GB2530798A

GB2530798A - Electrical connections

Info

Publication number: GB2530798A
Application number: GB1417485.8A
Authority: GB
Inventors: Daniel David Watson
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-10-03
Filing date: 2014-10-03
Publication date: 2016-04-06
Also published as: GB201417485D0

Abstract

An electrical power wiring system comprising; Wall box (27, figure 11), power socket (25), power supply, and an electrical power connection 20 having; a pin 21 which fits into one of the terminals of the socket, insulator 23 surrounding a plurality of ports 24, which are in electrical continuity, and into which conductors of the wiring system are fittable. The dimensions of the electrical connections, when fitted to the socket, are compatible with the internal size of the wall box. Preferably the wall socket is for either power or lighting circuits, and the ports are designed similar to figure 7 with all the ports connected together by member 16. Preferably the ports are in a 1 x 3 matrix and the pin is either located near the end or the middle of the ports. Preferably the three ports of the connector are intended for ring main in (R1), ring main out (R2) and an optional power spur (S1). The connection preferably allows for a simpler, tidier wiring to the socket, reducing fires caused by electrical faults.

Description

ELECTRICAL CONNECTIONS

This specification relates to electrical connections, and specifically to improving the speed s of making connections and the reliability of the connections thus made. It is also particularly concerned with reducing the risks of fires resulting from electrical faults.

The principles of wiring domestic and other properties with electrical ring mains are well known and understood. However, a large number of fires, particularly in domestic dwellings are subsequently identified as having started due to electrical faults'. In many cases, the cause is overloading the circuit, e.g. by using power trails to which high power appliances are attached. By law, ring mains are protected by fuses or circuit breakers, yet fires still occur. Clearly, if the total amperage, or wattage, being drawn is greater than the fuse or circuit breaker rating it will blow or trip. However, the fact that so many fires due to electrical faults', frequently resulting in deaths, do occur is a cause for great concern.

Often the actual cause of the fire is down to problems arising from the electrical connections in ring main wall sockets.

Figs. 1-3 show a major problem with electrical connections. Figs. 1-3 are diagrammatic sections through a terminal 1 with a securing screw 2 and two conductors 3 and 4.

Conductors 3 and 4 are, for example, the two line leads of a ring main. In a ring main, there must be two conductors but there may also be a third if a spur is being run from the socket. For simplicity, the description and drawings will be restricted to just two conductors, 3 and 4. Fig. 1 shows screw 2 withdrawn so that conductors 3 and 4 can be inserted. In Fig. 2, screw 2 is being advanced and tip 2A has pushed conductor 3 to one side and is bearing more directly on conductor 4.

In Fig. 3, screw 2 is fully tightened and the contact pressure (Hertzian stress) from tip 2A has distorted conductors 3 and 4, as shown 3A and 4A. Fig. 4 shows an enlargement of the contact area between tip 2A and conductors 3A and 4A. As shown, the direct contact volumes of the conductors with tip 2A and between terminal 1 are shown hatched areas 36 and 4B respectively. (As the purpose of sectional Figs. 1-5 is to show the effects on volumes 3B and 4B, only these areas are hatched to avoid confusing detail.) Volumes 3B and 46 are highly stressed; and in tight direct contact with the inside of terminal 1, i.e. there is minimal electrical resistance, so that the majority of the current passing between conductors 3 and 4 and terminal 1 will pass through volumes 36 and 4B.

As volumes 3B and 4B are less that the full cross sectional area of conductors 3 and 4, the -.

higher current density will cause heating in volumes 38 and 46. When the current passing is high, considerable heating can occur, raising the temperature locally in volumes 36 and 4B. If an elevated temperature is maintained for long periods of time, creep in the metal can occur Creep acts to reduce the stress in the metal and causes the metal to flow'.

Overtime, this can reduce the size of volumes 3B and 46 and also the contact pressures with tip 2A and terminal 1, i.e. leading to an increase the electrical resistance; this will cause IR heating to increase. Thus, long-term heating in the socket could have a positive, but detrimental, feedback effect.

