GB2461885A - Electrical distribution box with window in cover - Google Patents

Abstract

An electrical distribution box, for connecting a mains electrical supply to a plurality of separate circuits through circuit breakers 7 which project through holes 6 in the cover 2 of the box so that they are switchable when the cover is in place, includes a window 11 in the cover to allow an information display panel 9 within the box to be visible when the box is closed. The information display shows circuit identification information, identifying which circuit is associated with which circuit breaker. The window allows direct access to the information put in place when the box was first configured, obviating risk of transcription errors when such information is transferred to a separate external information display panel on the outside of a distribution box. The window may also be used to assist with cover alignment when closing the cover, and may include a seal (17, Fig 3). The window may be an opening 11, or a glazed (eg plastic) window (16, Fig 3).

Description

Electrical Distribution Box with Cover The invention relates to an enclosure for holding electrical circuit distribution, which is typically mounted on internal walls of buildings. In particular it relates to an electrical switchgear enclosure, also known as a consumer unit or an electrical distribution box, which provides a centre for the distribution of mains electrical power supply to a plurality of different circuits through individual circuit breakers for each supplied circuit. In particular, the invention relates to electrical distribution boxes with covers for preventing accidental ingress to the inside space of the distribution box in order to prevent risk of electrocution of humans.

Electrical distribution boxes are placed in buildings in order to allow the electrical mains power supply to be distributed to a plurality of circuits. For instance, in a dwelling house, there may be separate circuits for the upstairs lighting, downstairs lighting, upstairs power sockets, downstairs power sockets, oven, alarm system, external wall sockets, etc. The convenience of such a distribution box is that each separate circuit powered from box may be provided with an individual circuit breaker. The type of circuit breaker may be one which switches to open circuit when an excessive current is drawn on the individual circuit (e.g. for a lighting circuit) or may be a circuit breaker adapted to also switch to open circuit when there is a leakage of current to earth (e.g. for use with external sockets used for gardening tools). The purpose of the circuit breakers is to prevent risk of fire or electrocution when there is a fault in an apparatus connected to the specific circuit. The advantage of the distribution box is that a fault on one circuit can be dealt with separately, without loss of power to all the other circuits fed through the electrical distribution box. Instead of circuit breakers, it was common to use fusible wires but these are now largely obsolete.

Unlike old-style fuse wires, circuit breakers may trip to the open circuit state as a result of minor perturbations to the current in a circuit. It is undesirable for non-specialist users to have access to the internal space of the electrical distribution box because of the presence of high current mains cables. Hence, in order to avoid the need to call out a qualified electrician to switch a circuit breaker every time a circuit breaker switches (e.g. when a light bulb fuses), it is now conventional for the circuit breakers to be switchable through holes in a cover of the electrical distribution box. The cover prevents the user from accidentally contacting the circuitry within the box. Typically the circuit breakers project out from the inside of the electrical distribution box through apertures provided in the cover of the box, the apertures being adapted to snugly fit around the projecting circuit breakers so that no accidental access can be gained into the box between the apertures and the circuit breakers.

An adequate seal around the circuit breakers is required, commensurate with various standards, in order to prevent the ingress of parts of the human body, wires, screws, building debris, rubble, plaster or dust. International standard IEC 60529 classifies the level of protection provided against the intrusion of such solid objects. Typically, electrical distribution boxes require an ingress protection rating of IP4X, which means that the ingress of objects greater than 1mm in size is prevented.

