Electrical outlet front plate

Abstract

An electrical outlet front plate 301, comprising supply terminals 121, 122, 123, for connection to a ring circuit 111, 112, 113, a live supply terminal 121, a neutral supply terminal 122, and a ground

Description

Field of the Invention The present invention relates to electrical outlet front plates and the wiring thereof in domestic and commercial electricity supply systems. Background In domestic and commercial electrical systems, power from the mains supply (the grid) is received at a consumer unit. This consumer unit (also known as a distribution board, fuse board, or fuse box) distributes electricity to individual circuits around a property. Typically, these circuits will connect to appliances (machines that consume electricity) and / or to electrical outlets (also known as sockets) to which other electricity-consuming devices can be connected. The consumer unit will typically have at least 1 fuse or circuit breaker that regulates the flow of power into these circuits and can be used to reversibly disconnect the connection to the connected circuits. With respect to a given point of the circuit, the electrical connection from the mains (e.g. via the consumer unit) is referred to generally as the “supply”, while the downstream use of electricity with respect to the consumer unit is referred to as the “load”. Circuits from the consumer unit typically either a radial circuit or part of a ring circuit. In a radial connection, the appliances or electrical outlets are connected in a line with the consumer unit at one end. It is common for appliances with high power usage (such as an oven) to have its own radial circuit to reduce the risk of overloading the circuit from excessive power draw from multiple appliances. In a ring circuit, which is commonly used in the United Kingdom, the appliances and electrical outlets are connected in a ring Joined to the consumer unit. Appliances and outlets in a radial circuit or a ring circuit are generally connected in parallel. Also, in a ring circuit, the appliance and outlets are connected to the consumer unit’s live terminals (the high voltage terminal) from two different wires. This reduces the thickness of each wire needed to deliver a given amount of power. In a ring circuit, it is possible to create a further connection from a connected appliance or outlet on the ring circuit which is only connected to the ring circuit via a single set of wires. This is known as a spur. This technique allows one to add new connections more easily to the ring circuit without having to rewire other parts of ring circuit in order to maintain the ring arrangement. However, as the new connection is only connected to the ring circuit via a single set of wires, it is generally recommended (and required under some electrical wiring regulations) to include an overcurrent protection device (such as a fuse or a circuit breaker) on the spur in order to reduce the risk of overloading the spur through drawing excessive current. When installing a further outlet then an electrical will typically take a connection from an existing socket and provide this to an FCU, or fused connection unit. This fused connection unit is typically installed on a wall proximal to the supply socket, and then a further connection is taken from the FCU and provided to the further outlet. This requires a significant level of work to be undertaken. Summary of the Invention In accordance with a first aspect of the invention, there is provided an electrical outlet front plate, the electrical outlet front plate comprising: supply terminals, for connection to a ring circuit, comprising: a live supply terminal, a neutral supply terminal, and a ground supply terminal; overcurrent protection device terminals for connecting to an overcurrent protection device; appliance terminals, for providing power to an appliance; and load terminals, for providing power to a further electrical outlet, comprising: a live load terminal, a neutral load terminal, and a ground load terminal; wherein the supply terminals are connected to the appliance terminals to allow electrical power to flow from the supply terminals to the appliance terminals; wherein the live supply terminal is connected to the live load terminal via the overcurrent protection device terminals when an overcurrent protection device is connected therebetween, and wherein the connection between the supply terminals and the load terminals runs in parallel to the connection between supply terminals and the appliance terminals. Advantageously, the outlet comprises separate load terminals protected by an overcurrent device to facilitate forming a spur to connect further outlets. Typically, a user would need to rewire the ring circuit to add a fused connection unit (also known as a fused spur) onto the ring circuit to then safely add further outlets connected to the spur. The outlet of the invention integrates fused Junction circuitry so that a separate fused spur is not necessary. This is particularly advantageous when a user is setting up a ring circuit. The user can use outlets according to the invention in place of conventional outlets, or in locations on the ring circuit where the addition of a spur is more likely. At a later time, if the user wishes to add an outlet, they can spur from the load terminals of outlet of the invention without any additional work, such as rewiring the ring circuit to add a fused spur. As such, this allows a user to add new connections more easily to the ring circuit without having to rewire other parts of the ring circuit in order to maintain the ring arrangement. The electrical outlet front plate may have any one, or any combination insofar as they are compatible and not explicitly excluded, of the optional features set out herein. The electrical outlet front plate may further comprise an overcurrent protection device connected between the overcurrent protection