Fig. 5 is a section along the line PA in Fig. 3 about centre line 8. As shown in Figs 1-3, conductor 3 is pushed to one side by screw 2 so that screw threads 2B will bite into the metal of conductor 3A (Fig. 4). Tightening 9 screw 2 will cause threads 26 to exert a force 6 on conductor 3A. If force 6 is greater that the frictional force between conductor 3A and terminal 1 at point 7, there will be a net force acting to move conductor 3A in the direction of arrow 6. If conductor 3 was not pushed fully into terminal 1, the effect of tightening 9 could be to weaken the grip with terminal 1 or even remove it altogether. If the conductor 3A did lose contact, this would double the power density in the remaining part of the ring main. If the electrician filling the socket did not notice this, it could have serious consequences.

Thus, there is an urgent need to produce a means to improve the reliability of ring main, and like connections and, if this could be done by reducing the time and effort involved, that According to the invention, there is provided an electrical power wiring system comprising:-i) an electrical power wall mountable socket; ii) a wall box into which the electrical power socket is securable; iii) an electrical power supply accessible via the wall box; and iv) an electrical power connection having a pin adapted to fit into one of the line, neutral or earth terminals of the socket and also having a plurality of ports each of which ports is in electrical continuity with the other ports and with the pin and into each of which ports a conductor forming part of the electrical wiring system is

fittable;

characterised in that the pins of three of the electrical power connections are fitted into the line, neutral and earth terminals of the socket respectively and that the conductors of the wiring system are filled into appropriate ports on the three connections and that the socket, complete with the three electrical connections and wiring conductors fitted therein is secured into the wall box and further characterised in that the dimensions of the electrical power connections when fitted to the socket are fully compatible with the internal size of the wall box so that the socket may be properly secured into the wall box without jeopardising any of the wiring system conductors or their fillings to the ports of the electrical power connections.

According to a first variation of the apparatus of the invention, the electrical power socket is a 1 3A power socket.

According to a second variation of the apparatus of the invention, the electrical power socket is a 13A power socket having a power spur taken therefrom.

According to a third variation of the apparatus of the invention, the electrical power socket is a lighting switch.

According to a fourth variation of the apparatus of the invention, the electrical power socket is a multi-way lighting switch.

According to a fifth variation of the apparatus of the invention, the wall box is a standard size unit for power or lighting applications.

According to a sixth variation of the apparatus of the invention, a part of the pin is electrically insulated.

According to a seventh variation of the apparatus of the invention, the electrical power connections are provided with three ports.

According to an eighth variation of the apparatus of the invention, the pin is located near one end of the plurality of three ports.

According to a ninth variation of the apparatus of the invention, the pin is located centrally or towards the centre of the plurality of three ports.

According to a tenth variation of the apparatus of the invention, each of the ports is provided with a quick electrical connection means so that the bared conductor has only to be inserted into the port and pushed in for it to! be held permanently fast and in electrical continuity with the rest of the electrical power connection.

According to an eleventh variation of the apparatus of the invention, the electrical power connection is provided with electrical insulation in appropriate places.

According to a twelfth variation of the apparatus of the invention, the quick electrical connection, once made, is maintenance-free According to a thirteenth variation of the apparatus of the invention, the conductors of the wiring system include line ring main in & line ring main out and neutral ring main in & neutral ring main out and earth ring main in & earth ring main out for each of the line, neutral and earth terminals on the socket.

According to a fourteenth variation of the apparatus of the invention, the conductors of the wiring system include line ring main in & line ring main out and neutral ring main in & neutral ring main out and earth ring main in & earth ring main out for each of the line, neutral and earth terminals on the socket and a spur.

In a preferred application of the apparatus of the invention, an electrical connection is provided in the form of a matrix with a connection pin so that the pin and all the ports in the matrix are in electrical continuity with each other. Each port of the matrix is provided with a means to allow a bared conductor wire to be inserted and pushed home so that it is permanently held. Preferably, the connection matrix has three ports. To wire up a power socket, the pins of three of the connectors are inserted, one into each of the line, neutral and earth terminals of the socket and secured therein. The wires of the ring main are now prepared, inserted and pushed home into the ports of each connector. In the case of a standard ring main, the wiring would be ring main in, ring main out and a spur (if required).

The connections are designed as 3 x I matrices so that, when the pin is secured in the socket terminal, the extra depth added to the socket is compatible ith the clearance provided by standard size wall boxes so that the sockets may be wired up and fitted flush with the walls. Because the connection matrices have three ports each, there is capacity for the ring main wire in, the ring main wire out and a spur. If no spur is required, one port will be unused.

