Field of the Invention

The present invention relates to fuseboards and distribution boards, in particular to fuseboards for use in single or three phase installations in buildings, including: domestic, commercial and industrial premises.

Background

Fuseboards intended for use in buildings typically have inputs of either single or three phase power, at AC voltages of less than 1000V, more typically 400V for three phase and 240V for single phase in the UK, and other voltages in other countries, for example 1 15V in the USA. Typically a fuseboard is adapted for one of single or three phase power input. Typically fuseboards have main isolator switches controlling the input from the power supply, and a number of subsidiary isolator switches controlling output circuits branching from the outputs of the main isolator switches.

Typically the main isolator switches comprise RCD (residual current devices) current trips to isolate the input in the event of a circuit failure such as a short circuit. In some older fuseboards the output circuits are protected by fuses. In all modern fuseboards, all output circuits are protected by an RCD. However, in some applications an RCD device is not advantageous: for example in control of essential circuits such as an alarm power supply, an RCD device is not required as accidental trip of the RCD could lead to a hazardous condition. Prior art fuseboards have the disadvantage that they cannot accommodate such circuits as well as RCD-protected circuits. They also have the disadvantage of requiring either an expensive three-phase RCD device or an expensive multiplicity of RC devices, one for each output circuit.

Summary of the Invention

Embodiments of the present invention provide a (usually relatively cheap) single phase RCD device for each incoming phase, the outputs from these three devices can then be used recombined to provide one or more RCD-protected three-phase outputs and/or can be used singly each to provide one or more RCD-protected single phase outputs. Also, when there is required one or more non-RCD-protected outputs, the same can be taken off prior to the RCD devices, singly for single phase and in combination for three-phase.

One aspect of the invention is a fuseboard as claimed in claim 1.

Embodiments may provide any one or more of the following features:

• in which the input means comprise an input isolator having said at least three outputs; • in which each of said first output circuits comprises a circuit breaker;

• in which each of said first output circuits comprises an overload protection device;

• in which said input means comprises a multi-pole isolator having said at least three outputs, these being respective single-phase line outputs of respective poles of the isolator;

• in which three poles, each after protection by a said single-phase RCD, are available to be used in combination to provide a three-phase said first output circuit from the fuseboard;

• in which said RCD means output comprises connected from each said single-phase RCD at least one busbar and one or more said first output circuits;

• which has at least one second output circuit connected to the input side of a said RCD so as not to be RCD-protected;

• in which three poles, each before protection by a respective said single-phase RCD, are available to be used in combination to provide a three-phase said second output circuit from the fuseboard.

Embodiments provide an improved fuseboard that may provide both RCD protected and non-RCD protected circuits in a flexible manner, in some embodiments together with the capability of accepting both single and three-phase power supplies in a common device, being able to accommodate large number of circuits (18 or more) and being able to handle large loads.

Embodiments provide a fuseboard that comprises three single-phase RCD's and is adapted to provide a plurality of single phase and/or three-phase outputs from each of these and/or from them used in multi-phase combination, and in one embodiment provides both RCD-protected and non-RCD-protected circuits.

Such a device addresses a gap in the present provision of such devices market need and would have considerable practical and commercial value.

Embodiments provide a fuseboard comprising: a power input having at least one line and one neutral input; an input isolator in line with each line input; an input RCD means in electrical connection to the output of each input isolator; a line busbar in electrical connection to the output of each input RCD means and a neutral busbar in electrical connection to the neutral input; one or more first output circuits, each comprising an output circuit breaker means in electrical connection to at least one line busbar and an output connector in electrical connection to the output of the output circuit breaker means.

Preferably each first output circuit further comprises a connection to the neutral busbar.

Even more preferably the output connector is in the form of a terminal block as known in the art, comprising at least a first terminal connection in electrical connection with the output of the output circuit breaker means and a second terminal connection in electrical connection with the neutral input. In some embodiments the output circuit breaker means may comprise a double pole switch means that acts in use to break both the line and neutral connections to the relevant busbars.

In some particularly preferred embodiments the output circuit breaker means may comprise an over-current trip means. In some embodiments the output circuit breaker means may comprise an RCD device, or an RCBO (Residual Current circuit Breaker with Over-Current protection) device.

In a preferred embodiment the fuseboard is adapted for a three-phase power input and comprises three line inputs and one neutral input, an input isolator pole in line with each of the three line inputs, three input RCD means, three line busbars, one in electrical connection to the output of each RCD means, and at least one first output circuit in electrical connection to one line busbar.

Advantageously the fuseboard comprises a plurality of first output circuits, some connected to a first line busbar, others connected to second and third line busbars.