device terminals such that the live supply terminal is connected to the live load terminal via the overcurrent protection device. It should be understood that the neutral supply terminal and neutral load terminal may be provided by a single terminal, which may be referred to as a shared neutral terminal. Similarly, the ground supply terminal and the ground load terminal may be provided by a single terminal, which may be referred to as a shared ground terminal. Once installed, then the shared neutral terminal may simultaneously provide a neutral connection from the ring circuit to both the appliance terminals of the electrical outlet front plate and the neutral supply terminal of a further electrical outlet front plate. Similarly, the shared ground terminal may simultaneously provide a ground connection from the ring circuit to both the appliance terminals of the electrical outlet front plate and the ground supply terminal of a further electrical outlet front plate. It should also be understood that the live load terminal and one of the overcurrent protection device terminals may be provided by a single terminal, which may be referred to as a load-side overcurrent protection terminal. The overcurrent protection device may be a fuse, a circuit breaker, a current limiter, or a residual-current device with overcurrent protection (RCBO). A fuse is preferred as it a small and low cost means to protect a circuit from excessive current draw. However, it may be desired to have a more robust or resettable system for the spur, which may warrant a circuit breaker device, or new wiring solutions. The fuse can conform to British Standard BS1362. The fuse may have an amp rating of 1, 3, 5, 10, or 13 amps. The selection of the fuse is typically dependant on the current draw of the intended appliance or use. The front plate may further comprise an appliance isolator switch operable to reversibly disconnect the supply terminals from the appliance terminals. A switch is a useful feature to cut power to the appliance terminals. This allows a user to turn off an appliance that does not have its own switch, without having to unplug the appliance. It also allows the user to make the switch safer, by ensuring that power is not delivered to the appliance when it is not desired (e.g. when the appliance is potentially dangerous in use, such as a power tool). The appliance terminals may be located within a socket for connection with an electrical plug. The appliance terminals may be available such as for directly receiving a wired connection from the appliance. The front plate may be a flex outlet, in that the applicant terminals may be located on a reverse side of the front plate and suitable for directly wiring to an appliance (for example a water heater, or oven). Many appliances come with a removable plug which can be inserted into a compatible socket. The appliance terminals taking the form of this socket makes the outlet compatible with this kind of removable connection. The front plate may comprise a plurality of sets of appliance terminals, wherein each set of appliance terminals is connected to the supply terminals. Having multiple sets of appliance terminals permits the connection of multiple appliances without having to set up multiple outlets individually. Outlets are commonly referred to as having a number of “gangs” to represent the number of connection points. The front plate may comprise a plurality of appliance isolator switches, wherein each isolator switch is operable to disconnect reversibly the supply terminals from a respective set of appliance terminals. Advantageously, this allows the user to disconnect power to each set of the appliance terminals individually. The front plate may comprise a load isolator switch operable to reversibly disconnect at least the live supply terminal from the live load terminal. Advantageously, this allows the user to disconnect the power supply to the load terminals, thereby also disconnecting any outlets connected to the load terminals. This also may permit the user to connect or disconnect a further outlet from the outlet of the invention. The load isolator switch may also disconnect the ground and / or neutral supply terminals from the ground and neutral load terminals. The load isolator switch may be a double pole switch which isolates the live and neutral supply terminals. The load isolator switch may additionally operate to reversibly disconnect the supply terminals from the overcurrent protection device. Advantageously, this allows the user to disconnect the overcurrent protection device from the power supply. This can be useful for allowing the user to replace or otherwise perform maintenance on the overcurrent protection device or the further outlet connection thereto. In the example of a fuse, it allows the user to easily remove and replace a blown fuse in the outlet. The front plate may further comprise a wireless connectivity module, configured to reversibly disconnect one or both of the supply terminals from the appliance terminals and the supply terminals from the load terminals, in response to a signal received at the wireless connectivity module from an external device. Advantageously, this allows the user to connect or disconnect power to the appliance remotely. This can be particularly useful when the outlet is in a remote part of the ring circuit or if the user wishes to operate the appliance from a remote location. The connection between components may be in the form of wires or bus bars. The front plate may have a forward side comprising the appliance terminals, and a reverse side comprising the supply terminals and the load terminals, wherein the front plate has a coverable recess on the forward side for receiving the overcurrent protection device. Advantageously, the connection points are on the reverse side of the front plate such that they will be within the housing when the front plate is installing into a backing