GB2171846A - Mains electrical consumers' units - Google Patents

Abstract

A mains electrical consumers unit has a base part (10) which accommodates protection devices (24L) (circuit breakers or fuse links) and mains isolating switch (24M), and a cover which fits the base part (10) and is apertured to give access to the protection devices and the mains isolating switch. In order to facilitate wiring-in of the consumers' unit from any direction whilst minimising the size of the unit, a carrier (20) is provided on which the mains input isolation means (24M) is reversably mounted and switch further serves for mounting the protection devices (24L). A live feed rail (36) is provided offset towards a side of the base part (10) and can be uppermost or lowermost in normal use depending on the chosen orientation. The rail (36) serves for branching via the protection devices (24L) to individual local circuits from the mains input isolation means (24M). <IMAGE>

Description

SPECIFICATION Mains electrical consumers' units The invention relates to mains electrical consumer's units as conventionally used for distribution of mains electicity from the mains entry to premises, i.e. normally from the Supply Authority fuse and meter and to control various local circuits of a particular consumer, including lighting general power, and any special appliance or component circuits, such as cookers, shower heaters, cylinder immersion heaters, off-peak heating, etc.

Existing consumers' units are available from many sources and, as is to be expected, differ to some extent in design. Basically, they comprise a box containing bus bar and mounting systems for live earth and neutral, a mains switch or circuit breaker for isolating the live and neutral bus bars, and fuse-ways or circuit breakers branching from the live bus or rail and must afford space for wiring-in the consumers, circuits. That wiring-in involves distribution cable for which natural routes can be from any direction of the consumers' unit.

However, making consumers' units more compact, as seems to be a general trend for all equipment these days, results in offsetting at least the branched fuse ways or circuit breakers of the box so that the desirable amount of space for wiring-in consumers circuits will suit wiring-in from above or from below for a normal orientation of the consumers' unit and then with its mains isolating switch or circuit breaker either to the left or to the right on the box adjacent to an access provision for live rail associated fuses or circuit breakers of the local consumers' circuits. It is, of course, not always easy to feed consumers' circuits cables into the box adjacent to the space allowed for wiring them into the fuse-ways or circuit breaker holders, which is inconvenient to the installer.

It is an object of this invention to provide a consumers' unit less subject to such inconvenience.

According to this invention, then, there is provided and electrical consumers' unit comprising a box having a base part for electrical components including a live feed rail or conductor offset towards a side of the base part that can be uppermost or lowermost in normal use depending on the chosen orientation of the base part, the conductor serving for branching via protection devices to individual local circuits from mains input isolation means, and a cover part affixing to the base part and apertured to give access to the protection device and the mains input isolation means, the latter being reversibly mounted on a carrier associated with the base part that is preferably elongate and further serves for mounting the protection devices.

In preferred embodiments, a said elongate carrier on the one hand and bodies of the mains input isolation means and the protection devices on the other hand have cross sections that cooperate to the extent of retaining the bodies on the carrier after those bodies are slid onto the carrier from one end thereof, or clipped onto the carrier, and spacings of such bodies along the carrier are determined by engagement with teeth of a generally comb-like live rail or bus bar via electrical connection means of all of the bodies, or of at least the bodies of the protection devices and then with a further ccnducting link to the body of the mains input isolating means.

Reversibility is assured if the body of the mains isolation means has similar inputs at each end considered transversely of the carrier for taking a said tooth or further link and local circuit wiring with equal facility, and the cooperating cross-sections are symmetrical, so that the body can be fitted in either orientation of its said ends. Similar considerations apply to the bodies of the protection devices if same have a normal orientation as applies to circuit breakers rather than fuse-ways.

It will be appreciated that such reversibility allows the base part of the box to be fixed at alternative 1800 orientations, i.e. with the live rail or conductor or bus bar at top or bottom and the wiring-in space oppositely extending from bottom or top of the box.

