GB2446841A

GB2446841A - Split load distribution board/consumer unit

Info

Publication number: GB2446841A
Application number: GB0703647A
Authority: GB
Inventors: Prem Singh
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-02-26
Filing date: 2007-02-26
Publication date: 2008-08-27
Also published as: WO2008104743A1; GB0703647D0

Abstract

A consumer unit has an isolator 6, a residual current device (RCD) 8, a first bus bar 26 connected to the isolator and a second bus bar 28 connected to the RCD. Switches 30 allow circuit breakers (eg Miniature Circuit Breakers, MCBs) to be connected to either of these bus bars. The bus bars may form a multi layer stack, and the terminals may be colour coded.

Description

DISTRIBUTION BOARD

The present invention relates to a distribution board in which is mounted a plurality of circuit breakers, and in particular to a split load distribution load.

Dstributjon boards are also known as circuit breaker panels, fuse boxes or consumer units. They are generally found in central locations within buildings and often serve as the point at which electricity is distributed to a plurality of downstream circuits within a building from an upstream cable supplying electricity into the building. Distribution boards generally house a plurality of electrical circuit breakers, each of which connects the upstream cable to a downstream circuit. Circuit breakers are automatically and manually automated switches designed to automatically disconnect so as to protect a downstream electrical circuit from damage caused by an overload and/or a short circuit. The circuit breakers can then be re-connected manually, generally by flicking a manual switch actuator.

Distribution boards and their associated circuit breakers are made in varying sizes and capacities, ranging from those used in domestic households to those used in industrial applications. A common form of circuit breaker used in domestic applications is a miniature circuit breaker or MCB.

Distribution boards generally include an isolator switch between the upstream cable and all of the circuit breakers of the distribution board. This enables the supply of electricity to the distribution board to be interrupted, for example, during maintenance of the distribution board.

Many distribution boards, also include a residual current device or RCD, which is a device that disconnects a downstream circuit when it detects that the flow of current between the live conductor and the neutral conductor in the circuit is not balanced. This imbalance of current could represent leakage through the body of a person who is grounded and touching an energised part of the circuit, which can result in a lethal electric shock. An RCD is generally required in addition to the circuit breakers and so is typically wired into the distribution board between the isolator switch and one or more circuit breakers. Typically, only some of the downstream circuits require connection via an RCD, for example to circuits supplying appliances in an environment including water, such as outdoor areas, bathrooms, kitchens, swimming pools, etc. Distribution boards in which some circuits are connected via an RCD and some are not are known as split load distribution boards. If all of the downstream circuits are connected to the upstream supply cable via an RCD then any electrical fault will cause power to be cut to the entire building, including lighting circuits, freezers and fire alarms. Before wiring such known distribution boxes, it is necessary to decide which downstream circuits require RCD protection because subsequent re-wiring of the distribution board is a costly and time consuming process. This can become a problem, for example, if a building is extended or parts of the building change their use from or to an environment including water. *

Most currently used distribution boards comprise circuit breakers that are wired directly to the downstream circuits. Also, the live and neutral wires of the supply cable are directly wired into the isolator switch. This requires the stripping down of electrical cables to expose the indMdual wires (live, neutral and earth) and the stripping down of each wire and the connection of each wire to the appropriate terminal of the appropriate component within the distribution box. This is painstaking work, which has to be accurately and neatly carried out and then has to be checked for conformance.

Distribution boards are advantageously designed with a degree of flexibility, so that for different buildings, different downstream circuits can be connected to the supply cable via an RCD and so that over time changes of use of buildings can be accommodated in the distribution board.

A first aspect of the present invention aims to overcome at least some of the problems set out above by providing a split load distribution box, comprising a plurality of components including at least one circuit breaker, an isolator switch, a residual current device, an input for connection within an upstream supply circuit and at least one output for connection within an associated downstream circuit, and additionally comprising a multi-layered bus bar assembly including a stack of substantially planar bus bars pre-configured to make connections between the components. The bus bar assembly improves ease of assembly in a pre-configured distribution box and enables a compact design in which mis-connection of components within the distribution box is avoided. Also, the distribution board according to the present invention can be fitted and wired in a fraction of the time it takes to wire a conventional distribution board. When installing a distribution box according to the present invention, there is no need to cut bus bars to shape. In addition, inspection and fault finding is improved, when compared to a conventional distribution board.