box. As such the connection points, which will be live during use, are protected from outside access. By contrast the appliance terminals, which need to be accessed for connection to an appliance are accessible from the outside of the housing when the front plate is installed into the backing box. The overcurrent protection device may only be accessible from the reverse side of the front plate. As such, when the front plate is installed, the overcurrent protection device is inside the outlet and cannot be accessed without first removing the front plate from the outlet. The front plate may further comprise a rectifier, and a DC output socket. The DC output socket may be a universal serial bus port. Advantageously, having a rectifier to convert AC voltage from the mains supply to DC voltage, which can then be supplied by an alternative socket on the front plate, removes the need to have an external rectifier powered from the appliance terminals, taking up a connection that could be used by other appliances. The supply terminals may be connected to the appliance terminals via a surge protection device, preferably a metal oxide varistor, or a gas discharge arrestor. Advantageously, a surge protection device protects the outlet and any connected appliances from increases in voltage beyond that expected from the mains supply. Such devices typically route excess voltage to the ground. The front plate may have ingress protection (e.g. an IP rating) for preventing water or dust from entering the outlet in use. Advantageously, this improves the safety of the device making it suitable for use in outdoor environments or other situations where there is a risk of unwanted material entering the outlet and potentially causing an electrical short. For example, this can be useful for powering garden lights or a pump for a pond. The front plate may further comprise a dimmer switch to limit energy supply to the appliance terminals. Advantageously, some appliances may benefit from intensity control which can be modulated by reducing the voltage or current delivered to the appliance. Such devices include lights or fans. A dimmer switch on the outlet permits this modulation without requiring a dimmer on the appliance itself. In accordance with a second aspect of the invention, there is provided a method for installing an electrical outlet front plate according to the first aspect, wherein the method comprises: connecting the supply terminals to a ring circuit, and installing the front plate into a housing. The housing may comprise an electrical outlet backing box. The method may further comprise a step of fitting an overcurrent protection device between the overcurrent protection device terminals. The electrical outlet front plate as referenced in the second aspect may have any one, or any combination insofar as they are compatible and not explicitly excluded, of the optional features as set out with reference to the first aspect. In accordance with a third aspect of the invention, there is provided a method for installing a load-side electrical outlet, wherein the method comprises connecting supply terminals of the load-side electrical outlet to the load terminals of an electric outlet front plate according to the first aspect. Advantageously, the method allows the load-side electrical outlet to be connected as a spur from the ring circuit without requiring rewiring the ring circuit to add an overcurrent protected junction (a fused spur) to limit the potential current draw of the spur. This reduces the cost and complexity of adding outlets as spurs after the ring circuit has been completed. The electrical outlet front plate as referenced in the third aspect may have any one, or any combination insofar as they are compatible and not explicitly excluded, of the optional features as set out with reference to the first aspect. Therefore the invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided. Summary of the Figures Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which: Figure 1 shows an electrical outlet of the prior art wired to a ring circuit; Figure 2 shows two electrical outlets of the prior art. The first outlet is wired to a ring circuit and the second outlet is wired to the first outlet in a spur arrangement; Figure 3 shows an electrical outlet according to the invention, wired to a ring circuit; Figure 4 shows a double electrical outlet according to the invention, wired to a ring circuit; Figure 5 shows an electrical outlet according to the invention, wired to a ring circuit, and to a further electrical outlet in a spur arrangement; and Figure 6 shows a variant electrical outlet according to the invention wired to a ring circuit and to a further electrical outlet in a spur arrangement. Detailed Description of the Invention Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. Figure 1 shows an electrical outlet 101 of the prior art. It comprises supply terminals 121, 122, 123 which respectively connect to the wires of the ring circuit 111, 112, 113. There are three supply terminals, the live supply terminal 121 which connects to the live wire of the ring circuit 111, the neutral supply terminal 122 which connects to the neutral wire 112, and the ground supply terminal 123 which connects to the ground wire 113. The supply terminals 121,122,123 then connect to the appliance terminals 121,122, 123. The appliance terminals comprise a live appliance terminal 141, a neutral appliance terminal 142, and a ground appliance terminal 143. These are connected to the live supply terminal 121, the neutral supply terminal 122, and the ground supply terminal 123 respectively. The appliance terminals 121, 122, 123 are contained with a socket to facilitate the connection of an electrical plug (not shown) of an appliance. However, electrical appliances may be wired directly to the appliance terminals, if a more permanent connection is desired. Figure 2 shows a first electrical outlet