Moreover, the slide-on or clip-on mounting of the aforesaid bodies on the carrier can permit another aspect of flexibility by way of the mains isolation means being at either end thereof, i.e. with the live conductor or bus bar extending to left or to right thereof. That is certainly so for a double pole mains isolation means intended to switch both poles simultaneously as, then, it is immaterial which of its two input terminals takes the live connection so it can always be the one closest to the protection devices, though it may well then be necessary for the neutral rail or bus bar, and perhaps the aforesaid live link, physically to have alternative hands of connection, say providing both with one to be snipped off.

A preferred neutral bus bar is elongate with a row of apertures and cooperating clamp screws and integral L-shaped side extension(s) by which it is connected into the mains isolation means and then presents the neutral rail or bus bar beyond the mains isolation means and at right angies to the carrier.

A preferred earth termination rail or bus bar is also elongate with multiple apertures and cooperating clamp screws, and is conveniently connected directly to the base part in a corner, most conventional at least in two sideadjacent related carriers.

Such electrical provisions with a consumers' unit hereof enable complete flexibility of assembly for top or bottom location of the live rail or bus bar and left or right position of the mains isolation means. It is even possible to have separated sets of protection devices for different tariffs of supply within the same consumers' unit.

So far as said access provision is concerned, a cover part with a single aperture is envisaged serving all of the protection devices and the mains isolation means.

Specific implementation of this invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic plan view of the base part of a consumers unit box with some parts dashed; Figure 2 is a diagrammatic sectional view of a carrier and switch body; and Figure 3 is a diagrammatic plan view of a cover part.

In the drawings, a consumers' unit comprises a generally rectangular base part 10 in the form of a hollow open-fronted box or tray with a base lOB, and an associated cover part 12 also of generally rectangular open box or tray-like form to fit to the base part in forming an overall box of the consumers' unit.

Fitting together is shown by way of screws through holes 14 in the cover part into hollow posts 16 on the base part, but other means may be used instead of screws.

Secured to the base part offset to one side of its main axis 18 is an elongate carrier 20 shown as being of iipped channel section for securement by its base web 20B, to the base 10B of the base part 10. Upstanding angled sides 20S and/or lips 20L, actually both as shown, can cooperate with appropriately formed grooves 22 with undercut sides 22S of bodies 24. Springs, normally of leaf type but shown diagrammatically at 26, usefully serve to aid rattle-free positive location of the bodies 24 on the carrier 20.

As shown, the bodies 24 are intended to represent either of local circuit breakers (24L) or mains isolating switch (24M), see switch dolly 24D in Figure 2. It is convenient to consider a mains isolating switch 24M of conventional double pole type as equivalent to two conjoined bodies each similar to a local circuit breaker body 24L, and even more convenient for that to be physically the case despite the heavier duty requirement of the mains isolating switch 24M, as is, indeed, readily achieved in practice, see dashed lines 28 in Figure 1. Accordingly, similar end connection provisions (30) via entries 30E and clamp screw accommodations 30C are shown in Figure 2.

Such bodies 24M and 24L are shown mounted side-by-side in a row on the carrier 20 in Figure 1 and with their ends providing connection provisions conveniently extending beyond sides of the carrier 20, though that is a matter of design preference only. As so installed, there are relatively narrow and wide spaces between those connection ends of the bodies 24 and opposite long sides 32A, 32B of the base part 10, respectively. The narrow space (34N) is used for connection to a live conductor/rail or bus bar 36 and the wide space (34W) is available additionally to the aforesaid narrow space for running in wire from local circuits, see also dashed circular "knock-outs" in the base 10B.

The live conductor or bus bar 36 is shown as being of comb-like formation with regularly spaced teeth 36T corresponding to desired relative location of the bodies 24 and entrant clamping electrical connection provisions 30 at one set of ends of the bodies 24. Corresponding provisions (30) at the other set of ends of the bodies 24 will, of course, be used for making connection to live wires of local circuit cables. It will be appreciated that the teeth 361 may be cranked or joggled, say to aid fitting of and match the desired slope of a cover 38 for at least the live bus bar 36, preferably also the clamp screws of cooperating accommodations 30C therefor.

