GB2187851A

GB2187851A - Anti-tamper electric meters

Info

Publication number: GB2187851A
Application number: GB08705707A
Authority: GB
Inventors: John Thomas Clark; Michael Charles Stephe Simpson
Original assignee: Associated Electrical Industries Ltd
Current assignee: Associated Electrical Industries Ltd
Priority date: 1986-03-12
Filing date: 1987-03-11
Publication date: 1987-09-16
Also published as: GB8705707D0

Abstract

A combination of an electric kWh meter (1) and a house service cutout (2), in which the latter has terminals (3, 6, 10) which align with those (4, 8, 5) of the meter and is disposed immediately beneath and substantially in contact with the meter, with conductors (11, 12, 13) extending directly between the cutout and meter terminals. By this means exposed interwiring is avoided and the possibility of fraudulent interference substantially prevented. <IMAGE>

Description

SPECIFICATION Arrangements incorporating electric meters This invention relates to arrangements incorporating electric meters of the kind, commonly called KWh meters, for use in recording the amount of electric power supplied to a consumer by an Electrical Supply Authority, and associated house service cutouts.

In conventional supply installations the incoming cable up to and including its termination in the cutout is secure, and the wiring from the meter to the consumer, being metered, offers no opportunity for fraudulent interference. However the unmetered wiring that exists between a cutout and meter is vulnerable to interference and illegal extraction of energy.

An object of the invention is to provide a meter/cutout arrangement which substantially prevents such interference.

According to the invention in an arrangement incorporating an electric meter of the kind referred to and an associated house service cutout, the latter has terminals which align with those of the meter, and the cutout is disposed immediately beneath and substantially in contact with the meter, with conductors extending directly between the cutout terminals and respective meter terminals.

The close coupling between the cutout and meter in such an arrangement, avoids the need for exposed interwiring and substantially eliminates the possibility of fraudulent interference.

It is only necessary for the parts of the meter and cutout casings around the line and neutral conductors on the supply side of the meter to be disposed sufficiently close to prevent intereference, and the meter and/or cutout casing(s) may be shaped so that the consumer's line and/or neutral conductor(s) extend from terminals in the meter in the usual way, though through a reduced gap between them, or alternatively through slots or other openings in the casing of the meter or cutout.

However in some cases the line and neutral conductors from the meter may pass back to the cutout to be connected to the consumer wiring terminals accommodated within the cutout.

The conductors between the cutout and the meter are conveniently provided by solid conducting pins extending from the appropriate terminals of the cutout or meter and into conventional terminals of the meter or cutout, as the case may be, where they can be clamped by means of the normal pinching screws.

Conveniently there are at least two such pins, one of which forms a connection between the cutout outgoing line terminal and the meter ingoing line terminal and the other forms a connection between the meter outgoing line terminal and a respective cutout terminal, the latter being connected to the consumer line conductor.

However connection between the cutout and meter may alternatively be by means of a suitable plug and socket arrangement.

Preferably the cutout and meter terminal covers are such as to be removable only after breaking the fuse carrier seal, being preferably interlocked with the fuse carrier cover. The cutout and meter terminal covers may be interlocked one with another or formed integrally with each other.

Now there is, at the present time, a large and growing requirement for two rate tariff meters which allow a consumer to be changed at the lower rate for electricity supplied during off-peak demand periods. The periods are controlled by switching equipment which operates on two registers contained within the meter housing.

Accordingly in an arrangement in accordance with the present invention in which the meter has two registers, the arrangement incorporates, in addition, switching equipment of the above kind mounted in a housing adjacent to the meter/cutout assembly, and a connector box substantially contacting the cutout and switching equipment housings, with conductors extending directly between the cutout and switching equipment tQ provide connections between the switching equipment and the meter registers, and the connector box also containing the consumer terminals.

By arranging for the connector box to have close coupling with both the cutout and the switching equipment housing, the interconnections have the same security as that provided between the cutout and meters of the first arrangement above described.

In a similar manner the conductors between the different units of the arrangement, in this case between the cutout and meter, between the cutout and connector box, and between the connector box and switching equipment may be provided by solid conducting pins extending between terminals of the respective units, such pins conveniently being clamped into the terminals in known manner by conventional pinching screws, or alternatively the connections between at least one pair of units being effected by means of a suitable plug and socket arrangement.

