inventors: Graham Birkedale; Edward Andrew Murphy
Original assignee: CITY ELECTRICAL FACTORS Ltd
Current assignee: CITY ELECTRICAL FACTORS Ltd
Priority date: 1985-05-17
Filing date: 1986-05-15
Publication date: 1986-11-26
Also published as: GB8611857D0; GB2175456B

Abstract

An electrical consumer unit is in the form of a rectangular box having removable, shorter side walls (13) and fixed longer side walls (11, 12), Each fixed side wall is extended through 90 DEG at both its ends to provide guide portions (21). At each corner of the unit are respective upstanding ribs (26). Opposite pairs of guide portion (21) and rib (26) form means to locate respective thickened portions at the ends of a side wall (13) to hold the side wall in place between the portions (21). The wall can then only be removed by sliding it clear of the location means. If a side wall (13) is removed from two such units, the units can be placed in contact along their respective open sides and connected together to form a larger composite unit by the use of confection means (35) in the form of flanged channel members engaging guide portions (21). <IMAGE>

Description

SPECIFICATION Electrical consumer unit This invention relates to an electrical consumer unit for connection into an electrical supply circuit and intended to contain such items as fuses and/or circuit breakers and possibly also an isolating switch. An object of the invention is the provision of such a unit in a form which allows a plurality of the units to be connected together to form a larger composite unit.

According to the invention an electrical consumer unit comprises a base and at least two peripheral side walls, one of which is removable, location means provided on the unit, and connection means for releasable engagement with the location means, the arrangement being such that, in use, a pair of said units, each with said side wall removed, can be placed together along the empty sides respectively, and the or each connection means engaged with the location means of the units, thereby releasably securing the units together to form a composite larger unit.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which.

Figure 1 is a top plan view of one form of an electrical consumer unit of the invention, with a cover thereof shown in place thereon, Figure 2 is the same view as Fig. 1, but with the cover removed.

Figure 3 is an exploded, fragmentary view, to a larger scale, illustrating how a removable side wall of the unit engages with a base and another side wall thereof, Figure 4 is a top plan view, on the scale of Figs. 1 and 2, of a pair of the units of Fig. 2 secured together, with a further removable side wall of one of the units shown in a position removed from its unit, Figure 5 is a perspective view of the unit of Fig. 4, with the cover of Fig. 1 shown thereon, and Figure 6 is an exploded, fragmentary view to the same scale as Fig. 3, of connection means and corresponding location means on the pair of units to be connected and with which the connection means engage.

The consumer unit shown in Figs. 1 and 2 is in the form of a rectangular box having a base 10, longer side walls 11, 12 and shorter side walls 13, 14. The box is made of plastics material, for example by injection moulding. The side walls 11, 12 are integral with the base but, in this example, both the side walls 13, 14, are removable, as will be described. Alternatively the removable sides could be longer than the integral ones.

The base 10 is generally flat but has a pair of aligned, rectangular upstanding posts 15, 16. Each post has a hole suitable for a selftapping screw. The posts are provided for mounting a din rail and the base will be provided with 'knock-out' portions (not shown) for reception of electrical trunking through which electrical cables are led to fuses or circuit breakers in the box, in use. Adjacent each side wall 11, 12 a pair of circular flanges 18 surround respective holes through the base to allow for fixing screws or the like to secure the box to a surface. Adjacent each flange 18 is an upstanding tubular column 19 having a hole to suit a self-tapping screw to secure a cover 20 as will be described. Alternatively each column 19 may have a fixture to secure the cover by means of a special screw requiring only a 90" turn to lock it against axial withdrawal.Each column terminates below the top of the side walls (Fig. 3). A secondary cover may be provided if required.

For one pair of opposed columns 19, a short, upstanding, flat-topped support 1 9a is connected to the column and adjacent shorter side wall. The supports 19a are used to support an earth and neutral rail assembly fitted between the supports by self-tapping screws.

For the other pair of opposed columns, a similar, but taller stepped support 19b is likewise provided, the support 1 9b being stepped at one column only. This lower step is to support a live copper busbar by means of a selftapping screw into a fixing hole. The higher support platforms are to fix a live busbar insulation shield by means of self-tapping screws in fixing holes. The supports are on the sides of the columns away from the side walls 13, 14.

The two side walls 11, 12 each continue through 90" at both their ends to form guide portions 21 for location of the removabvle side walls 13, 14. Each guide portion has a slight taper so that its width increases downwardly, and defines a sloping surface 22 (Figs.