It will further be appreciated that the live bus bar or rail 36 could be one tooth shorter and a separate link provided for making connections between the mains isolating switch 24M and the first adjacent local circuit body 24L or the end of the live bus bar or rail itself, and may be required if the end connection provisions of body 24M differ from those of bodies 24L. If, as we prefer, there is to be the option of fitting the mains isolating switch 24M to either end of the carrier 20, alternative different handed versions of such separate link may be required. Another alternative would be to extend the live bus bar or rail at each end in an appropriate integral extra tooth formation and cut off the one not used.

As shown in Figure 1, the end-most one of the end connection provisions (30) of the mains isolating switch body 24M at its end for the narrow space 34N carries and makes electrical connection with a neutral bus bar or rail 40 via a returned and usually cranked end extension 40E thereof. The neutral bus bar or rail 40 is shown as of an otherwise generally conventional form affording multiple accommodation 40A for clamp screws. It is, however, advantageous in obtaining a compact assembly of the parts 20, 24, 36 and 40 for the extension 40E of the latter to be returned as shown, thereby enabling location of the neutral bus bar or rail 40 running generally at right angles to the carrier 20 live bus bar or rail 36 and the row of bodies 24. An alternative would be for the purpose of the integral extension 40E to be performed by a separate link of appropriate shape screw clamped at both ends.

It will further be readily appreciated that the aforementioned option of the body 24M being at either end of the carrier 20 can be achieved by providing alternative end extensions 40E, one to each side (see dashed in Figure 1), and to cut off the unused one, or to provide alter native different handed separate links, or a separate link with both options integral for one to be cut off.

An earth bus bar 42 is also shown, actually tucked compactly into a corner of the base part 1 0B at the wider space 34W, say secured by a screw through a central lug 40L into an appropriate boss on the base 10B or otherwise as may be desired. The corner chosen for Figure 1 is also that closest to the neutral bus bar 40, and the possibility of equivalent fixing at 44 in the other corner of the space 34W, say where the above mentioned option is exercised to put the mains body 24M at the other end of the corner 20. The possibility of fitting the earth bus bar or conductor 42 adjacent and parallel to the neutral bus bar or conductor 40 is also indicated at 44'.

It will be evident that the base part 10 could be equally readily installed in another orientation representing a 1800 rotation on the plane of the drawing, i.e. with the assembly 20, 24n 36 and 40 at the bottcm rather than the top as shown. Moreover, for bodies 24 with similar electrical connection provisions (30) at each end, they could be slid onto the carrier in an inverted attitude corresponding to said other orientation of the base part 10, i.e.

to give the normal or natural orientation of the switch dollies 24D. It will further be evident that such inversion would be required only of the mains body 24M if the bodies 24L were of fuse-ways which are not normally orienta tio n-reiated.

Turning to the cover part 12, it most conveniently has a single aperture 50 for access to central parts only of the bodies 24, i.e. not to its electrical connection ends, see raised part 24C with dolly 24D in Figure 2 to protrude through the aperture 50. As is conventional, the aperture 50 can be of a width requiring removal of actual fuse bodies from fuse-ways before the cover part 12 can be removed. In Figure 3, the aperture 50 is shown within a well represented by an inwardly-recessed lip 52 with adjacent space for identifying local circuits, also mains live and neutral for the above-mentioned option, typically on a segmented label 54. An actual cover is readily provided for snapping in the well of lip 52, or otherwise fitting over the aperture 50 and/or the well, for example hinged at the top or bottom well sides of Figure 3.It is even quite feasible for the mains switch, or the local circuit breakers/fuses, to be separately, at least additionally, covered by another or subsidiary actual cover.

