GB2452740A

GB2452740A - Underground electrical connection apparatus having a cover trapping a pocket of air

Info

Publication number: GB2452740A
Application number: GB0717827A
Authority: GB
Inventors: Derek Jones
Original assignee: TOBERMORY Ltd
Current assignee: TOBERMORY Ltd
Priority date: 2007-09-12
Filing date: 2007-09-12
Publication date: 2009-03-18
Also published as: GB0717827D0

Abstract

Apparatus for making underground electrical connections comprising a cover 40 having an open bottom and forms a chamber, similar to a bell-jar, which is placed over an electrical connection 34; the bottom 50 of the cover 40 is below the level of the electrical connection 34 and a pocket of air trapped within chamber 40 prevents ground water from rising into the cover during flooding. The electrical connection unit 34 is preferably supported within a hole by mounting bracket 32 comprising a mounting board 38 and mounting rails 36 which may be cast into side walls of housing 12. The cover 40 may form an external cover surface which pedestrians can walk on (118, fig.3); alternatively a separate outer cover 18 may be provided and the inner cover 40 may be prevented from upward movement by retaining rod 26 secured across the top of the cover and secured in recess 25 in housing 12. The electrical connection unit may connect mains electricity supply to a bus shelter or street-side advertising equipment.

Description

UNDERGROUND ELECTRICAL CONNECTION APPARATUS

Field of the Invention

The invention relates to underground electrical connection apparatus and particularly to underground electrical connection apparatus for providing an electrical connection between a mains electricity supply and street-side electricity consuming equipment.

Background to the Invention

It is known to provide street-side electricity consuming equipment that needs an electricity supply from a mains electricity source. Examples of such equipment include advertising equipment, lighting and display equipment incorporated in bus shelters, coin operated toilet facilities and parking ticket-issuing equipment.

One form of electrical connection apparatus used for street-side installations comprises a housing that is secured to the pavement above ground with a mains supply cable running up through the pavement into it. The mains supply cable is connected to an electrical connection unit within the housing. Suitable cabling is then run from the connection unit to street-side electricity consuming equipment as required. One disadvantage of this sort of connection apparatus is that if the electricity consuming equipment is later removed, the above ground connection apparatus has to be left in place to provide a termination for the mains supply cable, or the pavement needs to be dug up to allow termination of the mains cable underground.

Another form of electrical connection apparatus for street-side installations is provided underground. This has the advantage that if the electricity consuming equipment is later removed, there is no above ground installation left behind.

However, with an underground connection apparatus there is the problem of sealing the electrical connection unit against flooding by ground water. For this reason known underground electrical connection apparatus are provided with seals, which makes such apparatus more complicated and expensive to manufacture. It also calls for care in the making and remaking of installations to ensure that the seals are properly made. In practice it has been found that the seals in such apparatus do not always work particularly well.

Summary of the Invention

The invention provides an apparatus for making underground electrical connections, said apparatus comprising housing means for installation in a hole in the ground, mounting means in said housing means to which, in use, an electrical connection unit is mounted and cover means, said cover means defining a chamber having an opening arranged such that the cover means can be placed over said mounting means such that an electrical connection unit mounted thereon is received in the chamber and protected from groundwater by air trapped in said chamber.

The invention also includes apparatus for making underground electrical connections, said apparatus comprising a housing to be installed in a hole in the ground, an electrical connection unit housed in said housing and a cover, said cover defining an open chamber having an opening arranged such that the cover can be placed over the electrical connection unit with the electrical connection unit received in said open chamber and such that rising water in said housing is prevented from reaching said electrical connection unit by air trapped in said open chamber between the cover and surface of the rising water.

The invention also includes a method of making an underground electrical connection, said method comprising: providing a mounting in a hole in the ground and an electrical connection unit mounted to said mounting; connecting mains electricity supply cabling with said electrical connection unit; connecting cabling between said electrical connection unit and street side electricity consuming equipment; and placing a cover defining an open chamber over said electrical connection unit and said connections made to it such that said electrical connection unit and said connections are within said open chamber and protected against water rising in said hole by atmospheric air contained in said chamber.

Brief Description of the Drawing

In order that the invention may be well understood, some embodiments thereof, which are given by way of example only, will now be described with reference to the drawings in which: Figure 1; is an exploded perspective view of an underground electrical connection apparatus; Figure 2 is a section on line 11-Il in Figure 1 showing the apparatus located in a hole in the ground made through a pavement; Figure 3 is an exploded perspective view of another underground electrical connection apparatus; and Figure 4 is a section on line EV-IV in Figure 3.