3 and 6) facing in the same direction as the inner surface of its associated side wall. Thus, the surfaces 22 at the respective ends of one longer side wall face the respective surfaces 22 of the other longer side wall. Between opposing surfaces 22 extends a base rib 23 extending slightly above the level of the remainder of the base, the rib having the same width as the surfaces 22 at its ends. Alongside the base rib extends a base groove 24, the groove running across the box between side walls 11 and 12.

At each end of the groove, an adjacent portion of the side wall 11 or 12, is provided with a further guide portion comprising a rib 25 extending perpendicularly from the inner surface of the side wall and terminating a little way below the top of the side wall, and a rib 26 spaced from the inner surface of the side wall and extending from the rib at right angles to terminate at the edge of the base groove 24. The rib 26 extends slightly higher than the rib 25 but still terminates below the top of the side wall with which the further guide por tion is integrally formed.

Both side walls 11, 12 have a step 27 forming a lip in its upper surface, the lip continuing on the top surface of the guide portions 21.

The two side walls 13, 14 are identical and each have a generally flat outer surface. The inner surface can be provided, like the base, with 'knock-out' portions. The top surface of each side wall 13, 14 has the same step 27 forming a lip, as the side walls 11, 12 so that with all the side walls present, the lip is continuous around the box.

The thickness of each of the side walls 13, 14 matches the thickness of the surfaces 22, between an opposing pair of which a side wall 13 or 14 fits. Moreover, the end surfaces of each side wall 13 or 14 are sloped to match the slope of the surfaces 22. Thus the side wall lower surface rests on the base rib 23 with its upper surface at the same level as the upper surface of each longer side wall.

However, at each of its ends, a side wall 13 or 14 has on its inner surface a thickened portion 28. The portion 28 generally has a thickness corresponding the width of the base groove 24 and a bottom part 29 of the portion 28 extends below the lower surface of the side wall so that it rests on the bottom of the groove when the side wall lower surface rests on the base rib. The portion 28 extends sidewardly beyond the sloping end surface of the side wall so that on engagement of the shorter side wall with the remainder of the box, it is retained between the guide portion 21 and the rib 26.

At its top, the portion 28 has a platform 30, which extends over the top of the rib 26, and a short rib 31 extending downwardly from the platform and at right angles to the portion 28, the rib 31 fitting in the space between the rib 26 and the inner surface of the shorter side wall. Finally, it can be seen from Fig. 3 that a number of projections, one of which is shown at 32, extend downwardly from the inner surfaces of each side wall 13 or 14, and like the part 29 rest in the base groove 24.

It can thus be appreciated that both shorter side walls 13, 14 can be easily slid into or out of engagement with the remainder of the box. When both sides are in engagement, the cover 20 is normally secured on to the box, the cover having a short downward peripheral flange extending from its top surface, the flange having a lip in its downwardly facing surface complementary to the lip formed by the step 27 in the upper surface of each side wall. The cover thus readily engages on the top of the box and, in one example, screws, not shown, can be passed through holes 33 in the top of the cover and engaged in the columns 19 to secure the cover to the box.

Alternatively, as mentioned, a special screw requiring only a 90" turn can be passed through a hole 33 into a column 19 to secure the cover in place. In this case, the screw has opposite diametral extensions from its shank, and the circular holes 33 have corresponding opposite diametrally extending slots to receive the screw extensions in one orientation, but to prevent return of them through the slots when the screw is rotated by 90". The top of the cover has an opening 34 through which said fuses or circuit breakers in the box, in use, can protrude. The cover prevents the side walls 13, 14 sliding out if the box is inverted or tilted.

If it is found that the consumer unit box described is too small, it is possible to form a larger, composite unit by combining two or more boxes as will now be described.

To combine two boxes, it is necessary for one shorter side wall from each box to be removed. The two boxes are then placed against one another as shown in Figs. 4 and 5 with the respective two empty sides together. To connect the boxes, connection means 35 is used. This is shown in Fig. 6 and is in the form of a flanged channel member. One connection means is used between each pair of abutting guide portions 21.

The channel has inner side surfaces 36, 37 which increase in depth along the length thereof to match the increase in the amount by which the guide portion 21 extends outwardly from the side wall 11 or 12. The channel side walls 38, 39 each have a thickness substantially matching the width of the base groove 24 and the flanges 40, 41 each have a thickness just less than the spacing of the rib 26 from the inner surface of the side wall 11 or 12, and have a length slightly less than the spacing between facing surfaces of the guide portion 21 and the rib 25.

