GB2441797A

GB2441797A - Cable joint housing for distribution cabinet

Info

Publication number: GB2441797A
Application number: GB0618102A
Authority: GB
Inventors: Keith John Coates; Kirby Sheppard
Original assignee: RIDER COMMS Ltd
Current assignee: RIDER COMMS Ltd
Priority date: 2006-09-14
Filing date: 2006-09-14
Publication date: 2008-03-19
Anticipated expiration: 2026-09-14
Also published as: GB2441797B; GB0618102D0

Abstract

A cable joint assembly for fitting within an above-ground distribution cabinet comprises an enclosure 2 adapted to be suspended within the cabinet and having cable ports (18, fig 2) extending through a bottom wall of the enclosure and a door (10, fig 2) providing access to the interior of the enclosure from the front. The assembly has hooks 5 so that it can be hooked over the top of the backboard 3 within a power distribution cabinet and then appropriately secured, e.g. by screwing through holes 6 in flanges 4, to the backboard. The assembly is pre-wired prior to installation in the cabinet so that all that is required, after fitting of the enclosure within the cabinet, is termination of the incoming and outgoing cables. The assembly may also be used with fibre optic cables.

Description

2441797

M&C Folio No P53879GB 1

Cable Joint Assemblies

This invention relates to cable joint assemblies for installation within above-ground distribution cabinets.

Known cable joint assemblies for installation within above-ground 609 power distribution cabinets comprise up to three individual plastic enclosures that require to be screwed to a wooden backboard within the cabinet, and the complete installation procedure is lengthy and complex. The enclosures must be screwed to the backboard while the backboard is in the cabinet as, after the enclosures have been fitted to the backboard, the holes for securing the backboard within the cabinet are covered up by the enclosures. On the distribution side two separate plastic boxes must be screwed together. Back plates must then be drilled to accept electrical components that are then attached prior to the back panels being fitted into the enclosures, care being taken at this point to ensure that the correctly rated fuses and wires are used as incorrect selection could result is overheating and melting of the cables prior to the fuses burning out Electrical continuity is then maintained between the distribution unit and the back panels by means of a series of yellow green wires each with ring crimps on its ends. During all this time the enclosures may be exposed to the elements which is clearly undesirable from the point of view of safety and connection integrity. The units are then ready for the attachment of the input and output cables. If telecommunications is also to be incorporated into the cabinet, a separate dome enclosure must be fitted in the bottom of the cabinet to hold the appropriate cables for cross connection.

Such known cable joint assemblies are disadvantageous for a number of reasons. Firstly, whichever variant of the above ground power distribution cabinet is used, a minimum of two plastic enclosures is required and these have to be mechanically and electrically fixed together by fixings that provide points of weakness. This can result in failure in the earth bonding by multiple bonding wires and in failure of the ingress protection between units, doors, gaskets and glands.

M&C Folio No P53879GB 2

Furthermore each enclosure includes a door that is held in place by plastic screws that are time-consuming to install and are prone to snapping (which are typically not replaced in the field leading to moisture entering the unit). The door can also become brittle as the plastic degrades over time. The installation also requires extensive roadside preparation involving internal wiring, as well as external jointing and jointing between units, and this can give rise to errors in the field whilst installation is being carried out in all weathers and with traffic running past.

It is an object of the invention to provide a novel cable joint assembly for fitting within an above-ground distribution cabinet that overcomes some of the disadvantages of such known cable joint assemblies.

According to the present invention there is provided a cable joint assembly for fitting within an above-ground distribution cabinet, the assembly comprising an enclosure adapted to be suspended within the cabinet, the enclosure having cable ports extending through a bottom wall of the enclosure and a door providing access to the interior of the enclosure from the front.

Such an assembly can be constructed so that it can be hooked over the top of the backboard within a 609 power distribution cabinet and then appropriately secured, as by screwing, to the backboard. This enables the assembly to be pre-wired according to the requirements of the appropriate roadside marker prior to installation in the cabinet so that all that is required, after fitting of the enclosure within the cabinet, is termination of the incoming and outgoing cables. This renders installation of the assembly within the cabinet particularly straightforward, substantially decreasing the extent of roadside preparation required and generally increasing the reliability of the internal winding by virtue of the fact that this is carried out under controlled conditions in the factoiy.