The stack may include a substantially planar Jive bus bar configured to make live connections between the components and a substantially planar neutral bus bar configured to make neutral connections between the components. In addition, a third substantially planar earth bus bar configured to make earth connections between the input and output may be included in the stack.

To avoid a short circuit within the bus bar assembly each bus bar may be coated with an insulating layer. In this case the coated bus bars may be stacked within an inner housing of the distribution box to form the multi-layered bus bar assembly. Alternatively, each bus bar may be embedded within an insulating plate or layer and the insulating plates or layers may be stacked to form the multi-layered bus bar assembly. As an additional alternative, the multi-layered bus bar assembly may comprise a stack of bus bars interspersed by insulating plates or layers.

In a distribution box the circuit breakers are arranged, optionally with the isolator switch and/or the RCD, in at least one block. The or each block may include socket blocks into which circuit breakers can be plugged so as to enable interchangeable plug in miniature circuit breakers (MCBs) to be

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positioned as desired. The whole or part of the multi-layered bus bar assembly may be shaped to fit beneath the or each block and may be suitably shaped to fit beneath the or each block. Then the bus bar assembly, including pre-configured bus bars, can be fitted beneath the block so as to correctly position terminations of the bus bars in relation to the components of the distribution box. The multi-layered bus bar assembly may comprise a single stack of bus bars.

The input may comprise a pair of connectors, such as a pair of terminal blocks, and the output may comprises at least one pair of connectors, such as a pair of terminal blocks and the multi-layered bus bar assembly may be conveniently configured to at least partially house the connectors. Each terminal block houses the live, neutral and earth connection for either an input supply or a downstream circuit, thus further simplifying the wiring as compared to a conventional distribution board as the live, neutral and earth are housed together ergonomically and there is no need to feed individual wires around. With the present invention there is no time consuming need to shape wires for neatness and a professional finish is easier to achieve.

According to a second aspect of the present invention, there is provided a distribution box comprising a plurality of components including at least one circuit breaker, an isolator switch, a residual current device, an input for connection within an upstream supply circuit and at least one output for connection within an associatecj downstream circuit, and additionally comprising a live bus bar configured to make live connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and a neutral bus bar configured to make neutral connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one switch switchable between a first and second position, each switch connecting an associated circuit breaker to the first lines in the first position and to the second lines in the second position. This enables the number of downstream circuits which can be protected via the isolator only and the number of downstream circuits which can be protected by the isolator and RCD to be varied. There is no need to cut or move bus bars to account for changes in the downstream circuits all that is required is to move one or more switches between RCD and isolator switch mode or isolator switch only mode.

A distribution box may be provided which comprises a plurality of components including at least one circuit breaker, an isolator switch, a residual current device, an input for connection within an upstream supply circuit and at least one output for connection within an associated downstream circuit, and additionally comprising: a live bus bar configured to make live connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one live switch switchable between a first and second position, each switch connecting a live connection of an associated circuit breaker to the first line in the first position and to the second line in the second position, and a neutral bus bar configured to make neutral connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one neutral switch switchable between a first and second position, each switch connecting a neutral connection of an associated circuit breaker to the first line in the first position and to the second line in the second position; wherein the live and neutral switches are mechanically linked in the same position as each other.

Again, this enables the number of downstream circuits which can be protected via the isolator only and the number of downstream circuits which can be protected by the isolator and RCD to be varied. The distribution board according to the present invention can be used as a single load system (ie. no RCD connected) as well as a split load system.

A distribution box with such switches may comprise a cover which can be securely fastened over the switches so as to prevent inadvertent movement of the switches between the first and second positions. The distribution box according to the present invention can be provided as a sealed unit, with no need to remove the cover after installation. *

The distribution board according to the present invention also has the advantage of being more compact than conventional fuse boards, thus saving on space in the confined.spaces distribution boards are often located. Parallel terminal blocks may be provided at the top and bottom of the distribution board in order to make wiring easier, depending on which set of terminal blocks is most easily accessible.