The cutout itself will be similar to that employed in the first arrangement except that it will incorporate, in addition, a segregated channel in the cutout moulding to accommodate the register switch conductor when required.

The connector box preferably has a removable cover interlocked with that of the sealed fuse carrier cover which extends over the cutout compartment so that it cannot be removed until the sealed fuse carrier is extracted.

Two embodiments of the invention will now be described by way of example with reference to Figs. 1 to 7 of the accompanying schematic drawings, in which Figure 1 illustrates diagrammatically the conventional arrangement of a KWh meter and service cutout, Figure 2 is a similar diagrammatic illustration of a meter/cutout arrangement forming the first embodiment of the invention, Figures 3 and 4 represent a front view and side view of that arrangement shown in more detail, Figure 5 is a diagrammatic illustration of the various connections between the different units of a meter/cutout/switch arrangement forming the second embodiment of the invention, Figure 6 illustrates a front view of part of this second arrangement, and Figure 7 represents a diagrammatic representation of a modified form of this second arrangement.

Referring first to Fig. 1 this shows a typical meter and cutout arrangement as commonly installed at the present time, for use with a Protective Multiple earthed network employing a combined neutral and earthed incoming cable NE in known manner, the meter 1 being spaced a matter of inches above the cutout 2, with connections between them formed by short lengths of insulated cable. Thus a conductor L1 connects the line fused outgoing terminal 3 of the cutout 2 to a corresponding terminal 4 of the meter 1, the consumer's line conductor LC being connected to a respective outgoing terminal 5 of the meter, Similarly a further connection N1 is made between the neutral outgoing terminal 6 of the cutout and a terminal 7 of the meter with the consumer's neutral conductor NC connected to a further outgoing terminal 8 of the meter.The consumer's earth conductor is taken directly from a respective terminal 9 of cutout 2.

It will, however, be appreciated that the zone between the cutout and meter could be subject to interference. This is prevented by an arrangement in accordance with the present invention as illustrated in Figs. 2 to 4.

Thus, in accordance with the invention, associated terminals of the cutout 2 and meter 1 are disposed in alignment, and the meter is disposed directly in contact with the top of the cutout, with the respective meter and cutout terminals interconnected with solid conductors. These as shown in Fig. 3, can be in the form of conducting pins 11, 12, 13 projecting from the top of the cutout 2 into the appropriate terminal bores of the meter 1.

It will be seen that the line fused outgoing terminal 3 of the cutout 2 accommodates the solid pin 11 which is suitably positioned to align with the meter line terminal 4, the neutral outgoing terminal 6 of the cutout accommodates the second solid pin 12 suitably positioned to align with the meter outgoing neutral terminal 8, and a further terminal 10 accommodates the third pin 13 which is positioned to align with the meter outgoing line terminal 5.

The cutout terminal 10 also connects with a cable bore 14 at the side of the cutout for enabling it to be connected to the consumer's line conductor LC. The cutout neutral terminal block 15 contains a further three cable bores to accommodate the consumer's neutral and earth connectors NE and EC and an equipotential bonding lead B, whch pass out through respective openings 16 in the wall 17 of the cutout.

The cutout neutral terminal cover 18 is arranged to be interlocked with the fuse carrier 19 to the cutout 2 so as to be prevented from unauthorised removal by the sealing of the fuse carrier to the cutout housing in accor- dance with the normal Supply Authority Practice. The cutout cover 18 is also interlocked with the meter terminal cover 21 as shown in Fig. 4 It will be seen that such an arrangement effectively eliminates any possibility of interference with the conductors between the cutout 2 and the meter 1.

The meter itself may be of conventional design, the three current carrying pins 11, 12 and 13 which project from the top of the cutout 2 and pass into the respective terminal bores of the meter 1 being clamped to the terminals by means of the usual terminal screws, as at 22. However, in some cases the meter terminals could be modified so that connection between the meter and cutout is achieved by means of a plug and socket arrangement.

In a modification of the arrangement described neutral cover could be formed integrally with the meter terminal cover.

In a further modification the solid terminal pin 12 could be replaced by a small current carrying wire, as it is now only a connection for the meter voltage coil.