Furthermore allowance can be made for incorporating telecommunications into the unit by way of an EMC shielded enclosure within the unit which removes the need for an additional dome / wiring. Installation can be done safe in the knowledge that each

M&C Folio No P53879GB 3

assembly is individually serial numbered so as to relate directly to a Certificate of Conformity and a relevant Test Certificate.

In a preferred embodiment of the invention the door is detachable from the rest of the enclosure, and is preferably openable by pivoting relative to a vertical edge of the enclosure. Conveniently the door is provided with a lift-off hinge assembly enabling pivoting of the door relative to the vertical edge of the enclosure and detachment of the door as a whole from the enclosure. Furthermore the door may be provided with a latching mechanism for latching the door in a closed position, the latching mechanism comprising a latching pawl mounted on a rotatable shaft such that the latching pawl is brought from a reversed position to a forward position on rotation of the shaft to effect compression latching engagement with an edge portion of the enclosure. The latching mechanism may be operable by a quick-release handle. This enables access to be gained to the electrical equipment quickly and with minimum exposure of the engineer to the environment.

The enclosure may be provided with a back mounting panel adapted to have at least one electrical component mounted thereon. In a development of the invention the back mounting panel is double-sided with each of its sides being adapted to have at least one electrical component mounted thereon.

The assembly is adaptable to different applications, and may be used for the connection of electrical power distribution, or for optical fibre termination. For example, the assembly may in the form of a lull depth unit or a half depth unit. The full depth unit can be used for either full power distribution incorporating telecommunications, or solely for copper distribution incorporating local and distribution sides. Using a modular design it is possible to convert a standard unit to house any application required to fit in the standard 609 cabinet whilst ensuring high build quality and high standards of ingress protection.

M&C Folio No P53879GB 4

In a variant embodiment of the invention the enclosure comprises an outer frame adapted to be suspended from the top of a backboard within the cabinet and to be secured to the backboard, and an inner housing held within the frame.

In order that the invention may be more fully understood, a preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view showing the manner in which the enclosure is installed within a power distribution cabinet;

Figure 2 is a further perspective view of the enclosure before installation of the electrical equipment;

Figure 3 is a front view of four such enclosures of different types after installation of the electrical equipment and with the door open;

Figure 4 is a diagrammatic view showing a quick-release handle of the enclosure; and

Figure 5 is a perspective view of an enclosure for a double unit before installation of the electrical equipment.

A preferred embodiment of cable joint assembly for fitting within an above-ground 609 power distribution cabinet in accordance with the invention will now be described by way of example.

As shown in Figure 1, the cable joint assembly comprises an enclosure 2 designed to be secured within the cabinet by being attached to a standard backboard 3 (1/2" Marine ply) pre-installed within the cabinet. To this end the upper part of the enclosure 2 is provided with two hooks 5 by means of which the enclosure 2 may be suspended from the top of the backboard 3 within the cabinet, the hooks 5 being provided with connection holes by means of which the enclosure 2 may be secured by wood screws to

M&C Folio No P53879GB 5

the backboard 3. Furthermore the lower part of the enclosure 2 is provided with two flanges 4 provided with connection holes 6 by means of which the enclosure 2 may be secured by wood screws to the backboard 3 within the cabinet. The hooks 5 aid installation within the cabinet during single person operation allowing the unit to be hooked into position before being screwed in place. In the case of a double depth enclosure 2' as shown in Figure 5, the backboard may be removed and the enclosure 2' hooked over a top bar within the cabinet and then secured in position by two M8 hex head bolts to a bottom bar within the cabinet. Where two enclosures 2 are to be installed within a cabinet, the hooks 5 of each enclosure 2 may hook over the backboard so as to mount the enclosures 2 side by side and allow any other equipment required to be installed to the rear of the backboard. Alternately the enclosures 2 may be mounted either side of the backboard, the hooks being adapted to accommodate back to back mounting.

The enclosure 2 is installed within the cabinet in the manner described above after the enclosure has been pre-fitted with the required electrical equipment and glands for accommodating die ingoing and outgoing cables to be connected to the electrical equipment within the enclosure 2. Each such enclosure 2 is supplied to the installation engineer individually serial numbered and associated directly to a Certificate of Conformity and relevant test certificate. The enclosure 2 is a single piece fully welded construction manufactured from aluminium so that the installation engineer has a minimum weight to carry around, and finished in a first coat of Alocrom 1200 to prevent galvanic processes to defence standards prior to application of a final durable grey finish powder coat The enclosure 2 has a minimum of parts and openings to prevent electrical and ingress failure and incorporates an integral back-mounting panel to ensure continuity.