The invention will now be described by way of example only and with reference to the accompanying schematic drawings, wherein: Figure 1 shows the configuration of a static split load distribution board according to the present invention; Figure 2 shows the configuration of a live circuit of a flexible split load distribution board according to the present invention; Figure 3 shows the configuration of a neutral circuit of a flexible split load distribution board according to the present invention for use in combination with the live circuit of Figure 2; Figure 4 shows the configuration of an earth circuit for use in combination with the live circuit of Figure 2 and the neutral circuit of Figure 3 in order to form a flexible split load distribution board according to the present invention; Figure 5a shows an array of socket blocks and Figure 5b shows a single socket block and a miniature circuit breaker (MCB) which can be fitted into the socket block, suitable for use in a distribution board according to the present invention; Figure 6 shows a six way split distribution board according to the present invention, showing an array of switches; and Figure 7 shows the distribution board of Figure 6 with a protective cover over the array of switches.

A single phase static split load distribution board is shown in Figure 1 and comprises six circuit breakers (4), an isolator switch (6) and a residual current device (RCD) (8). As an alternative to the circuit breakers (4), a socket block (4c) comprising an array of sockets can be housed in the distribution board into which the circuit breakers (4), for example, miniature circuit breakers (MCBs), can be inserted, as is shown in Figures 5a and 5b and as is well known in the art. The three circuit breakers (4b) to the right of the RCD (8) in Figure 1 are connected to the supply inlet via the isolator (6) and the three circuit breakers (4a) to the left of the RCD (8) in Figure 1 are connected to the supply inlet via the RCD (8) and the isolator (6). Thus, the distribution board of Figure 1 is split load. The distribution board of Figure 1 carries an array of six circuit breakers (4), however, the configuration of Figure 1 can easily be extended to accommodate more circuit breakers, for example a total of eight, ten or twelve circuit breakers, as is well known in the art.

Two rows of terminal blocks (10, 12) are mounted above and below the central block of the circuit breakers (4), isolator switch (6) and RCD (8). Each row includes one of six pairs of output terminal blocks (10) and one of a pair of inlet terminal blocks (12). The three pairs of output terminals (lOa) to the left of Figure 1 are the output terminals for the left hand circuit breakers (4a) connected via the RCD (8) and the three pairs of output terminals (lOb) to the tight in Figure 1 are the output terminals for the right hand circuit breakers (4b) not connected via the RCD (8). Each of the terminal blocks (10, 12) comprises an inner (10', 12') and an outer (10", 12") live, neutral and earth terminal. These terminals are colour coded, for example blue for neutral, brown for live and green and yellow for earth. The live, neutral and earth terminal for each terminal block (10, 12) are housed together, but between each conductor are insulating walls to minimise any contact with each other.

Within an inner housing (2) are housed a live bus bar (14), a neutral bus bar (16) and an earth bus bar (18). The live bus bar (14) connects the live terminals of the pair of input terminal blocks (12) to the isolator switch (6), connects the isolator switch to the RCD (8), connects the isolator switch (6) to the three right hand circuit breakers (4b), the RCD to the three left hand circuit breakers (4a) and connects the six circuit breakers (4) to the live terminals of each output terminal block. The neutral bus bar (16) connects the neutral terminals of the pair of input terminals (12) to the isolator switch (6), connects the isolator switch to the RCD (8) and to the neutral terminals of the right hand output terminals (lOb) and connects the RCD (8) to the neutral terminals of the left hand output terminals (lOa). The earth bus bar (18) connects the earth terminals of the pair of input terminal blocks (12), to the earth terminals of the output terminal blocks (10).

Each bus bar (14, 16, 18) is formed as a substantially planar rack having the configuration shown in Figure 1 and may, for example, be stamped out of a

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metal plate. Each such bus bar is configured to have terminations which connect to the circuit breakers (4), isolator switch (6) and RCD (8) and to the appropriate inner terminals (10', 12') of the terminal blocks (10, 12), as is shown in Figure 1. For example, each inner terminal (10', 12') of the board might have a conducting metal tab clamped within and extending inwardly from it. Then the terminations from the bus bars (14, 16, 18) can be electrically connected, for example, by spot welding to the metal tabs of the corresponding inner terminals of the terminal blocks. The bus bars are described as substantially planar, because parts of the bus bar might extend slightly above or below a main plane of the bus bar, for example to account for the crossing of parts of the bus bars or in order to reach a connection to the inner terminals (10', 12') or to the circuit breakers (4), isolator switch (6) or RCD (8). The bus bars (14, 16, 18) are located and shaped to fit beneath the RCD (8), isolator switch (6) and circuit breakers (4).

