GB2243497A

GB2243497A - Connection and earthing apparatus for electrical installations

Info

Publication number: GB2243497A
Application number: GB9105147A
Authority: GB
Inventors: Timothy Christopher Gilbert; Daniel Brendan Reidy
Original assignee: Electricity Supply Board
Current assignee: Electricity Supply Board
Priority date: 1990-03-12
Filing date: 1991-03-12
Publication date: 1991-10-30
Anticipated expiration: 2011-03-12
Also published as: IE900870A1; GB9105147D0; ZA911797B; IE62920B1; GB2243497B

Abstract

A connector includes a frusto-conical portion (220) for making an interference fit with a complementarily shaped socket. A screw threaded spigot (225) is rotatably mounted within the portion and engages with a screw threaded portion of the socket to provide a secure connection, rotation being effected by a hand tool engaging a bayonet connection (224). A kit includes leads (21) each having a connector, the hand tool and a selection of socketed adaptors differently designed to fit standard electrical fitments on conductors of an electrical installation to permit connections to be made to the installation or to provide earthing facilities. A parking bar can be mounted adjacent the installation, and includes plural sockets for parking the connectors. The kit is stored in a case and is particularly useful for attaching an adaptor to each phase of a supply using one end of the hand tool and then to earth using the connector/lead combination attached using the other end of the hand tool. <IMAGE>

Description

CONNECTION AND EARTHING APPARATUS FOR ELECTRICAL INSTALLATIONS The present invention relates to apparatus and method for connecting to electrical conductors, low voltage fuse panels, distribution boxes, underground boxes, lugged cables and the like, hereinafter for convenience collectively referred to as electrical installations, to facilitate take-off of electrical supplies and to provide a means of earthing an installation prior to repairs or servicing.

It is desirable that electrical installations, such as low voltage installations, not only be switched out, but earthed as well before work is carried out on them.

Often, however, due to the variety of different electrical terminations present within such installations it is time consuming and difficult to connect to the installations.

Accordingly, the necessary repair and servicing is often carried out without earthing, that is, carried out as if the electrical installation were "live". This may constrain the manner in which the operative carries out the repair and servicing.

An object of the present invention is to provide apparatus to enable a variety of different types of electrical installation to be connected to and earthed with ease and safety.

The invention provides-an electrical connection apparatus comprising an electrical cable having an interference fit connector at at least one end thereof whereby the cable may be connected between two electrical conductors by pushing the connector into a complementary shaped receiver provided on one conductor until a tight fit and an electrical connection are obtained.

Preferably, the connector further comprises a screw threaded spigot rotatable relative to a fixed portion of the connector, the rotation of which forces the spigot to engage with a complementary screw threaded bore in the receiver and bring the connector into more secure engagement with the receiver.

Advantageously, the screw threaded spigot is mounted on one end of a spindle housed within the fixed portion of the connector, the other end of the spindle having a bayonet fitting to enable the spindle and spigot to be rotated relative to the fixed portion.

Conveniently, the fixed portion of the connector has a frusto-conical shaped body for forming an interference fit with the receiver.

Preferably, the receiver is provided on an adaptor having means for securely connecting the adaptor to a conductor within an electrical installation.

Advantageously, the apparatus includes an insulated hand tool adapted to co-operate with the connector for forcing the connector to engage with the receiver.

Conveniently, the hand tool is provided with a spring loaded fitting for engaging the bayonet connector of the connector spindle.

Preferably, the hand tool further includes a screw threaded mounting for engagement with the screw-threaded bore of the receiver.

The present invention also provides a kit for making connections to or earthing an electrical conductor comprising apparatus as claimed in any preceding claim and including: (a) a set of leads for taking off supply to another electrical conductor or connecting the or each phase of an electrical supply in an installation to the neutral or to earth, each lead having a said interference fit connector, and (b) a plurality of adaptors to enable the connections to be made to a variety of different conductors.

Advantageously, the kit further comprises a parking bar for receiving the connectors in storage and in use, the bar having mounting means for mounting the bar on a support surface and receiving sockets for receiving each plug connector of the lead set.