of the prior art 101a connected in a spur arrangement to a second outlet 101b. In particular, the supply terminals of the first outlet 121a, 122a, 123a are connected to the supply terminals of the second outlet 121b, 122b, 123b via a set of wires 261. In this way, a parallel connection is established between the ring circuit 111, 112, 113, the first outlet 101a, and the second outlet 101b. However, the connection between the first outlet 101a and the ring circuit 111, 112, 113 is such that the first outlet 101 a is connected via two wires for each supply terminal 121a, 122a, 123a, which then return to the consumer unit. The first outlet 101a is thereby part of ring circuit. Whereas for the second outlet 101b, only a single wire connects each supply terminal 121 b, 122b, 123b to the ring circuit 111, 112, 113. The second outlet 101 b is thereby not considered to be on the ring circuit but is instead part of a spur from the ring circuit. Figure 3 shows an electrical outlet according to a first aspect of the invention 301. This outlet partially corresponds to the outlet of the prior art 101, in that it comprises supply terminals 121, 123, 123 and appliance terminals 141, 142, 143, and is connected to a ring circuit 111,112, 113. It further comprises load terminals 351, 352, 353, suitable for receiving a connection to a further electrical outlet. The load terminals comprise a live load terminal 351, a neutral load terminal 352, and a ground load terminal 353. These are each connected to the live 121, neutral 122, and ground 123 supply terminals respectively. The live supply terminal 121 is connected to the live load terminal 351 via a fuse 331 (a form of overcurrent protection device). The fuse could be replaced with a circuit breaker, a current limiter, a residual-current device with overcurrent protection (RCBO), or some other overcurrent protection device. The fuse may be located in a recess of the electrical outlet front plate having overcurrent protection device terminals 321a and 321 b for connecting to the fuse (or other overcurrent protection device), so that a fuse of desired current limit can be installed or so that the outlet can be sold without a fuse, to be instead supplied by the user. In this outlet, the connection between the supply terminals 121, 122, 123 and the load terminals 351, 352, 353 runs in parallel to the connection between the supply terminal 121, 122, 123 and the appliance terminals 141, 142,143. Figure 4 shows a further embodiment of an outlet according to the invention 401. In this embodiment, the outlet comprises a first set of appliance terminals 141a, 142a, 143a and a second set of appliance terminals 141 b, 142b, 143b. Both sets of appliance terminals are connected in parallel to the supply terminals 121, 122, 123. The supply terminals 121, 122, 123 are connected to the load terminals 351, 352, 353 in the same way as in Figure 3. Figure 5 shows a first electrical outlet according to the first aspect of the invention 301. In Figure 5, a second electrical outlet of the prior art 101 b is connected in a spur arrangement to the first outlet 301. In particular, the load terminals of the first outlet 351, 352, 353 are connected to the supply terminals of the second outlet 121b, 122b, 123b via a set of wires 561. In this way, the second outlet 101b is connected to the ring circuit 111,112, 113, via the load terminals of the first outlet 351, 352, 353, and in particular the live supply terminal of the second outlet 121b receives power from the live ring circuit wire 111 via the fuse 331. As a result, the electrical supply of the second outlet 101b is protected from excessive usage by the fuse 331. As discussed previously, it should be understood that the neutral load terminal 352 and ground load terminal 353 can be provided by the neutral supply terminal 122 and the ground supply terminal 123 respectively in that a further electrical outlet front plate may connect directly to the neutral supply terminal 122 and the ground supply terminal 123. This is shown in Figure 6 where like features are indicated by like reference numerals. The live load terminal 351 is distinct from the live supply terminal 121, as the live load terminal 351 is protected by the overcurrent protection device. However the live load terminal 351 may, in some examples, be provided by the overcurrent protection device terminal 321b which may be referred to as a load-side overcurrent protection terminal. The further electrical outlet front plate would connect directly to the load-side overcurrent protection terminal 321b. Whilst not shown, the electrical outlet front plate may include one or more isolators. For example the electrical outlet front plate may include an appliance isolator switch which can be used to disconnect the supply terminals from the appliance terminals. Similarly, the electrical outlet front plate may include a load isolator switch which can be used to disconnect at least the live supply terminal from the live load terminal. In some examples the load isolator switch may isolate each of the live, ground, and neutral supply terminals from the live, ground, and neutral load terminals. The isolators may be rocker switches of the type known per se in the art. The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof. While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Particularly those arrangements which have an identical electrical topology to those arrangements explicitly disclosed herein. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention. For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations. Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described. Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. It must be noted that, as used in the specification and the appended claims, the singular forms “a," “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about’ one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / -10%.