Detailed Description of the illustrated Embodiments Referring to Figures 1 and 2, an underground electrical connection apparatus 10 comprises a generally rectangular housing 12 that is fitted at its upper end with a cover locating frame 14. The housing 12 is a cast concrete rectangular tube that is open at each end. The cover locating frame 14 comprises four elongate pressed steel members cast end-to-end into the concrete of the housing 12 to provide a substantially continuous rectangular steel frame extending around the periphery of the upper end of the housing. The cover locating frame 14 defines a recessed ledge 16 on which a top cover 18 seats and a rectangular rim 20 projecting upwardly from the ledge 16. Each member of the cover locating frame 14 has an inwardly projecting tab 22 located midway along its length and a generally U-shaped metal strip 24 fitted to the underside of the tab. The metal strips 24 are preferably joined to the tabs 22 by welding. As described in more detail below, the metal strips 24 cooperate with the underside of the tabs 22 to define respective mounting recesses 25 for a retaining bar 26.

The top cover 18 is a rectangular cast steel plate shaped to seat on the ledge 16 within the rim 20 so as to completely close the upper end of the housing 12. In use, the housing is installed in a hole made through a pavement 28 (Figure 2) such that the upper edge of the rim 20 and the upper surface of the top cover 18 are generally level with the pavement. The upper surface of the top cover 18 is provided with formations to provide grip for pedestrians walking over it. Preferably, the cover 18 is provided with keyhole openings 31 to receive the T-shaped heads of respective lifting bars, which are tools that will be well known to those skilled in the art.

As best seen in Figure 2, the housing 12 is provided with a mounting 32 for an electrical connection unit 34. The mounting 32 comprises a pair of generally L-shaped sheet metal rails 36 that have their ends cast into opposite sides of the housing 12. The rails 36 are disposed in parallel spaced apart relationship. The mounting 32 also includes a board 38 that is secured to the rails 36 such that it lies generally parallel to the top cover 18. The board 38 is preferably made of wood so that it is easy to secure the electrical connection unit 34, cable ties and other equipment to it.

The underground electrical connection apparatus 10 includes an inner cover 40 for the electrical connection unit 34. The inner cover 40 is preferably a generally rectangular plastics bowl made by a vacuum forming process and comprises a transverse upper wall 42 and a depending wall 44 that extends continuously around the periphery of the upper wall. The upper wall 42 is formed with two arcuate section grooves 46 that extend at right angles to one another and intersect at the centre of the upper wall.

Each groove 46 extends from one side of the upper wall 42 to the other for receiving the retaining bar 26.

Referring to Figure 1, the rails 36 have a cut-out 48 adjacent the point at which they enter the walls of the housing 12 so that there is a gap between the upper portion of each rail and the adjacent wall of the housing. The inner cover 40 seats in the cut-outs 48 so that the electrical connection unit 34 and mounting board 38 are located above the free edge 50 of the depending wall 44 within a chamber 52 defined by the inner cover.

In use, the housing 12 is fitted into a hole dug through the pavement 28. The space 54 between the upstanding sides of the hole and the housing 12 may be filled with sand or cement to firmly locate the housing in the hole. A single phase mains electricity supply cable (indicated schematically by line 56) enters the housing 12 through its open lower end and is connected to the electrical connection unit 34. When street-side electricity equipment (not shown) is installed, an electrical cable (indicated schematically by line 58) is run from the equipment into the housing 12 through the open lower end of the housing and connected to the electrical connection unit 34. The inner cover 40 is then lowered into the housing 12 through its open upper end until respective portions of the free edge 50 of the depending wall 44 seat on the cut-outs 48. When in this position, the electrical connection unit 34 and the electrical connections made to it are contained in the chamber 52 above the level of the free edge 50 of the depending wall 44. The retaining bar 26 is then fitted into one of the pairs of mounting recesses 25. In this position, it will lie in one of the two grooves 46 and prevent movement of the inner cover, particularly upward movement, relative to the housing 12.

During wet weather conditions, the electrical connection unit 34 and the electrical connections made to it are protected against any water ingress from above by the top cover 18 and inner cover 40. If there is a build up of ground water that generates a rising water level within the housing 12, it is prevented from reaching the electrical connection unit 34 and the electrical connections made to it by the pocket of air contained within the chamber 52. The pocket of air cannot be displaced since it has no escape route from the inner cover 40 and so it prevents the ground water from rising significantly above the level of the edge 50 of the depending wall 44.

Referring to Figures 3 and 4 another underground electrical connection apparatus 100 comprises the same components as the underground electrical connection apparatus 10, except that it does not have any mounting recesses 25, a retaining rod 26 or an inner cover 40. To avoid repetition of description, components of the apparatus 100 that correspond to components so the apparatus 10 are indicated in Figures 3 and 4 by the same reference numerals incremented by 100.