Conveniently, the parking bar includes means for fixing the parking bar in position adjacent an installation.

Preferably, the set of leads are connected together as a star point connection harness.

Advantageously, the kit includes an adaptor for connecting a pair of fixed fork terminals for a fuse carrier, or an adaptor for connecting to both fork terminals of a fuse carrier, or an adaptor for connecting to stranded conductor or a round or flat busbar, or an adaptor for connecting to a tunnel or saddle terminal, or an adaptor for connecting to a low voltage connector block in an underground residential distribution system to provide a fixed connectable point in a busbar or cable system, or a bolt adaptor for connecting to a busbar or a cable.

Conveniently, the kit includes an earthing set for earthing a cable lug.

The present invention further provides a method of making connections to or earthing a conductor, comprising: (a) securing an appropriate adaptor having a connectable point to the conductor of an installation to be connected, and (b) connecting the or each phase of the supply in the installation to another electrical conductor or to the neutral or to earth by means of a set of leads engaging the or each connectable point, each lead having a said interference fit connector.

An operative who is repairing or servicing a number of installations brings the kit with him and uses the appropriate type of adaptor to create the connectable point on each type of termination as required. Thus, use of the kit permits a standard connectable point to be easily established at any point where it is required. The connectable point may be an earthable point.

The leads are connected together at a common point in the form of a harness with a standard plug connector at each termination. In use for earthing, the free end of one lead of the harness is connected to the neutral or earth and the free ends of the remaining leads of the harness are connected to the different phase terminals of the supply, and thus the different phases are earthed.

A variety of adaptors is provided to offer flexibility in the connection of the leads to the points of the installation to be connected or earthed. For example, points out of the plane that the operator may most easily work in as well as points which are small and relatively inaccessible may be readily connected or earthed by choice of a suitable adaptor.

Each free end of each lead is supplied with a standard plug connector which has a taper connector end for complementary engagement with a receiving socket on each adaptor. The taper connector ensures that a good connection between the lead and the adaptor may be obtained easily by a push fit. Furthermore the complementary screw-threaded nature of the leads and sockets ensures that good surface to surface connections are achieved. Each taper connector is also adapted to receive an insulated hand tool provided as a component of the kit, so that the operator may use the insulated hand tool to pick up the taper connector and connect the connector to the socket on the adaptor. The insulated hand tool may also be used to fit the adaptors to the installation terminals.

The kit includes one or more parking bars each with threaded sockets for retaining the free ends of the individual lead terminations when the leads are not in use, or for temporarily retaining the free ends during the operation of connection to or disconnection from the installation. The parking bars are so designed that they may be clamped to the lid of the carrying box, or to the cabinet or frame of the installation to be earthed, by means of two wing nuts.

The invention will now be described more particularly with reference to the accompanying drawings which show, by way of example only, one embodiment of a kit according to the invention suitable for earthing. The kit can of course be adapted for other applications in connecting to electrical installations.

In the drawings: Figure 1 is a plan view of the box containing the kit, shown open so that the parts of the kit are visible; Figures 2a and 2b are side and end views respectively of the box shown closed; Figure 3 shows the parking bar for holding the earthing lead harness when not in use; Figure 4 shows the parking bar secured to a pole by means of a webbing strap; Figure 5 shows an insulated hand tool for.use in securing or releasing the adaptors and securing or releasing the earthing leads; Figure 6 shows the earthing leads in the form of a harness for connecting the or each phase of a three phase supply to neutral or earth; and Figures 7 to 12 each show a different type of adaptor, namely panel, clamp, tunnel, link, stud and bolt head adaptors respectively.

Figures 13a to 13c show a cable lug connector set and a clamp of the set.

Referring initially to Figure 1, the kit is contained in a box 1, and comprises sets of earthing harnesses 2, panel adaptors 3, clamp adaptors 4, tunnel adaptors 5, neutral link adaptor 6, stud adaptor 7, bolt adaptor 8, cable lug earthing set represented diagrammatically by 9, parking bars 10, and an insulated hand tool 11.