The live bus bar (14) may be made, for example, from copper, and the neutral and earth bus bars (16, 18) may be made, for example from a brass/copper alloy.

In one embodiment, the inner housing (2) or multi-layered bus bar arrangement, is formed of at least four, substantially planar layers of insulating material, for example polycarbonate. The three bus bars (14, 16, 18) are each sandwiched between adjacent planar layers of the insulating material so that they are electrically isolated from each other. The planar layers of insulating material and of the bus bars (14, 16, 18) fit beneath the block including the circuit breakers (4), isolator switch (6) and RCD (8). The planar surfaces of the planar layers may also be formed with trackways, within which the adjacent bus bar can fit. In addition, at least some of the planar layers of the inner housing may be formed with cut out portions at their upper and lower edges for supporting the terminal blocks (10, 12).

As a second alternative, each bus bar (14, 16, 18) may be embedded within a planar insulating layer, for example of polycarbonate, with only the terminations of the bus bar exposed. The planar insulating layers, would again be appropriately shaped to fit beneath the RCD (8), isolator switch (6) and the socket blocks (4c) (See Figures 5a and 5b) and to accommodate the terminal blocks (10, 12). The planar insulating layers, would then be stacked, one above the other, within the distribution board to form a multi-layered bus bar assembly. As each insulating layer is added, the terminations of the embedded bus bar are connected to the appropriate terminal of the input/output terminals (10, 12), the circuit breakers (4), isolator switch (6) and RCD (8). Then the next layer is added, until the three stacked layers of the insulating layers each containing one of the live neutral or earth bus bars are fitted within and connected to the components of the distribution board.

As a third alternative, the bus bars (14, 16, 18) are each coated with a thin insulating layer so that only the terminations of the bus bars are not coated.

The inner housing (2) is then formed to receive the three coated bus bars.

The inner housing (2) may, for example, be a clamshell type housing, with the lower part of the clamshell integrally formed with the remainder of a housing of I. the distribution board housing. The lower clamshell may be arranged to accommodate the terminal blocks (10, 12). Then each of the three coated bus bars (14, 16, 18) are layered on top of each other, so that they are each beneath the circuit breakers (4), isolator switch (6) and RCD (8). As each coated bus bar is placed within the lower clamshell, its terminations are electrically connected to the terminal blocks (10, 12), the socket blocks (4c) of the circuit breakers (4) (See Figures 5a and 5b), isolator switch (6) and RCD (8) and then the next bus bar is layered over it. Finally, when each of the bus bars (14, 16, 18) are laid over the lower clamshell and electrically connected, an upper clamshell of the inner housing (2) is laid over the bus bars to cover them and the two clamshells are fixed together, for example by screw threaded connectors. The upper clamshell is shaped to fit around the block and is shaped to cooperate with the lower clamshell, so as to house the terminal blocks (10, 12).

The three alternatives above, provide an easy to manufacture pre-configured split load distribution box, which is compact and relatively simple to install, merely requiring connections between the upstream supple cable wires and an input terminal block (12) and the downstream circuit wires to the output terminal blocks (10). This makes safety inspection of the connected up distribution board less complicated. The inner housing (2) supports and protects the three bus bars (14, 16, 18) and the design of pre-configured bus bars and inner housing ensures that the correct electrical connections are made and maintained between the terminal blocks (10, 12), circuit breakers (4), isolator switch (6) and RCD, improving the safety and longevity of the distribution board.

To install the distribution box of Figure 1 the wire terminations of the electrical input supply cables are connected to the corresponding outer terminals (12") of the one of the pair of input terminal blocks. The wire terminations of each downstream circuit cable are connected to the corresponding outer terminals (10") of one of an opposing pair of the output terminal blocks (10).

Downstream circuits requiring RCD protection are connected to the output terminal blocks (ba) and downstream circuits not requiring RCD protection are connected to the output terminal blocks (lOb).

The embodiment of Figure 1 has several advantages over prior art distribution boards, in particular ease of manufacture.

Where a house is altered or extended so that the overall number of circuit breakers (4) or the number of circuit breakers (4) requiring connection via the RCD (8) changes, this eventuality can be accommodated by, using a distribution board according to Figure 1 with the capacity to hold and connect more circuit breakers than are originally required on installation of the distribution board. For example, a split load distribution board for eight circuit breakers, might initially be used in a building having only six downstream circuits. Then as additional circuits subsequently arise, they can be connected in to the existing distribution board.