The matrix connections are designed for use with either power or lighting circuits but are applicable to other forms of electrical wiring.

For a clearer understanding of the invention and to show how it may be carried into effect, reference wilt now be made, by way of example only, to the accompanying drawings in which:-Figure 1 is a diagrammatic elevation of two conductors inserted into a terminal

connection (prior art);

Figure 2 is a diagrammatic elevation of the two conductors of Fig. I inserted into a terminal connection as the screw is beginning to tighten (prior art); Figure 3 is a diagrammatic elevation of the two conductors of Fig. 1 inserted into a terminal connection after the screw is fully tightened (prior art); Figure 4 is an enlarged view of the compressed connectors in Fig. 3 (prior art); Figure 5 is a part sectional plan view along the line AA of one of the compressed

connectors in Fig. 3 (prior art);

Figure 6 is a plan view of a 2 x 2 matrix WAGOe connector (prior art); Figure 7 is a sectional view along the line BB of the WAGO® connector of Fig. 6 (prior art); Figure 8 is a plan view of a connector according to the invention showing the position of the pin near one end of the plurality of connection ports; Figure 9 is a plan view of a connector according to the invention showing the position of the pin at the centre of the plurality of connection ports; Figure 10 is a plan view of the rear of a I 3A socket showing the fitting and wiring of three of the connectors of the invention; and Figure 11 is a sectional elevation of the socket of Fig. 10 fitted into a wall box with part of the ring main wiring.

In the following description, the same reference numeral is used for the same component in different Figures and / or for different components fulfilling identical functions.

Figs. 6 and 7 show a type of connector 10 produced by WAGO® Kontackttechnik GmbH & Co. Fig. 6 is a plan view showing the 2 x 2 matrix nature of the connector, with four holes 12 for conductors in insulation 11. The connections below holes 12 are all in electrical continuity with each other, i.e. a power input to one hole 12 would permit a power take off from any/all of the remaining holes 12. Fig. 7 is a sectional elevation along the line BB in Fig. 6. As shown in Fig. 7 an insulated 13 conductor 14 has been inserted and pushed into hole 12 on the right hand side, where conductor 14 slides down the side of member 16 and under spring loaded member 15. The end of member 15 bites into the metal of conductor 14, stopping its withdrawal so that, once made, the connection is permanent. This is a quick connection' as no screwing 2 is required. The connection is maintenance-free.

No conductor is fitted into hole 12 on the left hand side to show the connection principle before use. Fig. 7 also shows how member 16 provides electrical continuity to conductors in all four holes 12.

S Connectors of the WAGO® type are too big to be used in standard size wall boxes.

However, if the 2 x 2 matrix was re-arranged into a 1 x 3 matrix 20, as shown in Figs. 8 and 9, they would fit. Also, if a connecting pin 21 was provided, the matrix 20 could be fitted directly into a terminal 1 on the rear 26 of a wall socket 25 and the whole assembly be fined (Fig. 11) in the clear space 28 available in wall box 27. Matrices 20 would be similar in form to that shown on the right hand side of Fig. 7, i.e. to the right of centreline 17, i.e. with the quick electrical connection system and appropriate insulation 11 and also (not shown) on the left of centreline 17. In a preferred design, three insulated 23 ports 24 would be provided all in electrical continuity with each other and with pin 21. Insulation 22 would be provided at the base of pin 21 Ideally pin 12 would be solid and of a size to fit neatly into a terminal I and be securable by a screw 2. As shown, pins 21 could be located either centrally (Fig. 9) or to one side (Fig. 8). Fig. 10 shows the fitting of connection matrices 20, with pins 21 to one side, and a matrix 20A, with a central pin 21, to the rear 26 of a 1 3A power socket. Three ports 24 are preferred to allow for the two ring main conductors R1 and R2 and an optional spur S. Fig. shows the fitting of line, neutral and earth conductors. Fig. 11 shows a sectional elevation of the socket 25, 26 in wall box 27 set into waIl 29. (To avoid confusion, only one matrix connection 20 is shown.) The clearance behind socket 26 is shown 28 as are ring mains R1 and R2 and a spurs.