In a preferred embodiment the three input RCD means comprise separately actuable independent RCD means, one in line with each line input. In this way each phase is protected by a separate RCD device.

In another preferred embodiment the fuseboard further comprises one or more second output circuits, each comprising a second output circuit breaker means in electrical connection to the output of an input isolator and a second output connector in electrical connection to the output of the second output circuit breaker means.

Preferably the second output connector comprises a line connection in electrical connection to an output from an input isolator and a neutral connection in electrical connection with the neutral input.

Preferably the second output circuits further comprise switch means in series with the line and neutral connections, and in preferred embodiments additionally overcurrent trip or fuse means in series. In use such switch means serve to isolate each second output circuit individually from the outputs of the input isolators. In preferred embodiments the fuseboard of the invention is housed in a cabinet having a long and a short axis and a depth. In some embodiments the cabinet is formed from an insulating material. In other embodiments the cabinet may be formed at least in part from metal, the metal components preferably being connected to electrical earth.

In a preferred embodiment the components of the fuseboard are laid out within the cabinet in a pattern that represents the sequence of power connections within the cabinet.

In a preferred embodiment the fuseboard components are laid out as follows, in sequence from a first end of the cabinet: input terminals for a three phase power input at a first end of the cabinet; then three isolators; then three input RCD devices positioned further from the first end than the isolators; then the output circuit breakers positioned closer to the second end of the cabinet.

In embodiments comprising both first output circuits that are RCD-protected and second output circuits that are not RCD-protected a preferred layout is as follows in sequence from a first end of the cabinet: input terminals for a three phase power input at a first end of the cabinet; then three isolators; then the second output circuit breakers; then three input RCD devices; then the first output circuit breakers positioned closer to the second end of the cabinet.

In this way the first and second output breakers, and the location of the first and second output connectors within the cabinet, are clearly apparent to the user.

In preferred embodiments the fuseboard further comprises conductor means to connect the outputs from three input RCD devices arranged laterally to three busbars stacked one above the other suitable to feed into the rows of first output circuit breakers. In preferred embodiments having second output circuits, the fuseboard further comprises conductor means to connect the outputs from the input isolators arranged laterally to three busbars stacked one above the other suitable to feed into the rows of second output circuit breakers, and conductor means to connect the three busbars stacked one above the other from the second output circuit breakers to the inputs of the three input RCD devices arranged laterally.

Preferably the fuseboard further comprises an earth busbar. In preferred embodiments the neutral busbar and the earth busbar are located at opposite sides of the cabinet.

In preferred embodiments the fuseboard of the invention is adapted to be used with either a three phase or a single phase power input without modification, in contrast with fuseboards of the prior art which are either for single or for three-phase supplies. In use, in some embodiments, a single phase installation may be changed to a three-phase installation without replacement of the fuseboard.

In preferred embodiments the isolators, RCD devices and internal metal conductor components are rated and dimensioned to handle a total number of output circuits above 18 and a total load exceeding 100 Amps.

Preferred embodiments of the invention will now be described, with reference to the Figures in which:

Brief Description of Figures

Figure 1 shows a front view of an embodiment of the invention

Figure 2 shows a side view of an embodiment of the invention

Figure 3 shows a three-quarter view of an embodiment of the invention

Figure 4 shows a second side view of an embodiment of the invention

Figure 5 shows a rear view of an embodiment of the invention

Figure 6 shows an exploded view of an embodiment of the invention

Figure 7 shows a view of a first end of an embodiment of the invention

Figure 8 shows a view of a second end of an embodiment of the invention

Figure 9 shows a side exploded view of an embodiment of the invention

Figure 10 shows an exploded view of an embodiment of the invention

Figure 11 shows a three quarter view of an embodiment of the invention with a front cover closed

Figure 12 shows a sketch of a circuit diagram of an embodiment of the invention

Detailed Description of Figures

Figures 1 to 11 show a first embodiment of the invention having both RCD-protected and non-RCD protected circuits and being adapted for a three-phase input.

Figure 1 shows a front view of the front panel of the fuseboard showing a cabinet comprising from bottom to top: a three-pole input isolator; six second circuit breakers in electrical connection with the output of the input isolator; three RCD devices (or a three- pole RCD device in some embodiments) in electrical connection to the output of the input isolators; two banks of first output circuit breakers, 12 in each bank. The first output circuit breakers may be connected to line busbars from the three phase supply as appropriate. Preferably they are distributed among the phases. Preferably they are distributed in a recognised order among the phases and which phase each output circuit is connected to is indicated on the front panel.