The connection means can thus be slid over respective abutting guide portions 21 of a pair of boxes, with the guide portions being received in the channel between the side surfaces 36, 37. The channel side walls and flanges are received between the guide portions 21 and ribs 25, 26 at both boxes, which thus act as location means for the connection means 35. By the use of two connection means 35 in this way, the two boxes are thus firmly secured together, with the lower surface of the means 35 resting on the respective abutting base ribs 23 of the two boxes. At its other end, the upper surface of the connection means 35 is formed with a finger grip part 42 extending perpendicularly away from the channel outer surface, to enable the means 35 to be disengaged from the boxes. This upper surface terminates level with the lower surface of the step formed around each box, thereby allowing a pair covers 20 to be fitted to the boxes respectively in the same manner as already described, once the boxes have been joined.

It will be apparent that any number of boxes can be joined along their 'empty' sides in this manner, as required, to form a consumer unit of required capacity. The units need not be rectangular boxes or, in fact, four sided, and the location means could instead be external rather than internal of the unit. Moreover, the location means need not be adjacent along the sides as shown.

Claims

1. An electrical consumer unit comprising a base and at least two peripheral side walls, one of which is removable, location means provided on the unit, and connection means for releasable engagement with the location means, the arrangement being such that, in use, a pair of said units, each with said side wall removed, can be placed together along the empty sides respectively, and the or each connection means engaged with the location means of the units, thereby releasably securing the units together to form a composite larger unit.

2. A unit as claimed in claim 1, wherein the location means comprise a pair of spaced, aligned guide and rib combinations.

3. A unit as claimed in claim 2, wherein the removable peripheral wall engages with the unit by way of said location means, end surfaces of the wall engaging facing surfaces of the pair of guides respectively to prevent longitudinal movement of the wall, and respective ends of the walls engaging between the guide and rib combinations to prevent lateral disengagement of the wall from the unit, removal or engagement of the wall taking place by sliding the wall away from or towards the base.

4. A unit as claimed in claim 3, wherein a groove provided in the base of the unit extends between the guide and rib combinations, and part of the wall is engaged therein to resist lateral disengagement of the wall from the unit.

5. A unit as claimed in any one of claims 2 to 4, wherein the connection means comprise a pair of members for engagement with adjacent guide and rib combinations of two side-by-side units respectively, each member holding adjacent guides of the two units against each other and being held against movement away therefrom by adjacent ribs of said side-by-side units, removal or engagement of the member being by sliding it away from or towards the common base formed by the two units.

6. A unit as claimed in claim 5, wherein each member is of flanged channel form, the adjacent guides being received in the channel and the flanges being received behind said adjacent ribs.

7. A unit as claimed in any one of claims 2 to 6, wherein the unit is four sided, having a pair of opposed, fixed, peripheral side walls, and a further pair of opposed peripheral side walls at right angles to said fixed side walls, at least one of said further pair being removable, the rib of each guide and rib combination being parallel to but spaced from an inner surface of one of said fixed side walls, the rib, at its end remote from its associated guide, being connected to the side wall by a further rib extending perpendicularly from said inner surface, and each guide being a continuation of a fixed side wall.

8. A unit as claimed in claim 7 as appended to claim 4, wherein said end of the rib nearest its associated guide terminates flush with one edge of the groove in the base, and a facing surface of its associated guide terminates flush with the opposite edge of the groove.

9. A unit as claimed in any one of claims 3 to 6, wherein the facing surfaces of the guides and the engaging end surfaces of the side wall are complementarily sloped.

10. A unit as claimed in any one of claims 4 to 6, or claim 8, wherein the base at the outer side of the groove is raised relative to the base at the inner side thereof.

11. A unit as claimed in claim 7, wherein the respective upper surfaces of the four sides of a single unit, or a composite unit, are formed with a continuous lip to engage with a complementary lip in a depending flange of a cover engageable with the sides of the unit.

12. A unit as claimed in claim 11, wherein upstanding tubular columns are provided on the base, the columns having holes to receive self-tapping screws passing through holes in the cover to secure it to the remainder of the unit.

13. A unit as claimed in claim 11, wherein upstanding tubular columns are provided on the base, the columns having holes to receive special screws requiring only a 90" turn once passed through holes in the cover, to secure the cover to the remainder of the unit.

14. A unit as claimed in claim 5 or claim 6, wherein each member has a finger grip part at its one end to facilitate disengagement from the units.

15. An electrical consumer unit substantially as hereinbefore described with reference to and as shown in the accompanying drawings.