GB2128820A

GB2128820A - Holding modular wiring devices on electrical wiring distribution systems

Info

Publication number: GB2128820A
Application number: GB08318202A
Authority: GB
Inventors: George Martenyi
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1982-10-19
Filing date: 1983-07-05
Publication date: 1984-05-02
Also published as: NZ205975A; GB2128820B; GB8318202D0; AU561438B2; AU8949982A

Abstract

In an electrical wiring distribution system including bus-bars (2) with rigid tapping terminals (12), modular wiring devices (one is shown) are arranged in rows and each device is held by an individual mount. A mount includes a guide tongue (10) and a holder (5) engaged with the wiring device and the tongue (10). The devices (1) and holder (5) are mounted on the tongue (10) and subsequent movement of the wiring device (1) causes engagement of a terminal (7) of the device with a rigid tapping terminal (2). <IMAGE>

Description

SPECIFICATION Electrical wiring distribution system The invention relates to an electrical wiring distribution system in which wiring devices, e.g. circuit protection switches, are held in lined-up arrangement and may be connected to a supply system which is, as a rule, a multiphase system, by a mounting foot of each respective wiring device being held on a holding means having a flat U profile with edges projecting laterally from its sides and the electrical terminals of the wiring devices each being connected to a respective connecting lead of the supply system.

Electrical wiring distribution systems branch an incoming supply system off into various load circuits which may be protected by circuit breakers. Auxiliary devices such as earth leakage circuit breakers or manually operated main switches which facilitate manual zero current switching of following branches independent of the circuit breaker, contact making clocks and other wiring devices may be accommodated in such distribution systems. Conventional wiring devices have a mounting foot which, as viewed from above, forms a recess which can be essentially regarded as a flat, inverted U. Projections or resilient noses may be arranged on the sides of the U to facilitate snap-action fitting of the wiring device onto a carrier rail in the form of a flat U with edges projecting laterally from its sides.Such wiring devices can be snap-fitted from above onto a carrier rail and lined up one alongside the other. A connecting lead of the supply system may be attached to one terminal and the load-side outgoing lead to another terminal. In such systems wiring devices may only be fitted or replaced as a rule by specialist personnel.

It has been deemed advantageous to construct wiring distribution systems in which wiring devices may be fitted and replaced in the live state, even by non-specialist personnel.

It is an object of the invention to provide an electrical wiring distribution system in which wiring devices may be replaced even in the live state without any danger to persons.

In the solution according to the invention the holding means has approximately the same width as a wiring device in the line-up direction of the wiring devices and recesses are formed on its sides, said recesses being capable of being slid with at least an aligned zone onto guide tongues formed on a carrier means of the supply system, whereby a rigid connection lead electrically insulated from the operating plane bears against a respective terminal of the wiring devices.

Electrical contact is obtained at the endow mounting motion during sliding on of a wiring device together with the holding means onto a guide tongue, whereby a terminal may be tightened through an access aperture with a suitable tool. It is of the essence that mounting of the wiring devices be effected through a simple slide-on action in which they are fixed through the electrical contact, but that the wiring devices have mechanically firm hold in a zone greater than that provided by support through the electrical connection.

In a solution known per se, L-shaped sides are provided on a carrier plate, the former having an inverted L profile, a flank of the mounting foot of a wiring device engaging behind the sides thereof.

Otherwise the wiring device is only held by the electrical connection, whereby a rigid connecting lead holds down the wiring device and fixes it in the mounting position. Connection rails are here preferably laid across the wiring devices, said connecting rails not being insulated from the operating plane during mounting (GB-PS 1 554614).

It is also known in the prior art that means for attachment of busbars may also be provided on a carrier plate for wiring devices (US-PS 3309 581). In this case the electrical contact is obtained at the bottom of the mounting base which, in association with mating contacts of the distribution system, provides electrical contact as also a clamp hold. In this case the wiring devices are only mechanically held in the zone of the electrical contact. A hooked-in corner of the wiring device outside the zone of electrical contact cannot provide a secure mechanical hoid.

In the wiring distribution system according to the invention it is of particular advantage, without mentioning the electrical insulation of the terminal of the wiring devices from the operating plane, that the wiring devices are disposed and held in a mechanically secure manner and are only fixed in the mounting position through the electrical connections without being subjected to considerable tensile forces, whereas if a wiring device has to be removed from the mounting position it is automatically isolated from the supply system.

In a simple construction, the carrier means is the base for a housing accomodating busbars, said housing projecting with integral collars over the electrical connection points of the wiring devices.

The embodiment of the housing accommodating the busbars may be in the manner of a duct closed by a, cover formed by the laterally projecting collars.

Duct and cover of the housing accommodating busbar are, for purposes of storage and mounting, preferably in the form of line-up sections each having a width equal to an integral multiple of device unit width.

A construction which is economical in manufacture and compact in its final state is obtained by the tongues being formed on both sides of a back in the manner of a comb and being attached at least to strip-shaped carriers with this back, strip-shaped carriers being spaced at least in the mounting zone for wiring devices by cranking and forming attachment means for the distribution system.