Another advantage of the separate circuit breakers for different circuits within a building is that the circuit breaker can be deliberately switched off when it is necessary for maintenance or repair work to be carried out on a particular circuit. This means, for instance, that the lighting circuit can be isolated from the mains whilst a replacement light fitting is being fitted without the need to isolate the rest of the circuits supplied by the electrical distribution box from mains power. In order for this to be achieved safely and reliably, it is necessary to identify clearly which circuit breaker is associated with which specific circuit. The circuit breaker switches themselves are too small to allow them to be marked with information identifying the circuit, and also the circuit breakers may have to be replaced, leading to loss of information. Hence it is conventional to provide a display panel on the cover of the distribution box, typically situated adjacent to the projecting, circuit-breaker switches, identifying which circuit corresponds to which circuit breaker. Typically this will be written as "upstairs lights", upstairs sockets", "oven", etc. in a domestic situation, but circuit identifiers may be more appropriate in a commercial or industrial setting: such as "Al ", "A2", "321 C", etc. -where the codes used are identifiable to specific circuits by a user of the system.

Typically, the circuit identification information is written onto an indicator panel contained within the electrical distribution box. This indicator panel is typically part of a holder within the electrical distribution box, with the holder adapted to hold the circuit breakers in place. In the prior art, the indicator panel is only accessible when the cover of the electrical distribution box is in an open configuration, allowing access to the high current mains supply. In order for the circuit identification information to be visible when the cover is in a closed configuration, preventing accidental access to the interior space of the electrical distribution box, it is conventional for the electrician initially configuring the electrical distribution box to transcribe the circuit identification information from the indicator panel hidden inside the box to the display panel visible on the outside of the cover of the box, prior to locking the cover into its closed configuration, in which the indicator panel is no longer visible to a user.

It has now been realised that there is a potential problem with such transcription, in that there is a possibility for errors to be made when transcribing the circuit identification information from the internal indicator panel to the external display panel. This could potentially cause accidents, if a user believes that a circuit has been isolated from the mains supply when it is still live.

Hence it is an object of the present invention, amongst others, to provide an electrical distribution box where the risk of errors in the circuit display information is reduced compared to the prior art. Preferably, this should be achieved without significant increase in risk of accidental access of humans to the mains supply within the electrical distribution box.

In a first aspect, the invention provides an electrical distribution box having an internal space containing a holder adapted to hold a plurality of circuit breakers connecting a mains electrical power supply to a plurality of circuits, the electrical distribution box comprising a cover adapted to prevent accidental ingress to the internal space by a human when the cover is in a closed configuration, attached to the box, wherein the circuit breakers are switchable through holes in the cover when in the closed configuration, the holder comprising an indicator panel adapted to display circuit identifier information identifying each circuit supplied by each circuit breaker, characterized in that the cover comprises a window adapted to allow the circuit identifier information on the indicator panel to be visible when the cover is in the closed configuration.

Typically, the holder will be provided with a plurality of busbars each connected to a part of the mains supply (live, neutral, earth) with the circuit breakers being held by the holder and appropriately connected to each of the busbars in order to supply a plurality of separate circuits from the electrical distribution box.

The mains supply will enter the internal space of the box, to connect with the circuit breakers, and the power cables for the individual circuits will leave the internal space of the box through appropriate ports, the ports being adapted to prevent accidental human ingress to the internal space of the electrical distribution box.

The cover is moveable from a closed configuration, where it prevents accidental human access to the internal space of the electrical distribution box, to an open configuration allowing access to the internal space of the electrical distribution box when the box is, for instance, to be initially configured, maintained or repaired (usually by a qualified professional tradesman). The cover may be a removable cover in the form of a lid which may be completely removed from the rest of the distribution box, but preferably, the cover is in the form of a lid attached at an edge to the electrical distribution box by a hinge, and moveable from an open to a closed configuration, and vice versa, by pivoting around the hinge. One or more fastening means, such as a screw fastener, may hold the lid in the closed configuration, but preferably the fastening means includes a locking means whereby access of unauthorised persons is prevented. For instance, a key-operated lock or a combination lock may be used to lock the cover in a closed configuration.

Suitably, the window is an opening in the cover and the indicator panel is positioned to prevent accidental contact between the internal space and a human through the opening when the cover is in the closed configuration.

Preferably, a seal is provided between the indicator panel and the opening, so that accidental ingress of human body parts, dust, water, etc. is further inhibited.