In yet another modification the meter and cutout may be combined to form a single integral unit, conveniently with a common outer casing.

The second embodiment of the invention comprises a meter 1, and cutout 2 disposed as illustrated in Fig. 2 with co-operating terminals of the meter and cutout being similarly disposed in alignment and interconnected with solid conductors, and the meter being dis posed directly in contact with the top of the cutout.

However the meter 1, in this case, is a two rate tariff meter having a main coil 23 carrying the constant load current and forming part of the main register and an auxiliary coil 24 which is energised during off-peak periods and forms part of an off-peak register.

The meter 1 has associated with it a time switch 25 incorporating a timer clock 26 ar ranged to operate main and auxiliary contacts 27, 28 as will subsequently be described.

A moulded connector box 29 is located with its top surface immediately beneath the time switch 25 and a side surface in contact with the side of the cutout 2. Outgoing conductors from the cutout 2, in this case, pass directly into terminals in the connector box, and connections are made directly between the connector box and the time switch. Consumers line and neutral conductors are connected to terminals in the connector box, the constant load line terminal 31 together with the neutral terminal 32 being located adjacent the bottom of the box, and the off-peak load line terminal 34 being located at the side of the box remote from the cutout. Terminal 33 allows earthing of the time switch case.

The connector box cover interlocks with the cutout 2, the cover extending over the front of the cutout so that it cannot be removed until the fused carrier of the cutout is extracted. Thus the connector box 29 ensures close coupling with both the cutout 2 and time switch 25 so that all connections have the same security as that provided between the meter and the cutout and in some cases can provide a simple plug in feature.

Fig. 7 shows an arrangement similar to that of Figs. 5 and 6 except the line connection to the time switch 25 is taken from the incoming side of the meter 1. The power consumption of the time switch is therefore not registered by the meter.

Claims

1. An arrangement incorporating an electric meter of the kind referred to and an associated house service cutout, wherein the cutout has terminals which align with those of the meter, and is disposed immediately beneath and substantially in contact with the meter, with conductors extending directly between the cutout terminals and respective meter terminals.

2. An arrangement according to Claim 1 wherein the conductors between the cutout and meter are provided by solid conducting pins extending from appropriate terminals of the cutout or meter and into conventional terminals of the meter or cutout, as the case may be.

3. An arrangement according to Claim 2 incorporating at least two such pins, one of which forms a connection between the cutout outgoing line terminal and the meter ingoing line terminal and the other forms a connection between the meter outgoing line terminal and a respective cutout terminal, the latter being connected to the consumer line conductor.

4. An arrangement according to Claim 1 wherein the connections between the cutout and meter are provided by a plug and socket form of coupling.

5. An arrangement according to any preceding Claim wherein the cutout and meter terminal covers are such as to be removable only after breaking the fuse carrier seal.

6. An arrangement according to Claim 5 wherein the cutout and meter terminal covers are interlocked with the fuse carrier cover so that they cannot be removed before removal of the latter.

7. An arrangement according to any preceding Claim in which the meter has two registers, the arrangement incorporating switching equipment which operates on the two registers and is mounted in a housing adjacent the meter/cutout assembly, and a connector box substantially contacting the cutout and switching equipment housings, with conductors extending directly between the cutout and switching equipment to provide connections between the switching equipment and the meter registers, and the connector box also containing the consumer terminals.

8. An arrangement according to Claim 7 wherein the conductors between the different units of the arrangement, that is between the cutout and meter, between the cutout and connector box and between the connector box and switching equipment, are provided by solid conducting pins extending between the terminals of the respective units.

9. An arrangement according to Claim 7 or 8 wherein the connector box has a removable cover interlocked with that of the sealed fuse carrier cover which extends over the cutout compartment so that it cannot be removed until the seal fuse carrier is extracted.

10. An arrangement incorporating a meter of the kind referred to and an associated house service cutout substantially as shown in and as hereinbefore described with reference to Figs. 2 to 4 of the accompanying drawings.

11. An arrangement incorporating an electric meter of the kind referred to having two registers, an associated house service cutout and switching equipment operating on the two registers of the meter, substantially as shown in and as hereinbefore described with reference to Figs. 5 to 7 of the accompanying drawings.