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* A further embodiment of the present invention is shown in Figures 2 to 4, * which builds in added flexibility to the split load distribution board of Figure 1.

Like parts of the Figures are shown by like numerals and the live bus bar of Figure 2, neutral bus bar of Figure 3 and earth bus bar of Figure 4 are stacked as is described above in relation to Figure 1 to form a distribution board similar to that of Figure 1, but with the improvements described below.

As with the Figure 1 embodiment, the live bus bar (14) (Figure 2), neutral bus bar (16) (Figure 3) and earth bus bar (18) (Figure 4) are stacked in a multi-layered bus bar assembly indicated by inner housing (2).

The live bus bar (14) of Figure 2 connects the live terminals of the pair of input terminal blocks (12) to the isolator switch (6), connects the isolator switch to the RCD (8) and each of the circuit breakers (4) to either the RCD (8) or to the isolator switch (6) and connects the six circuit breakers (4) to the live terminals of each output terminal block (10). Each circuit breaker (4) can be connected either directly to the isolator switch (6) via a first line (20) of the live bus bar (14) or connected to the isolator switch (6) via the RCD (8) via a second line (22) of the live bus bar (14) running parallel to the first line (20). A slider switch (24) is provided for each circuit breaker (4) for connecting the circuit breaker (4) to the first line (20) in a first position of the slider switch (24) (shown in dotted lines in Figure 2) and for connecting the circuit breaker (4) to the second line (22) in a second position of the slider switch (24) (shown in full lines in Figure 2).

The neutral bus bar (16) of Figure 3 connects the neutral terminals of the pair of input terminals (12) to the isolator switch (6), connects the isolator switch to the RCD (8) and connects the neutral terminals of the output terminals (10) either directly to the isolator via a first line (26) of the neutral bus bar (16) or to the isolator via the RCD (8) via a second line (28) of the neutral bus bar (16).

The first (26) and second (28) lines of the neutral bus bar. (16) run parallel to each other. A slider switch (30) is provided for each circuit breaker (4) for connecting the circuit breaker (4) to the first line (26) in a first position of the slider switch (30) (shown in dotted lines in Figure 3) and for connecting the circuit breaker (4) to the second line (28) in a second position of the slider switch (30) (shown in full lines in Figure 3).

The earth bus bar (18) of Figure 4 connects the earth terminals of the pair of input terminal blocks (12), to the earth terminals of the output terminal blocks (10).

For each circuit breaker (4), the slider switch (24) for the live bus bar (14) associated with a circuit breaker (4) is paired up with the slider switch (30) for the neutral bus bar (16) for that same circuit breaker and each such pair of switches (24, 30) are mechanically linked. In this way the switches (24, 30) of a linked pair of switches, are either both in the first position or both in the second position. Therefore, by positioning the linked pairs of slider switches (24, 30) into either the first position or the second position, each downstream circuit connected to the distribution board can be connected to the upstream supply via the isolator switch (6) only (first position) or via the isolator switch * (6) and the RCD (8) (second position). This provides significant versatility as * compared to the distribution board described above in relation to Figure 1. A secure housing (32) in addition to the inner housing (2) is used to cover the slider switches (24, 30) in order to prevent inadvertent switching of the slider switches between the first and second positions. The secure housing can be securely connected to the distribution board or inner housing (2), for example, via screw threaded connectors.

The arrangement described above in relation to Figures 1 to 4 can also be adapted for use in three phase distribution boxes, where split loads are required.

Figure 6 shows a six way split distribution board according to the present invention, with the inner housing (2) hiding the bus bars (14, 16, 18). The distribution board of Figure 6 is similar to that of Figures 2 to 4, with like parts of Figure 6 identified by the same reference numerals used in the other Figures. Each switch (24) of the live bus bar (14) (Figure 2) and the corresponding switch (30) of the neutral bus bar (30) is mechanically linked to a corresponding one of a series of slider switches (40). Where one of the switches (40) is moved upwardly to cover the corresponding space (42), the associated switches (24, 30) are connected to their respective isolator and RCD lines (20, 28). Where one of the switches in moved downwardly to cover the corresponding space (44), the associated switches (24, 30) are connected to their respective isolator switch only lines (22, 26).