Preferably, the indicator panel comprises a plinth holding the indicator panel and adapted to project through the opening whereby the opening is closed by plinth the when the cover is in the closed configuration. Any seal may then be provided between the edges of the plinth and the edges of the opening.

Preferably, the indicator panel is of a minimum size required to adequately display the circuit identification information. The window is suitably adapted to match the size of the indicator panel such that the window is no larger than required to allow the indicator panel to be visible through the window. This gives the advantage that the window interferes only minimally with the structural integrity of the cover.

When the window is in the form of an opening through which the indicator panel is visible, a further advantage is that changes to the circuit display information may be made without the need to gain access to the potentially dangerous internal space of the electrical distribution box. For instance, in a commercial setting, if a room is renumbered, this renumbering can be copied onto the indicator panel as new circuit identifier information.

When the indicator panel comprises a plinth, this may suitably be adapted to facilitate the alignment of the cover with the electrical distribution box when as the cover is moved from an open configuration, allowing human access to the internal space, to the closed configuration in which accidental access is prevented. Although the holes through which the circuit breakers project should assist with such alignment, the standard shape of the circuit breakers means that they are not adapted to facilitate alignment. The plinth does not have to meet any such standard shape, and so may be adapted, for instance by having tapered edges, to assist with the alignment of the cover as it mates with the opening in the cover in the closed configuration.

In a further embodiment of the first aspect of the invention, rather than being an opening, the window may be a glazed window positioned to allow the circuit identifier information on the indicator panel to be visible when the cover is in the closed configuration. The glazing of the window may be of glass, but is preferably a shatterproof material such as shatterproof glass or a clear polymeric material, e.g. polyacrylate. Preferably, the window is of a size adapted to substantially match the size of the indicator panel, whereby the window is of a minimal size allowing the indicator panel to be visible when the cover is in the closed configuration. For instance, the glazed window may be configured to provide a viewing area adapted to match a display surface of the indicator panel. This gives the advantage that only part of the cover needs to be of potentially costly clear material, and less expensive material such as sheet metal may be used for the rest of the cover.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a perspective view of a first embodiment of the invention where the window is an aperture in the cover, the cover being in the closed configuration, Figure 2 shows the first embodiment with the cover in an open configuration, Figure 3 shows a second embodiment of the invention where the window is a glazed window.

Turning to the first embodiment as shown in Figures 1 and 2, an electrical distribution box body 1, has a cover 2, which is attached at one edge to the rest of the electrical distribution box body 1 by hinges 3. A lockable fastener 4 is mounted on the cover 2 such that it can engage with a plate 5 on the electrical distribution box body 1.

The cover 2 has two holes 6 through which the circuit breaker arrays 7 project when the cover 2 is in the closed configuration shown in Figure 1.

A holder 8 including a plinth 12 with an indicator panel 9 is held within the inner space of the electrical distribution box body 1. The holder 8 holds the circuit breaker arrays 7 and provides electrical connections (not shown in detail) between the electrical mains supply 13 and the circuit breakers 7.

Cables passing out of the electrical distribution box body at the port 10 supply the individual circuits associated with each circuit breaker 7.

An opening 11 in the cover 2 is adapted to fit snugly around the shape of the plinth 12 of the holder 8 when the cover 2 is in the closed configuration as shown in figure 1.

In use, when the distribution box is first configured, with the cover 2 in the open configuration, the mains supply 15 is connected to the various circuit breakers 7. Information identifying the circuit associated with each circuit breaker 7 is applied to the indicator panel 9, typically by writing on it. In the Figures, the circuit identifier information 14 is shown as letters, but could, for instance, be a circuit name such as "room 12A" or "kitchen sockets". At this stage, the cover 2 is closed and locked in place by engaging the lockable fastener 4 with the plate 5 using a key (not shown). As the cover 2 is closed, the circuit breakers 7 project through the holes 6, closing them off with regards entry to the internal space of the distribution box whilst allowing access to the switches 15. The plinth 12 on the holder 8 projects through the opening 11 and closes the opening with regard to accidental human access to the internal space of the distribution box. The indicator panel 9 on the surface of plinth 12 is clearly visible from outside the distribution box.