As shown in Figure 2, the enclosure 2 has a door 10 provided with a viewing window 11 manufactured from very high impact polycarbonate such that it will not break, smash or produce sharp edges and is self-extinguishing. Furthermore the door 10 is connected to the enclosure 2 by a lift-off hinge assembly comprising three hinges 12 which are such as to enable the door 10 to be pivoted into the open position shown in Figure 2, as

M&C Folio No P53879GB

6

well as to enable the door 10 to be detached from the rest of the enclosure 2 by pulling the door 10 upwardly to detach the two parts of each hinge 12 from one another, so as to allow greater access to the inside of the enclosure 2 for servicing the electrical equipment. Furthermore the door 10 may be hinged from the position shown in Figure 2 to the closed position in which it compresses a bubble gasket 14 surrounding the opening of the enclosure 2 to provide the required sealing from the atmosphere, the door 10 then being latched in the closed position by two quick release compression latches (not shown in Figure 2, but described in more detail below with reference to Figure 4).

Furthermore a bottom wall 15 of the enclosure 2 is provided with a rectangular cut out 16 and a blanking plate 17 having a series of circular apertures 18 therein extending over the cut out 16 and secured to the bottom wall 15 by screws. The enclosure 2 is supplied with cable glands fitted within the apertures 18, such as a single CW25 gland for cable input and up to five CW25 glands for cable output. CW25 glands are suitable for use with external armoured cable and provide a cable range of 22.5mm to 27.5mm, the glands being preferably such as to provide an ingress protection rating IP66 and to be RoHS Directive 2002/95/EC compliant, with an overall size of 259 width x 280 deep x 783 high. The weight of the entire enclosure 2 pre-fitted with electrical equipment is typically of the order of 8 Kgs, and all processes and materials used comply with Highways Agency specification TR1100 issue C March 2003.

In the case of a double depth enclosure 2' as shown in Figure 5, the enclosure 2' is provided with two doors 30 and 31 generally constructed and arranged to be hinged between open and closed positions in the same manner as the door 10 of the embodiment of Figures 1 and 2 and a bottom wall provided with a blanking plate 32 having a series of circular apertures therein. In addition brackets 33 are provided for supporting a mounting plate (not shown) centrally within the enclosure 2'.

Figure 3 shows four separate enclosures fitted with different types of equipment and cables. In each case the enclosure is shown ready to be installed within a cabinet. The equipment installed within the enclosure may include optical fibre splicing and management equipment, copper communications equipment and printed circuit boards

M&C Folio No P53879GB

7

(PCB's) or power distribution equipment and personnel safety devices, depending on the particular requirements. In the case of the double unit, electrical connections between the enclosures may be achieved by running cables around the mounting plate located centrally within the enclosure with relevant edge protection being installed. When 2 PCB's are used (copper above ground with local and longitudinal sides) cross connection between the two boards may be by means of banks of connectors on the rear of the boards, such connectors being internal to the unit so that they are not accessed by the installation engineer unless one of the boards requires replacement.

The only action to be taken by the installation engineer after the installation of the enclosure within the cabinet is the threading of the cables through the glands and the stripping of the ends of the individual wires within the cables prior to their being secured within the termination blocks in order to complete the electrical connection (or analogous connection procedures in the case of optical fibre termination).

The ready fitted unit fits directly into a 609 cabinet, thereby saving a minimum of half an hour of installation time. After installation within the cabinet, access to the electrical equipment within the enclosure can be gained quickly and easily by release of the quick release latches, and if necessary the removal of the door to allow full access. Two different sizes of unit are available for installation within such a cabinet, namely a full depth unit and a half depth unit. Furthermore, because each unit has a removable blanking plate and a removable back plate, the same enclosure can be used for both power distribution and optical fibre termination. The full size unit can be used either for power distribution incorporating telecommunications control or solely for power distribution, with local and distribution sides.