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Figure 7 shows the distribution board of Figure 6 with a cover (46), fixed over the array of slider switches (40). The cover (46) can be fixed in place to the * distribution board by a plurality of screw fixing (48). These screw fixings may require a dedicated tool for thier fixing and removal so as to prevent unauthorised removal of the cover (46). Figure 7 also illustrates a pair of covers (52) for the output and input connection and a transparent cover (50) for the block including the circuit breakers (4), isolator switch (6) and RCD (8).

Claims

1: A split load distribution box, comprising a plurality of components including at least one circuit breaker, an isolator switch, a residual current device, an input for connection within an upstream supply circuit and at least one output for connection within an associated downstream circuit, and additionally comprising a multi-layered bus bar assembly including a stack of substantially planar bus bars pre- configured to make connections between the components.

2. A distribution box according to claim I wherein the stack includes a planar live bus bar configured to make live connections between the components and a planar neutral bus bar configured to make neutral connections between the components.

3. A distribution box according to claim 2 additionally including a planar earth bus bar configured to make earth connections between the input and output.

4. A distribution box according to any one of the preceding claims wherein each bus bar is coated with an insulating layer.

5. A distribution box according to claim 4 wherein the coated bus bars are stacked within an inner housing of the box to form the multi-layered bus bar assembly.

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6. *A distribution box according to any one of claims I to 3 wherein each bus bar is embedded within an insulating layer and the insulating layers are stacked to form the multi-layered bus bar assembly.

7. A distribution box according to any one of claims I to 3 wherein the multi-layered bus bar assembly comprises a stack of bus bars interspersed by insulating layers.

8. A distribution box according to any one of the preceding claims wherein the circuit breakers are arranged in at least one block and the multi-layered bus bar assembly is shaped to fit beneath the or each block.

9. A distribution box according to any one of the preceding claims wherein the multi-layered bus bar assembly comprises a single stack of bus bars.

10. A distribution box according to any one of the preceding claims wherein the input comprises a pair of connectors and the output comprises at least one pair of connectors and wherein the multi-layered bus bar assembly is configured to at least partially house the connectors.

11. A distribution box according to any one of the preceding claims comprising a live bus bar configured to make live connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and a neutral bus bar configured to make neutral connections between the

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components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one switch switchable between a first and second position, each switch connecting an associated circuit breaker to the first lines in the first position and to the second lines in the second position.

12. A distribution box according to any one of the preceding claims comprising: a live bus bar configured to make live connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one live switch switchable between a first and second position, each switch connecting a live connection of an associated circuit breaker to the first line in the first position and to the second line in the second position' and a neutral bus bar configured to make neutral connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one neutral switch switchable between a first and second position, each switch connecting a neutral connection of an associated circuit breaker to the first line in the first position and to the second line in the second position; wherein the live and neutral switches are mechanically linked in the same position as each other.

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13. A distribution box according to claim 11 or claim 12 comprising a cover which can be securely fastened over the switches.

14. A distribution box comprising a plurality of components including at least one circuit breaker, an isolator switch, a residual current device, an input for connection within an upstream supply circuit and at least one output for connection within an associated downstream circuit, and additionally comprising a live bus bar configured to make live connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and a neutral bus bar configured to make neutral connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one switch switchable between a first and second position, each switch connecting an associated circuit breaker to the first lines in the first position and to the second lines in the second position.

15. A distribution box comprising a plurality of components including at least one circuit breaker, an isolator switch, a residual current device, an input for connection within an upstream supply circuit and at least one output for connection within an associated downstream circuit, and additionally comprising: a live bus bar configured to make live connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one live switch switchable between a first and * second position, each switch connecting a live connection of an * associated circuit breaker to the first line in the first position and to the second line in the second position, and a neutral bus bar configured to make neutral connections between the components, comprising a first line connected to the isolator switch and a second line connected to the isolator switch via the residual current device and at least one neutral switch switchable between a first and second position, each switch connecting a neutral connection of an associated circuit breaker to the first line in the first position and to the second line in the second position; wherein the live and neutral switches are mechanically linked in the same position as each other.

16. A distribution box according to claim 14 or claim 15 comprising a cover which can be securely fastened over the switches.

17. A distribution box according to any one of claims 14 to 16 wherein substantially planar live and neutral bus bars are arranged in a multi-layered bus bar assembly as two of a stack of substantially planar bus bars pre-configured to make connections between the components.