One feature of the invention is that the pirs 21 on connection matrices 20, 20A may be either at an end (Fig. 8 -either end) or near the centre (Fig. 9) so that the most appropriate one may be chosen according to the location of the terminals 1 on the back of socket 26.

Furthermore, the connection matrices 20 may be rotated about the axis of pin 21 (as shown on the right in Fig. 10) by loosening screw 2, turning the connection matrix 20 to the preferred orientation and re-tightening screw 2. This allows the electrician to make wiring connections, with smooth, gentle curves (as shown in Fig. 11), as opposed to the sharp, U-shaped kinks and wiring jumbles, so often found.

The connection matrices of the invention are currently known as "OW Connectors.

Use of the matrix connectors 20 of the invention will add significantly to the speed of wiring and fitting sockets into wall boxes and potentially increase the reliability of the work by, perhaps, an order of magnitude, with similar reductions in the likelihood of house fires.

S The principle of the invention is applicable to all forms of electrical wiring, e.g. both in power and lighting circuits, and different applications of the principle will be apparent to the skilled person, all falling within the scope of the invention.

Claims

Ciaims:- 1. An electrical power wiring system comprising:-i) an electrical power wall mountable socket; ii) a wall box into which the electrical power socket is securable; iii) an electrical power supply accessible via the wall box; and iv) an electrical power connection having a pin adapted to fit into one of the line, neutral or earth terminals of the socket and also having a plurality of ports each of which ports is in electrical continuity with the other ports and with the pin and into each of which ports a conductor forming part of the electrical wiring system isfiftable;characterised in that the pins of three of the electrical power connections are fitted into the line, neutral and earth terminals of the socket respectively and that the conductors of the wiring system are fitted into appropriate ports on the three connections and that the socket, complete with the three electrical connections and wiring conductors filled therein is secured into the wall box and further characterised in that the dimensions of the electrical power connections when fitted to the socket are fully compatible with the internal size of the wall box so that the socket may be properly secured into the wall box without jeopardising any of the wiring system conductors or their fillings to the ports of the electrical power connections.
2. An electrical power wiring system, as claimed in claim 1, wherein the electrical power socket is a 1 SA power socket.
3. An electrical power wiring system, as claimed in claim 1, wherein the electrical power socket is a 1 3A power socket having a power spur taken therefrom.
4. An electrical power wiring system, as claimed in claim 1, wherein the electrical power socket is a lighting switch.
5. An electrical power wiring system, as claimed in claim 1, wherein the electrical power socket is a multi-way lighting switcit
6. An electrical power wiring system, as claimed in any preceding claim, wherein the wall box is a standard size unit for power or lighting applications.
7. An electrical power wiring system, as claimed in any preceding claim, wherein a part of the pin is electrically insulated. a8. An electrical power wiring system, as claimed in any preceding claim, wherein the electrical power connections are provided with three ports.9. An electrical power wiring system. as claimed in claims 7 and /or8, wherein the pin is located near one end of the plurality of three ports.10. An electrical power wiring system, as claimed in claims 7 and I or 8, wherein the pin is located centrally or towards the centre of the plurality of three ports.11. An electrical power wiring system, as claimed in claims 9 or 10, wherein each of the ports is provided with a quick electrical connection means so that the bared conductor has only to be inserted into the port and pushed in for it to be held permanently fast and in electrical continuity with the rest of the e!ectrical power connection.12. An electrical power wiring system, as claimed in claim 11, wherein the electrical power connection is provided with electrical insulation in appropriate places.13. An electrical power wiring system, as claimed in claim 12, wherein the quick electrical connection, once made, is maintenance-free 14. An electrical power wiring system, as claimed in claim 13, wherein the conductors of the wiring system include line ring main in & line ring main out and neutral ring main in & neutral ring main out and earth ring main in & earth ring main out for each of the line, neutral and earth terminals on the socket.15. An electrical power wiring system, as claimed in claim 13, wherein the conductors of the wiring system include line ring main in & line ring main out and neutral ring main in & neutral ring main out and earth ring main in & earth ring main out for each of the line, neutral and earth terminals on the socket and a spur.16. An electrical power wiring system, as described in and by the above statement, with reference to Figs. 8-1 1.