The components are arranged in the box 1 so that when the box 1 is opened all the components are readily accessible for use. For this purpose the parking bars 10 are secured to the inside of the lid flaps 14. As the lid 14 is opened, the parking bars 10 and the harnesses 2 which are connected thereto emerge from the box 1, allowing access to all the other components on the floor of the box 1.

Furthermore, stops 12 (see Figures 2a and 2b) are provided on the outside walls of the box 1 so that when the lid flaps 14 are opened they rest in an inclined or sloped orientation for ease of use of the harness 2. The other components are mounted in a holder 13 which comprises a flat panel provided with cut-outs for receiving each component.

In use, the electrical installation is first switched off.

The installation is then checked for the absence of voltage. If there is no voltage present adaptors 3, 4, 5, 6, 7, 8 or cable lug earthing set 9 as appropriate are then attached to the neutral or earth and to one or more of the three phases of the installation. The choice of adaptor 3, 4, 5, 6, 7, 8 or cable lug earthing set 9 depends on the particular termination to be earthed. The insulated hand tool 11 or other insulated means is used to move the adaptors 3, 4, 5, 6, 7 or 8 from the box to the phase termination. The adaptors 3, 4, 5, 6, 7, 8 or cable lug connector set 9 are then secured in position by tightening the torquing key, screws or other fastening mechanism, making use of an insulated hand tool, screw driver or other tool, or by hand wearing rubber gloves. A clamp of the cable lug connector 9 is secured on the lug by an insulating torquing key.Then, again using the insulated hand tool 11, the free ends of the electrical harness 2 are detached one by one from the parking bar 10 and engaged in the adaptors 3, 4, 5, 6, 7 or 8 thus connecting each of the three phase terminations to the neutral or earth and thereby earthing the installation.

In the case of cable lug earthing, earthing is completed directly by the application of each of the lug clamps of the cable lug earthing set 9 and connecting the free end to the adaptors 3, 4, 5, 6, 7 or 8 or the earth or neutral.

Referring now to Figures 3 and 4, as a preliminary to earthing the installation, a parking bar 10 may be detached from the box 1 and then attached to a convenient point on or near the installation. This relocation facilitates the subsequent step of dismounting the terminations of the electrical leads from the parking bar 10 and inserting them in the adaptors 3, 4, 5, 6, 7 or 8.

The parking bar 10 may be released from the box by means of wing nuts 101 and attached to the installation. In certain situations it may not be possible to mount the parking bar 10 in the new position by clamping. In one such situation, shown in Figure 4, the parking bar 10 may be held in position by means of a webbing strap 15 which constitutes a component of the kit.

Referring now to Figure 5, the insulated hand tool 11 and its use will now be described in more detail. The main body comprises an insulated handle 111. One end is tapered and finishes in an externally screw threaded stud 112, the other end is a socket with a spring loaded receiver 113 for a bayonet fitting. When used to move an adaptor 3, 4, 5, 6, 7 or 8 into position, the tapered screw threaded end 112 of the insulated hand tool 11 is inserted into a complementary screw threaded connector socket provided in the adaptor 3, 4, 5, 6, 7 or 8. Each of the adaptors 3, 4, 5, 6, 7 and 8 is provided with such a socket.

When used to move the harness connector from the parking bar 10 to the adaptor 3, 4, 5, 6, 7 or 8, the bayonet end of the connector of the harness 2 is inserted into the socket end 113 of the insulated hand tool 11 which is then used to insert the tapered end of the connector of the harness 2 into the socket on the adaptor 3, 4, 5, 6, 7 or 8.

Referring now to Figure 6, the common point connection harness 2 comprises three leads 21 for the three phases, and a lead 21 for the earth. All leads are of equal length (not shown) to provide a star point connection on any earthed installation. Each free end of each lead comprises a standard plug connection termination 22 having a fixed taper section 220 connected to a rotatable portion 223 having lugs 224. A bayonet end 222 is jointed on the rotatable portion 223. A spindle 226 is formed on the portion 223 and extends through the taper connector 220 to the threaded spigot end 225. The taper section 220 is first push fitted into a complementary conical shaped portion of an adaptor socket, then is secured in the socket by screwing the threaded spigot 225 into the adaptor socket using the socket end 113 of the insulated hand tool 11 to twist the bayonet end 222 of the plug connector.