The top cover 118 comprises an integral depending wall 144 that defines a chamber 152 in which the electrical connection unit 134 and electrical connections made to it are housed. As with the underground electrical connection apparatus 10, the electrical connection unit 134 and electrical connections made to it are positioned above the free edge 150 of the depending waIl 144 so that they are protected against rising ground water in the housing 12 by the pocket of air contained in the chamber 152, which has no means of escape from the chamber should the water level reach the free edge 150 of the depending wall.

Figure 4 shows a limb 160 of the cover locating frame 114 that is embedded in the housing 112 during casting of the concrete housing.

It will be appreciated that the underground electrical connection apparatus 10, 100 provide the possibility of underground electrical connections that are effectively waterproofed without the use of seals or otherwise closed spaces. Accordingly, the manufacture and installation of the apparatus is made simpler and more economic than known apparatus that requires the use of seals and/or close fitting parts.

It will be understood that the apparatus 100 can be made more economically than the apparatus 10 since it does not have a separate inner cover or retaining means for such a cover. Instead the chamber 152 in which the electrical connection unit is kept dry is formed by the top cover 118 and an integral wall 144 depending from it. A retaining means should not be needed as the weight of the top cover should be sufficient to resist any up thrust generated by rising water in the housing 12.

The provision of a separate inner cover 40 does, however, provide advantages to having the chamber defined by the top cover and parts connected to it. If the chamber is defmed by the top cover and parts connected to it, there is a risk that removing the top cover and so removing the resistance provided by the air pocket in the chamber 152 will result in water rising within the housing 112 and flooding the electrical connection unit 134 and any electrical connection made to it. Where a separate inner cover is used, as shown in Figures 1 and 2, it is possible to remove the top cover and inspect the water level within the housing 12 around the inner cover. If the water level is above the level of the free (lower) edge of the inner cover, steps can be taken to remove the water prior to removing the inner cover so that the electrical connection unit and any connections made to it are not flooded.

It will be appreciated that while the chambers 52, 152 in the illustrated embodiments are generally rectangular, this is not essential. For example, the depending wall 144 could be annular. The chamber can be any suitable shape or size and formed from any convenient material. All that is needed is that the part or parts defining the chamber should have an opening that allows them to be placed relative to the electrical connection unit mounting such that the electrical connection unit is covered from above by a chamber such that the air contained in the chamber cannot escape and will prevent rising water entering the chamber and flooding the electrical connection unit and any electrical connection made to it.

It will be understood that although the apparatus 10, 100 are shown having just one electrical connection unit, multiple electrical connection units may be provided and the parts of the apparatus sized accordingly. The electrical connection unit(s) may take any form for making an electrical connection between a mains electricity supply and cabling leading to street-side electricity consuming equipment.

It will be appreciated that while the housing 12 is conveniently a cast concrete construction, this is not essential. The housing could, for example, be a cast or fabricated metal construction.

It will be understood that while the cover 18, 118 may conveniently be made as a metal casting, it could instead be made of an engineering plastic or, in the case of the cover 18, it could be a concrete slab in a steel frame.

It will be understood that while the inner cover can conveniently be secured in the housing by a retaining bar as illustrated in Figures 1 and 2, it could instead be provided with formations, including resilient clips, by which it could interengage parts on the housing or mounting. Alternatively, the inner cover could be made sufficiently heavy for no securing to be necessary.

It will be understood that the housing could be fabricated on site, for example using bricks and cement, and that the mounting for the electrical connection unit could be fixed to the brick walls of the housing or embedded in those walls as a part of the building process.