Claims

1. An electrical outlet front plate comprising:supply terminals, for connection to a ring circuit, comprising:a live supply terminal, a neutral supply terminal, and a ground supply terminal;overcurrent protection device terminals for connecting to an overcurrent protection device; appliance terminals, for providing power to an appliance; andload terminals, for providing power to a further electrical outlet, comprising:a live load terminal, a neutral load terminal, and a ground load terminal;wherein the supply terminals are connected to the appliance terminals to allow electrical power to flow from the supply terminals to the appliance terminals;wherein the live supply terminal is connected to the live load terminal via the overcurrent protection device terminals when an overcurrent protection device is connected therebetween, andwherein the connection between the supply terminals and the load terminals runs in parallel to the connection between supply terminals and the appliance terminals.

2. The electrical outlet front plate of any preceding claim, wherein the front plate further comprises an overcurrent protection device connected between the overcurrent protection device protection terminals such that the live supply terminal is connected to the live load terminal via the overcurrent protection device.

3. The electrical outlet front plate of claim 1, wherein the overcurrent protection device is a fuse, a circuit breaker, a current limiter, or a residual-current device with overcurrent protection (RCBO).

4. The electrical outlet front plate of any preceding claim, wherein the front plate further comprises an appliance isolator switch operable to reversibly disconnect the supply terminals from the appliance terminals.

5. The electrical outlet front plate of any preceding claim, wherein the appliance terminals are located within a socket for connection with an electrical plug.

6. The electrical outlet front plate according to claim 5, wherein the front plate comprises a plurality of sets of appliance terminals, wherein each set of appliance terminals is connected to the supply terminals.

7. The electrical outlet front plate according to claim 6, wherein the front plate comprises a plurality of appliance isolator switches, wherein each isolator switch is operable to disconnect reversibly the supply terminals from a respective set of appliance terminals.

8. The electrical outlet front plate according to any preceding claim, wherein the front plate comprises a load isolator switch operable to reversibly disconnect at least the live supply terminal from the live load terminal.

9. The electrical outlet front plate according to claim 8, wherein the load isolator switch additionally is operable to reversibly disconnect the supply terminals from the overcurrent protection device terminals.

10. The electrical outlet front plate according to any preceding claim, wherein the front plate further comprises a wireless connectivity module, configured to disconnect reversibly the supply terminals from the appliance terminals in response to a signal received at the wireless connectivity module from an external device.

11. The electrical outlet front plate according to any preceding claim, wherein the connection between components is in the form of wires or bus bars.

12. The electrical outlet front plate according to any preceding claim, wherein the front plate has a forward side comprising the appliance terminals, and a reverse side comprising the supply terminals and the load terminals, wherein the front plate has a coverable recess on the forward side for receiving the overcurrent protection device.

13. The electrical outlet front plate according to any preceding claim, wherein the front plate further comprises a rectifier, and a DC output socket, preferably wherein the DC output socket is a universal serial bus port.

14. The electrical outlet front plate according to any preceding claim, wherein the supply terminals are connected to the appliance terminals via a surge protection device, preferably a metal oxide varistor, or a gas discharge arrestor.

15. The electrical outlet front plate according to any preceding claim, wherein the front plate further comprises a dimmer switch to limit energy supply to the appliance terminals.

16. A method for installing an electrical outlet front plate according to any one of claims 1 to 14, wherein the method comprises:connecting the supply terminals to a ring circuit, and installing the front plate into a housing.

17. The method according to claim 15, wherein the housing comprises an electrical outlet backing box.

18. The method according to claim 16 or 17, further comprising fitting an overcurrent protection device between the overcurrent protection device terminals.

19. A method for installing a load-side electrical outlet, wherein the method comprises connecting supply terminals of the load-side electrical outlet to the load terminals of an electric outlet front plate according to any one of claims 1 to 14.

Images