In the following paragraphs the panel, clamp, tunnel, link, stud and bolt adaptors 3, 4, 5, 6, 7, 8 and cable lug connector set 9 respectively, and their uses, will be described in more detail with reference to Figures 7 to 13 of the drawings.

The panel adaptor 3 shown in Figures 7a, 7b and 7c is used to earth one of the fixed fork-type contacts of a fuse carrier, while the plastic housing shrouds the other contact which is not earthed. The panel adaptor 3 can be used at fuse terminations in sub-station panels, and underground boxes. Figures 7a, 7b and 7c are front elevation, top plan and bottom plan views respectively.

The adaptor 3 comprises a fixed jaw 31, and a movable jaw 32 which together define a wedge clamp. The movable jaw 32 is operated by means of a torquing key at 33. The jaws 31 and 32 are contained within a housing 34 made of plastics material. A receiving socket 35 is provided for receiving the connector plug shown on the harness 2 and for receiving the threaded stud 112 of insulated hand tool 11.

The clamp adaptor 4 shown in Figure 8 is used for providing earthing facilities to a stranded conductor, or round or flat busbars. The clamp adaptor 4 comprises a fixed jaw 41, and a movable jaw 42 which together define a flat clamp. The movable jaw 42 is operated by means of a torquing key at 43. The clamp includes two mutually perpendicular sockets 44 either of which may be used as is convenient.

The tunnel adaptor 5 shown in Figures 9a and 9b is used for providing an earthing point at various tunnel and saddle terminals, for example minipillar busbars. Figures 9a and 9b are side and front elevation views respectively.

The adaptor 5 comprises a stem 51 having a round profile 511 along part of its length and a rectangular profile 512 along the remainder of its lengths and a head 52. The head 52 includes a receiving socket 53. The head also includes a saddle clamp 54 to allow connection, via the adaptor 5, of a service cable which may have to be disconnected to make way for the adaptor.

The link adaptor 6 shown in Figures 10a and 1Ob is used to provide a connectable point when both forked terminals in a fuse outlet have to be connected together, for example, boxes with solid link neutrals. Figures 10a and 1Ob show plan views and front elevation views respectively. The adaptor comprises two relatively movable plates 61 which define a clamp. The plates are operated by means of screws 62. A receiving socket block 63 is provided.

The stud adaptor 7 shown in Figure 11a and lib is used to earth the low voltage connector block in an underground residential distribution (U.R.D) or a bolted fixed earthing point on a busbar or cable system. Figures lia and lib show front elevation and plan views respectively.

The adaptor 7 comprises a bolt with a hexagonal head 71 with a standard socket to accept a connector plug shown on the earthing harness 2.

The bolt adaptor 8 shown in Figures 12a and 12b is used to provide earthing points on busbars or cable lugs by using it as a bolt. Figures 12a and 12b are front and side elevation views respectively. A socket 81 comprising a connectable point is provided in the head 82 of the bolt at right angles to the shank 83.

The adaptors 7 and 8 also allow permanent connectable points to be provided in inaccessible locations, for example, within U.R.D. or minipillar installations.

The cable lug earthing set 90 consists of up to four cable lug clamps 9 connected together in series by insulated flexible conductors 96 and extended to a connector plug 220, as shown in perspective in Figure 13a. The lug clamp of 9 is shown in Figures 13b and 13c and is used to earth feeder cables. Figures 13b and 13c are side elevation and plan views respectively. The clamp 9 is encapsulated in insulating plastic. The lug 97 of the cable to be earthed is inserted into a slot 91 in the body of the clamp and is clamped by means of a torquing key 98 at 92. The insulated flexible conductor 96 is inserted through the hole 93 in each clamp and extended to a plug connector 22.