A particular styling is indicated in Figure 3 for the cover part 12, specifically stepping thereof at 26 to a shallower overall box depth at 58, which it will be appreciated can be uppermost or lowermost for the alternative orientations for base part installation.

The capability to have wiring-in space at top or bottom of a normal orientation of the described consumers unit is very useful, as, we believe, is the ability to have the mains isolating switch to either left or right in either orientation. Additionally, it will be appreciated that shorter or shortened live bus bars or rails would allow two or more to be used in the same consumers' unit and relative to separate mains isolation switches (any of which can then be medially disposed as the carrier 20), and thereby cope with multiple tariff supplies out of the same unit.

Claims (16)

1. A mains electrical consumers' unit comprising a box having a base part for electrical components including a live feed rail or conductor offset towards a side of the base part that can be uppermost or lowermost in normal use depending on the chosen orientation of the base part, the conductor serving for branching via protection devices to individual local circuits from mains input isolation means, and a cover part affixing to the base part and apertured to give access to the protection device and the mains input isolation means, the latter being reversibly mounted on a carrier associated with the base part that further serves for mounting the protection devices.
2. 2. A mains electrical consumers' unit as claimed in claim 1 in which the carrier is elongate.
3. 3. A consumers' unit as claimed in claim 1 or 2 in which said carrier on the one hand and bodies of the mains input isolation means and the protection devices on the other hand have cross sections that cooperate to the extent of retaining the bodies on the carrier.
4. 4. A consumers' unit as claimed in claim 3 in which the bodies are a sliding fit onto the carrier from one end thereof, or are a clip fit onto the carrier.
5. 5. A consumers' unit as claimed in claim 3 or 4 in which the spacings of at least the bodies of the protection devices along the carrier are determined by engagement with teeth of a generally comb-like live rail or bus bar via electrical connection means of said bodies.
6. 6. A consumers' unit as claimed in claim 3 in which the spacing of the mains input isolation means relative to the protection devices is determined by engagement with a tooth of said comb-like live rail via electrical connection means of said mains input isolation means.
7. 7. A consumers' unit as claimed in claim 5 comprising a further conducting link to the body of the mains input isolating means.
8. 8. A consumers' unit as claimed in claim 6 or 7 in which the body of the mains isolation means has similar inputs at each end considered transversely of the carrier for taking a said tooth or further link and local circuit wiring with equal facility, and the cooperating cross-sections are symmetrical, so that the body can be fitted in either orientation of its said ends.
9. 9. A consumers' unit as claimed in claim 6 or 7 in which the bodies of the protection devices have similar inputs at each end for talking a tooth and local wiring with equal facility, and the cooperating cross-sections are symmetrical, so that the bodies can be fitted in either orientation of their said ends.
10. 10. A consumers' unit as claimed in claim 4 wherein the slide-on or clip-on mounting of the aforesaid bodies on the carrier permit another aspect of flexibility by way of the mains isolation means being at either end thereof.
11. 11. A consumers' unit as claimed in any preceding claim further comprising a neutral bus bar which is elongate with a row of apertures and cooperating clamp screws and inte gral L-shaped side extensign(s) by which it is connected into the mains isolation means and then presents the neutral bus bar beyond the mains isolation means and at right angles to the carrier.
12. 12. A consumers' unit as claimed in any preceding claim having separated sets of protection devices and/or mains input isolation means for different tariffs of supply within the same consumers, unit.
13. 13. A consumers' unit as claimed in any preceding claim in which the cover part has a single aperture serving all of the protection devices and the mains isolation means.
14. 14. A consumers' unit as claimed in claim 13 in which the aperture is of a width which requires removal of fuse bodies from fuse way protection devices before the cover part can be removed.
15. 15. A consumer unit as claimed in claim 3 or any one of claims 4 to 14 when appendent to claim 3 in which the carrier is a lipped channel section for securing by its base web to the base part, and upstanding angled sides and/or lips for cooperating with appropriately formed grooves with undercut sides of the bodies.
16. 16. A consumers' unit constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.