Turning to Figure 3, this shows a second embodiment of the invention where the window in the cover 2 is a glazed window 16 of shatterproof glass held in the cover 2 by a seal 17. In this embodiment, the plinth 12 of the holder 8 is positioned so that it sits adjacent to and behind the window 16 when the cover 2 is in the closed configuration. All other features of this embodiment are as for the first embodiment.

In use, when the distribution box is first configured, with the cover 2 in the open configuration, the mains supply 15 is connected to the various circuit breakers 7. Information identifying the circuit associated with each circuit breaker 7 is applied to the indicator panel 9, typically by writing on it. The cover 2 is then closed and locked in place by engaging the lockable fastener 4 with the plate 5 using a key (not shown). As the cover 2 is closed, the circuit breakers 7 project through the holes 6, closing them off with regards entry to the internal space of the distribution box whilst allowing access to the switches 15. The plinth 12 on the holder 8 sits just behind the glazed window 16. The indicator panel 9 on the surface of plinth 12 is clearly visible from outside the distribution box through the clear glazed window 16, and the window 16 also prevents accidental human access to the inner space of the distribution box.

It will be appreciated that numerous modifications to the above described embodiment may be made without departing from the scope of the invention as defined in the appended claims. For example, the cover 2, rather than being hinged to the distribution box body 1 may be entirely removable. For instance, the plinth 12 may have a rubber seal around its perimeter in order to give a better closure between the plinth 12 and the opening 12 in the cover 2 when the cover 2 is in the closed configuration.

The described and illustrated embodiments are to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the scope of the inventions as defined in the claims are desired to be protected. It should be understood that while the use of words such as "preferable", "preferably", "preferred" or "more preferred" in the description suggest that a feature so described may be desirable, it may nevertheless not be necessary and embodiments lacking such a feature may be contemplated as within the scope of the invention as defined in the appended claims. In relation to the claims, it is intended that when words such as "a," "an," "at least one," or at least one portion" are used to preface a feature there is no intention to limit the claim to only one such feature unless specifically stated to the contrary in the claim. When the language "at least a portion" and/or "a portion" is used the item can include a portion and/or the entire item unless specifically stated to the contrary.

Claims (7)

1. Claims 1. An electrical distribution box having an internal space containing a holder adapted to hold a plurality of circuit breakers connecting a mains electrical power supply to a plurality of circuits, the electrical distribution box comprising a cover adapted to prevent accidental ingress to the internal space by a human when the cover is in a closed configuration, attached to the box, wherein the circuit breakers are switchable through holes in the cover, the holder comprising an indicator panel adapted to display circuit identifier information identifying each circuit supplied by each circuit breaker, characterized in that the cover comprises a window adapted to allow the circuit identifier information on the indicator panel to be visible when the cover is in the closed configuration.
2. 2. An electrical distribution box according to claim 1 wherein the window is an opening in the cover and wherein the indicator panel is positioned to prevent accidental contact between the internal space and a human through the opening when the cover is in the closed configuration.
3. 3. An electrical distribution box according to claim 1 or claim 2 wherein a seal is provided between the indicator panel and the opening.
4. 4. An electrical distribution box according to any one of the preceding claims wherein the indicator panel comprises a plinth holding the indicator panel adapted to project through the opening whereby the opening is closed by plinth the when the cover is in the closed configuration.
5. 5. An electrical distribution box according to claim I wherein the window is a glazed window positioned to allow the circuit identifier information on the indicator panel to be visible when the cover is in the closed configuration.
6. 6. An electrical distribution box according to claim 5 wherein the window is of a size adapted to substantially match the size of the indicator panel, whereby the window is of a minimal size allowing the indicator panel to be visible when the cover is in the closed configuration.
7. 7. An electrical distribution box substantially as hereinbefore described with reference to and as shown in the accompanying figures.