The conductor is clamped in position by saddle 94 and tightened by screws 95. Removable plastic insulating bungs 99 are fitted through the holes in the encapsulation to insulation screw 95.

An advantage of the kit and method according to the invention is that since connectable points are created within the installation itself, once the earthing has been achieved, for example in a minipillar, the protective cover can be replaced over the minipillar and the operator can go and work elsewhere, knowing that the minipillar is tamper proof and does not constitute a hazard to the public.

Claims

CLAIMS:

1. An electrical connection apparatus comprising an electrical cable having an interference fit connector at at least one end thereof whereby the cable may be connected between two electrical conductors by pushing the connector into a complementary shaped receiver provided on one conductor until a tight fit and an electrical connection are obtained.

2. An apparatus as claimed in Claim 1 wherein the connector further comprises a screw threaded spigot rotatable relative to a fixed portion of the connector, the rotation of which forces the spigot to engage with a complementary screw threaded bore in the receiver and bring the connector into more secure engagement with the receiver.

3. An apparatus as claimed in Claim 2 wherein the screw threaded spigot is mounted on one end of a spindle housed within the fixed portion of the connector, the other end of the spindle having a bayonet fitting to enable the spindle and spigot to be rotated relative to the fixed portion.

4. An apparatus as claimed in Claim 2 or Claim 3, wherein the fixed portion of the connector has a frusto-conical shaped body for forming an interference fit with the receiver.

5. An apparatus as claimed in Claim 4 wherein the receiver is provided on an adaptor having means for securely connecting the adaptor to a conductor within an electrical installation.

6. An apparatus as claimed in any of the preceding claims including an insulated hand tool adapted to co-operate with the connector for forcing the connector to engage with the receiver.

7. An apparatus as claimed in Claim 6 wherein the hand tool is provided with a spring loaded fitting for engaging the bayonet connector of the connector spindle.

8. An apparatus as claimed in Claim 6 wherein the hand tool further includes a screw threaded mounting for engagement with the screw-threaded bore of the receiver.

9. An kit for making connections to or earthing an electrical conductor comprising apparatus as claimed in any preceding claim and including: (a) a set of leads for taking off supply to another electrical conductor or connecting the or each phase of an electrical supply in an installation to the neutral or to earth, each lead having a said interference fit connector, and (b) a plurality of adaptors to enable the connections to be made to a variety of different conductors.

10. A kit as claimed in Claim 9 further comprising a parking bar for receiving the connectors in storage and in use, the bar having mounting means for mounting the bar on a support surface and receiving sockets for receiving each plug connector of the lead set.

11. A kit as claimed in Claim 10 in which the parking bar includes means for fixing the parking bar in position adjacent an installation.

12. A kit as claimed in any of Claims 9 to 11 in which the set of leads are connected together as a star point connection harness.

13. A kit as claimed in Claim 9 including an adaptor for connecting a pair of fixed fork terminals for a fuse carrier.

14. A kit as claimed in Claim 9 including an adaptor for connecting to both fork terminals of a fuse carrier.

15. A kit as claimed in Claim 9 including an adaptor for connecting to stranded conductor or a round or flat busbar.

16. A kit as claimed in Claim 9 including an adaptor for connecting to a tunnel or saddle terminal.

17. A kit as claimed in Claim 9 including an adaptor for connecting to a low voltage connector block in an underground residential distribution system to provide a fixed connectable point in a busbar or cable system

18. A kit as claimed in Claim 9 including a bolt adaptor for connecting to a busbar or a cable.

19. A kit as claimed in Claim 9 including an earthing set for earthing a cable lug.

20. A method of making connections to or earthing a conductor, comprising: (a) securing an appropriate adaptor having a connectable point to the conductor of an installation to be connected, and (b) connecting the or each phase of the supply in the installation to another electrical conductor or to the neutral or to earth by means of a set of leads engaging the or each connectable point, each lead having a said interference fit connector.

21. An electrical connection apparatus or an electrical installation earthing kit substantially as herein described with reference to and as shown in the accompanying drawings.

22. A method of making connections to or earthing an electrical conductor substantially as herein described with reference to the accompanying drawings.