Figure 3 shows a three-quarter view of the embodiment in figure 1 , additionally showing the input gland/aperture through which input power cables may pass. The logical layout of the fuseboard, indicating which circuits are protected by RCD - located above the RCDs - and which are not - located below, i.e. closer to the power input than the RCDs, is a feature of preferred embodiments of the invention.

Figure 2 and figure 4 show side views and figure 5 a rear view of a cabinet of the embodiment shown in figures 1 and 3.

Figure 6 shows an exploded view of the components of the embodiment shown in the previous figures. Figure 9 and figure 10 show side and reverse angle exploded views of the same embodiment. In each of figures 6, 9 and 10 components are shown in levels from bottom to top, and listed from the first (input) end of the cabinet to the second, as follows:

Level 1 :

Back component of the cabinet, in preferred embodiments comprising a lightweight aluminium frame.

Level 2:

Second output circuit breakers, shown as having rail mounted circuit breaker format as known in the art

Three RCD breakers (or a 3-pole breaker), one for each line input

Two rows of first output circuit breakers, shown as having rail mounted circuit breaker format as known in the art

Level 3:

Earth (to the left) and neutral busbars - note in figure 6 the neutral busbar appears to lie between the two rows of the first output circuit breakers - preferably the neutral busbar lies along the right hand side of the cabinet, and its apparent position results from the nature of the exploded view. Locations are more clearly shown in figures 9 and 10. In preferred embodiments the neutral and earth busbars are located on opposite sides of the cabinet, for example with the neutral busbar located at the right hand side of the cabinet relative to inputs at the bottom.

Level 4: Input gland

Mounting brackets for circuit breakers and RCD devices

Glands for output cables.

Level 5:

Electrical bus connections transferring lateral to vertical orientation of conductors to fit the RCD and output circuit breaker connection configurations. In preferred embodiments these have configurations as shown in figures 6, 9 and 10, comprising three conductors separated by insulation layers, and forming three conducting pathways that lead from three metal conductors arranged in a lateral configuration to three metal conductors arranged in a vertically stacked configuration.

Level 6:

Three pole input isolator

Base or mounting components for the second and the first output circuit breakers Level 7:

Cabinet fascia. In use this is preferably covered by a front cover (not shown).

Figures 7 and 8 show the first and second ends of the cabinet of the embodiment, and figure 1 1 shows the embodiment with a front cover closed.

Figure 12 is a circuit diagram illustrating an embodiment of the invention which may also be part of the same embodiment of the fuseboard 28 as described above with reference to Figures 1 to 1 1. From bottom 54 to top 56 are shown: three input lines 24, marked L1 , L2 and L3; input isolator means 32, which comprises three input isolators 32; a neutral input 25, marked N, to a neutral busbar 91 ; a series of second output circuits 50, at least two (four being shown, by way of example) connected to each line 24 from the outputs

36 of the isolator means 32 (circuit breakers of the usual kind will be provided as respective second output circuit breakers, not shown, in each output circuit 50) and therefore incidentally also connected to the input side 35 of RCD's 34 (see next item) so as not to be protected by the RCD's 34; a respective single-phase RCD device 34 protecting each line 24 connected to the respective outputs 36; and first output circuits

37 connected to the outputs of the RCD devices 34, again shown (by way of example) as two (L2, L3) or three (L1) output circuits 37 being connected to each of the lines 24, with circuit breakers of the usual kind provided as respective first output circuit breakers (not shown). Neutral busbars 90 for each line 24 are indicated as N-L1 , N-L2 and N-L3. Earth busbars and connections of the usual kind are also provided (not shown). It will be observed from Figure 12 that, since the three line inputs 24, marked L1 , L2 and L3, may be respectively the three phases of a three-phase input, any group of L1 , L2 and L3 first output circuits 37 correspondingly then provides three phases, and can constitute a three-phase first output circuit 37 from three single-phase RCD's 34. Similarly, any group of L1 , L2 and L3 second output circuits 50 correspondingly then provides three phases, and can constitute a three-phase RCD-unprotected second output circuit 50 from input isolator means 32.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention.

With respect to the above description then, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

It will be apparent to one skilled in the art, that features of the different embodiments disclosed herein may be omitted, selected, combined or exchanged and the invention is considered to extend to any new and inventive combination thus formed. Where a preference or particularisation is stated, there is implied the possibility of its negative, i.e. a case in which that preference or particularisation is absent.

Many variations of the invention and embodiments hereinbefore described will be apparent to people skilled in the art and all such variations are to be considered as falling within the scope of the invention.