GB2444526A

GB2444526A - Contact for electrical cut-out

Info

Publication number: GB2444526A
Application number: GB0617818A
Authority: GB
Inventors: Nigel Barrett
Original assignee: Lucy & Co Ltd W
Current assignee: Lucy & Co Ltd W
Priority date: 2006-09-11
Filing date: 2006-09-11
Publication date: 2008-06-11
Anticipated expiration: 2026-09-11
Also published as: GB2444526B; GB0617818D0

Abstract

An electrical cut-out 14a suitable for pole-top use in an electrical distribution system comprises a housing In which is mounted a pair of internal conductors 42, 44, each terminated at one end with a cable connection and terminated at the other end adjacent an aperture in the housing, and a link unit 34 having an insulating handle 36 and a link conductor 50, the link unit 34 being attachable to the housing such that at least the ends of the link conductor 50 project through the aperture and make contact with the internal conductors 42, 44, thereby to bridge them, wherein at least one of the internal conductors 42, 44 comprises an elongate conductive strip having a width greater than Its thickness and having at least one bend 46 therein In the plane defined by the thickness directions of the strip adjacent the bend 46. It is preferred that the bend 46 is about 90{. It is also preferred that both the internal conductors 42, 44 are shaped in this way. The internal conductors 42, 44 can comprise a flat plate that was previously subjected to a bending process. In this way, if no other bends are required, the conductors 42, 44 can be fabricated from a rectangular sheet of a suitable metallic material with minimal wastage.

Description

Contact for Electrical Cut-Out

FIELD OF THE INVENTION

The present invention relates to a contact for an electrical cut-out.

BACKGROUND ART

Electrical cut-outs are required in a variety of situations in order to allow for electrical isolation of a specific circuit or a specific length of cable. Generally, they comprise a housing in which is mounted a pair of internal conductors, each terminated at one end with a cable connection and terminated at the other end * adjacent an aperture in the housing. A link unit is also provided, which has an insulating handle and a link conductor, and which can be attached to the housing **** *... such that at least the ends of the link conductor project through the aperture and make contact with the internal conductors, to bridge them. S...

SUMMARY OF THE INVENTION

The cables used in electrical distribution systems are usually of a heavy gauge and are not apt to be bend into intricate shapes. Accordingly, it would be advantageous for the cut-out to be a suitable shape in order to accept the cables in the direction in which they are likely to arrive.

One common context is a pole-top cut-out. A cut-out may need to be placed in an elevated location in order to discourage access by those not qualified to do so, and is therefore fitted to a pole. The cables therefore need to run up the pole to the cut-out, and then down the pole in order to return to the conduit (or the like) along which they arrived. Thus, the arriving and departing cables present themseives to the cut-out alongside each other. This means that the internal conductors have, to date, been designed in an L-configuration so that an in-line connection may be made with the cables and with the link connector; the right angles in each of the two internal connectors together make up the necessary 1800 turn from one cable to the next. This also allows both cable entry ports to be directed in a downwards direction, thereby assisting in protecting the interior from environmental influences.

The present invention therefore provides an electrical cut-out, comprising a housing in which is mounted a pair of internal conductors, each terminated at one end with a cable connection and terminated at the other end adjacent an aperture in the housing, and a link unit having an insulating handle and a link conductor, the link unit being attachable to the housing such that at least the ends of the link conductor project through the aperture and make contact with the internal conductors thereby to bridge them, wherein at least one of the internal conductors comprises an elongate conductive strip having a width greater than its thickness and having at least one bend therein in the plane : defined by the thickness directions of the strip adjacent the bend. S... * S *SS*

It is preferred that the bend is about 900. It is also preferred that both *S..

: the internal conductors are shaped in this way. Two such 900 bends will of *. course provide the necessary 1800 bend as discussed above.

** The internal conductor or conductors can comprise a flat plate that was *.! previously subjected to a bending process. In this way, if no other bends are required, the conductors can be fabricated from a rectangular sheet of a suitable metallic material with minimal wastage.

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 pole carrying an electrical cut-out; Figure 2 shows a perspective view of a cut-out according to the present invention; Figure 3 shows the cut-out of figure 2, from the front; Figure 4 shows the cut-out of figure 2, from the side; Figure 5 shows the cut-out of figure 2, in an exploded form; Figure 6 shows the internal conductor from above; Figure 7 shows the internal conductor from one end; Figure 8 shows the internal conductor from the side; Figure 9 shows a method of manufacture of known conductors; and Figure 10 shows a method of manufacture for the conductor of figures 6 to 8. * ** ** * * *.

DETAILED DESCRIPTION OF THE EMBODIMENTS * S

Referring to figure 1, a pole 10 is set into the ground surface 12 in order

SSSS

* to carry an electrical cut out 14 at the top of the pole. A three phase cable 16 is S..

carried in a conduit 18 beneath the ground surface and has incoming section 16a prior to the cut out and an outgoing section 16b subsequent to the cut out. The *** cable sections 16a and 16b are both bought up the pole 10 and enter the cut out units 14a, 14b and 14c from below, there being one cut-out for each conductor or phase. Of course, a pole 10 may be fortuitously present at a suitable location, in which case the cut out 14 may be mounted on it together with other equipment separate to the cable 16 or fed by the cable 16. The cut-out may be located other than on poles, such as in distribution enclosures, on walls, or elsewhere as required.