The unit may be adapted for use as an above ground optical fibre termination box requiring no special tooling for installation, enabling through splicing of longitudinal cables on the transmission side of the joint, with splice through connections to local equipment using 24 fibre cable by way of the local side of the joint. The joint uses splice cassette facilities for location fibre manifolds on the splice cassette support assembly, and is capable of being fitted with the transmission side only or with both

M&C Folio No P53879GB 8

transmission and local sides. The individual of five individually hinged splicing trays shrinkable splice protectors.

fibres can be broken out and routed to any each accommodating up to twelve heat

Figure 4 is a sectional view of the edge of the enclosure door 10 (or 30 or 31 in the case of the embodiment of Figure S) showing one of the compression latches 20 comprising a shaft 20A extending through a hole in the door and being secured thereto by a mounting nut 21 and mounting lockwasher 22 provided on a screwthreaded portion of a sleeve 23, the sleeve 23 being provided with a pivotable and turnable handle 24 on the outside of the door. The shaft 20A is screwthreaded and has a pawl 25 mounted thereon by a jam nut 26 and lockwasher 27 and a pawl retainer 28. In order to open the latch 20 the handle 24 from the closed position shown in the figure, the handle 24 must be lifted to displace the shaft 20A axially (approximately 8- 10mm) and then turned to cause swivelling of the pawl 25 to a position enabling the door to be opened. Once the pressure is released by the cam action of the handle 24 this allows the pawl 25 to be turned through 90 degrees, thus clearing the flange 29 on the inside of the enclosure 2 to allow the door 10 to be opened. This cam action ensures a very tight fit on the edge seal of the enclosure 2 to provide a good ip rating.

M&C Folio No P53879GB

9

Claims

1. A cable joint assembly for fitting within an above-ground distribution cabinet, the assembly comprising an enclosure adapted to be suspended within the cabinet, the enclosure having cable ports extending through a bottom wall of the enclosure and a door providing access to the interior of the enclosure from the front.

2. A cable joint assembly according to claim 1, wherein an upper part of the enclosure is provided with two hooks by means of which the enclosure may be suspended within the cabinet.

3. A cable joint assembly according to claim 1 or 2, wherein a lower part of the enclosure is provided with at least two connection holes by means of which the enclosure may be secured within the cabinet.

4. A cable joint assembly according to claim 1, 2 or 3, wherein the door is detachable from the rest of the enclosure.

5. A cable joint assembly according to any preceding claim, wherein the door is openable by pivoting relative to a vertical edge of the enclosure.

6. A cable joint assembly according to claims 4 and 5, wherein the door is provided with a lift-off hinge assembly enabling pivoting of the door relative to the vertical edge of the enclosure and detachment of the door as a whole fiom the enclosure.

7. A cable joint assembly according to any preceding claim, wherein the door is provided with a latching mechanism for latching the door in a closed position.

8. A cable joint assembly according to claim 7, wherein the latching mechanism comprises a latching pawl mounted on a rotatable shaft such that the latching pawl is brought from a reversed position to a forward position on rotation of the shaft to effect latching engagement with an edge portion of the enclosure.

M&C Folio No P53879GB

10

9. A cable joint assembly according to claim 7 or 8, wherein the latching mechanism is operable by a quick-release handle.

10. A cable joint assembly according to any preceding claim, wherein the enclosure is provided with a back mounting panel adapted to have at least one electrical component mounted thereon.

11. A cable joint assembly according to claim 10, wherein the back mounting panel is double-sided with each of its sides being adapted to have at least one electrical component mounted thereon.

12. A cable joint assembly according to any preceding claim, wherein the enclosure comprises an outer frame adapted to be suspended from the top of a backboard within the cabinet and to be secured to the backboard, and an inner housing held within the frame.

13. A cable joint assembly according to any preceding claim, wherein the cable ports are provided with glands for accommodating cables to be connected to electrical components within the enclosure.

14. A cable joint assembly according to any preceding claim, wherein the door is provided with a viewing window.

15. A cablc joint assembly according to any preceding claim, wherein the door is provided with screws for securing it to the rest of the enclosure.

15. A cable joint assembly according to any preceding claim, wherein a sealing gasket is provided for sealing between the door and the rest of the enclosure.

16. A cable joint assembly according to any preceding claim, for fitting within an power distribution cabinet.

M&C Folio No P53879GB

11

17. A cable joint assembly according to any preceding claim, for fitting within an optical fibre termination cabinet.

18. A cable joint assembly substantially as hereinbefore described with reference to the accompanying drawings.

19. An above-ground distribution cabinet incorporating a cable joint assembly according to any preceding claim.