Claims

Claims 1. Apparatus for making underground electrical connections, said apparatus comprising housing means for installation in a hole in the ground, mounting means in said housing means to which, in use, an electrical connection unit is mounted and cover means, said cover means defming a chamber having an opening arranged such that the cover means can be placed over said mounting means such that an electrical connection unit mounted thereon is received in the chamber and protected from groundwater by air trapped in said chamber.
2. Apparatus for making underground electrical connections as claimed in claim 1, wherein said cover means comprises a transverse wall having a periphery and a wall depending from and extending around said periphery.
3. Apparatus for making underground electrical connections as claimed in claim 2, wherein a free end of said depending wall defines said opening.
4. Apparatus for making underground electrical connections as claimed in claim 3, wherein said free end seats on said mounting means.
5. Apparatus for making underground electrical connections as claimed in any one of the preceding claims, wherein said cover means is an inner cover and further comprising a second cover means locatable at an upper end of said housing means for closing said upper end of the housing means.
6. Apparatus for making underground electrical connections as claimed in claim 5, wherein said inner cover is a plastics moulding.
7. Apparatus for making underground electrical connections as claimed in claim 5 or 6, further comprising securing means for securing said inner cover in said housing means such that at least upward movement of the inner cover with respect to said housing means is substantially prevented.
8. Apparatus for making underground electrical connections as claimed in claim 7, wherein said securing means comprises a retainer bar received in a formation on said inner cover and opposed mountings fixed with respect to said housing.
9. Apparatus for making underground electrical connections as claimed in any one of claims I to 4, wherein said cover means is locatable at an upper end of the housing means for closing said upper end of the housing means.
10. Apparatus for making underground electrical connections as claimed in any one of the preceding claims, wherein said housing means is a generally tubular member.
ii. Apparatus for making underground electrical connections as claimed in any one of the preceding claims, wherein said housing means is a concrete casting.
12. Apparatus for making underground electrical connections as claimed in claim 11, wherein said mounting means comprises at least one member cast into the concrete casting.
13. Apparatus for making underground electrical connections, said apparatus comprising a housing to be installed in a hole in the ground, an electrical connection unit housed in said housing and a cover, said cover defining an open chamber having an opening arranged such that the cover can be placed over the electrical connection unit with the electrical connection unit received in said open chamber and such that rising water in said housing is prevented from reaching said electrical connection unit by air trapped in said open chamber between the cover and surface of the rising water.
14. Apparatus for making underground electrical connections as claimed in claim 13, wherein said cover comprises a generally transverse wall and a wall depending from said transverse wall, a free end of said depending wall defining an opening to said chamber.
15. Apparatus for making underground electrical connections as claimed in claim 14, further comprising a mounting for said electrical connection unit fixed to said housing and wherein said free end rests on said mounting when said cover is placed over said electrical connection unit.
16. Apparatus for making underground electrical connections as claimed in claim 14, wherein said depending wall is suspended within said housing.
17. Apparatus for making underground electrical connections as claimed in any one of claims 13 to 16, wherein said housing is a generally tubular member and said mounting comprises at least one member extending between opposite side portions of the tubular member.
18. Apparatus for making underground electrical connections as claimed in claim 17, wherein the or each member has respective ends embedded in said side portions of the housing.
19. Apparatus for making underground electrical connections as claimed in claim 17 or 18, wherein said tubular member is made of concrete.
20. Apparatus for making underground electrical connections as claimed in any one of claims 13 to 19, wherein said cover is an inner cover locatable within said housing and further comprising a second cover locatable on the housing so as to close the housing against entry from above.
21. Apparatus for making underground electrical connections as claimed in claim 20, wherein, in use, said second cover provides a walking surface for pedestrians.
22. Apparatus for making underground electrical connections as claimed in claim or 21, wherein said inner cover is releasably securable in said housing such that at least upward movement of the inner cover relative to the housing is at least substantially prevented.
23. Apparatus for making underground electrical connections as claimed in claim 20, 21 or 22, wherein said inner cover is a plastic moulding.
24 Apparatus for making underground electrical connections as claimed in any one of claims 13 to 19 wherein said cover is for closing said housing against entry from above.
25. Apparatus as claimed in claim 24, wherein, in use, said cover provides a walking surface for pedestrians.
26. An installation comprising an apparatus for making underground electrical connections as claimed in any one of the preceding claims provided in a hole in the ground, mains electricity supply cabling connected to an electrical connection unit housed in said chamber and cabling connecting between said electrical connection unit and street side electricity consuming equipment.
27. A method of making an underground electrical connection, said method comprising: providing a mounting in a hole in the ground and an electrical connection unit mounted to said mounting; connecting mains electricity supply cabling with said electrical connection unit; connecting cabling between said electrical connection unit and Street side electricity consuming equipment; and placing a cover defining an open chamber over said electrical connection unit and said connections made to it such that said electrical connection unit and said connections are within said open chamber and protected against water rising in said hole by atmospheric air contained in said chamber.
28. A method of making an underground electrical connection as claimed in claim 27, comprising placing said cover within said hole such that it is underground.
29. A method of making underground electrical connections as claimed in claim 28, comprising securing said over said electrical connection unit such that the cover is at least substantially prevented from upward movement relative to the electrical connection unit.

II
30. A method of making underground electrical connections as claimed in claim 28 or 29, comprising providing a second cover over said cover, said second cover being located in the region of the upper end of said hole.
31. A method as claimed in any one of claims 27 to 30, wherein said electricity consuming equipment is at least one of electricity consuming equipment in a bus shelter and streetside advertising equipment.
32. Apparatus for making underground electrical connections substantially as herein described with reference to Figures 1 and 2 or 3 and 4.
33. A method of making an underground electrical connection substantially as herein described with reference to Figures 1 and 2 or 3 and 4.