Other configurations could of course be adopted, such as two cut-outs for a two phase connection. There will usually be an earth connection in addition, but this would not normally be provided with a cut-out.

Figure 2 shows one cut out unit 14a in more detail. The remaining units 14b, 14c are (in this case) substantially identical. As a result of the cable morphology shown in figure 1 and in order to prevent ingress of water, the cable entry ports 20, 22 for the cut out 14 are aligned in a downward direction. Each has a grommet 24, 26 at the end of an elongate channel section 28, 30 which allows space for known forms of cable connector. For electrical distribution purposes, these connectors typically involve a clamp that can be bolted to a suitable conductor and which has a threaded member that can be used to compress the copper conductor against a bearing surface to achieve a good electrical contact. The threaded member may have a weak point or taper so that its head shears when a suitable torque is obtained, preventing a reverse torque from being applied and thereby locking the cable in place.

The two downward channels 30 depend from a central body region 32 and the three sections, together, define an inverted U-shape. In the central part of * * U, there is a removable link portion 34 with a handle 36. Grasping the handle 36 allows the link portion 34 to be withdrawn. As this carries a link conductor ***.

**** (not shown in figure 2) that bridges the electrical circuit from one incoming cable to the other, withdrawing the link portion 34 breaks the electrical connection and **** * operates the cut-out. a.. *

*:*::* Other external views of the cut-out 14 are shown in figures 3 and 4. In : like manner to the cable entry ports 20, 22, the link portion 34 is directed * generally downwardly so as to reduce the likelihood of water ingress.

Figure 5 shows the cut-out 14 in an exploded form. The main body part 32 of the cut-out comprises an upper shell 38 and a lower shell 40 which have been separated for the purposes of figure 5, and the link unit 34 withdrawn.

Within the cut-out 14, there are two internal conductors 42, 44, conductor 42 being shown in position and conductor 44 being shown slightly spaced from its seating on the lower shelf 40. Each conductor consists of an L-shaped strip of conductive metal such as copper and is formed with a range of holes to allow it to be bolted in place onto the lower section 40 and to allow a cable clamp to be attached. On the other flat section after the bend 46, a U-shaped recess 48 is provided to allow good electrical contact with the link conductor 50 carried by the link unit 34.

The link unit 34 has a single conductor terminated at either end with a pair of adjustable clamps, which can be tightened around the respective internal conductor 42, 44 by way of screws 52 disposed on the handle 36.

Figures 6, 7 and 8 show the internal conductor 42 in more detail. The other internal conductor 44 is identical albeit a mirror image. The conductor 42 comprises a generally L-shaped section of copper having a first generally flat portion 54 and a second generally flat portion 56 linked by a bend 58 between them. On one flat section 54, there is a mounting hole 60 to allow the conductor 42 to be bolted to the interior of the cut out unit 14, and a cluster of holes 62 to allow a cable clamp to be attached. On the other flat portion 56 there is a U-shaped recess 64 to allow a standard clamped connector to be attached.

* Figures 9 and 10 show the alternative production methods. Figure 9 ** shows the known production method for L-shaped conductors, which comprises S.. U **.. taking a sheet of material 66 and cutting out L-shaped pieces 68 therefrom.

This inevitably involves some waste 70. It may be possible to reduce this waste S...

* by suitable tessellation of the shapes 68, but this complicates the manufacturing S..

process and, generally, cannot product a perfect result given the dimensions * *.

* * . involved * ** S. * Figure 10 shows the production method for conductors according to the present invention, which consists of taking a strip 72 of suitable material and cutting this into suitable lengths 74. These can simply be bent at the appropriate place 76 with negligible wastage of material.

Accordingly, the present invention allows for a design of electrical cut out in which the wastage of expensive conductor material is minimised and yet the necessary geometry is maintained.

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. * S. * S * * S* S... * S S... S... S...

S S..

S * S. * S S * *5 S. S * S S S 55

Claims

1. An electrical cut-out, comprising a housing in which is mounted a pair of internal conductors, each terminated at one end with a cable connection and terminated at the other end adjacent an aperture in the housing, and a link unit having an insulating handle and a link conductor, the link unit being attachable to the housing such that at least the ends of the link conductor project through the aperture and make contact with the internal conductors, thereby to bridge them, wherein at least one of the internal conductors comprises an elongate conductive strip having a width greater than its thickness and having at least one bend therein in the plane defined by the thickness directions of the strip adjacent the bend.

2. An electrical cut-out according to claim 1 in which the bend is about 900.

3. An electrical cut-out according to claim 1 or claim 2 in which the at least one internal conductors comprises a flat plate previously subjected to a bending process.

4. An electrical cut-out according to any one of the preceding claims in which both of the internal conductors comprise an elongate conductive strip having a width greater than its thickness and having at least one bend therein in the plane defined by the thickness directions of the strip *(. adjacent the bend.

5. An electrical cut-out substantially as herein described with reference to and/or as illustrated in the accompanying figures 2 to 8 and 10.

S S..

S S *S * . . * S.

S * SS S.