If the collars have guide penetrations for tools over the electrical connection points for the wiring devices, a wiring device can be connected to live busbars of the distribution system with conventional insulated tools, such as screwdrivers, without danger to personnel. On the one hand, the terminal of the wiring device is protected against random contact and on the other hand, the tool is prevented from slipping sideways onto other live parts.

The invention is to be described in greater detail with the use of an example of embodiment shown in rough schematic representation in the drawing in which: Figure 1 shows the essential part of the wiring distribution system in side view, whereby a wiring device is just being mounted on one side. For the sake of clarity a conventional distribution system housing in which the represented essential part may be disposed have been omitted.

Figure 2 shows a wiring device, in this embodiment a singie pole circuit breaker, in the nonoperative position with its mechanical and electrical connection parts for the wiring distribution system in an exploded view.

Figure 3 shows the wiring distribution system, corresponding to Figure 1, however without fixed wiring devices.

Figure 4 shows the essential part of the wiring distribution system, corresponding to Figure 3, in a sectional elevation.

The central part of an electrical wiring distribution system corresponding to Figure 1 may be imagined in a conventional housing of a wiring distribution system. It can hold wiring devices 1,e.g.circuit protection switches, in lined-up arrangement and facilitate connection to a supply system which is, as a rule, a multiphase system. The busbars with the three phases are arranged as supply bars 2 in a housing 3 which is preferably so constructed that it can stand up to forces acting on the busbars. The mounting foot 4 of the wiring device 1 is held on a holding means 5 with flat U profile and edges projecting laterally from its sides. For this purpose the wiring devices may be provided with projecting noses and/or resilient nubs in sides of the mounting foot 4.The electrical terminals 7 of the wiring devices 1 are, in the mounted state, connected to one respective connection lead 12 of the supply system, the busbars 2.

The holding means 5 has approximately the width of a wiring device in the line-up direction of the wiring devices 1. It has in its sides recesses 9 which are in alignment with each other and can be slid onto guide tongues 10, as may been seen from Figure 2.

Such guide tongues 10 are formed on a carrier means 11 of the distribution system. A rigid connection lead 12 presumed to be electrically insulated from the operating plane bears against and is clamped against one respective electrical terminal 7 of the wiring devices 1 when in the mounted state.

The carrier means 11, c.f. Figures 1,3 and 4 is the base of a housing 3 accommodating a busbar 2. The housing projects with integral collars 14 over the electrical connection points, in the present embodiment the terminals 7 of the wiring devices 1, and insulates them against the operating plane with manual operating element 15.

In the embodiment corresponding to Figures 3 and 4the housing 3 accommodating the busbars 2 is in the form of a duct closed by a cover 15. The cover also forms the laterally projecting collar 14.

The ducttrough 16 and cover 15 of the housing 3 accomodating the busbars 2 are, in the embodiment corresponding to Figures 3 and 4, capable of being lined-up and have a width equal to an integral multiple of a division unit. The term "division unit" is understood to mean the width of the narrowest wiring device when wider wiring devices have a width which is an integral multiple thereof.

The tongues lOin the embodiment are formed on both sides of a back in the manner of a comb, as may be best seen from Figure 3. The guide tongues 10 can be attached at least to strip-shaped carriers 18 which are cranked to provide spacing at least in the mounting zone for the wiring devices and form attachment means 19.

The collars 14 over the electrical connection points, the terminals 7 of the wiring devices, preferably have guide penetrations 20 for tools, corresponding to Figure 3.

The busbars 2 can be connected at projecting ends corresponding to Figure 3 to the supply system through terminals 21. Branches are run off from the busbars 2 within the housing 3, said branches each terminating in a respective connection lead 12 in such a manner that, in a three-phase system, the individual phases follow in sequence. A single-phase wiring device 1 in the form of a circuit protection switch 1 is then supplied with power through a rigid connection lead 12. The connection to the branch of the load system is then effected through an outgoing terminal 8 customarily arranged on the other narrow side, corresponding to Figures 1 and 2.

On the load side a flexible conductor can be connected to terminal 8 in the zero-current state, the wiring device 1 then being fitted onto a holding means 5 and being slid therewith onto one of the guide tongues 10 up to a limit position defined by the associated connection 12. The electrical connection point, that is the connection to connection lead 12, can be of resilient, self-supporting embodiment or realised through a conventional terminal 7. It is of decisive importance that the connection point is electrically insulated against the operating plane as also protected against accidental contact with neighbouring terminals through collars 14, whereby a suitable tool, in the case of terminal 7 a screwdriver, can engage through guide penetrations 20 without danger of slipping off onto other live parts. The guide penetrations may be sealed on compietion of mounting operations with plugs, if required in the colours characterising the respective phase conductors.

Replacement or dismounting is performed by first disconnecting the electrical connection, the terminal 7, whereon the installation device 1 may be withdrawn together with holding means 5 from the guide tongue. The load side, terminal 8 can then be disconnected in the zero current state. The holding means 5 can then be withdrawn. Wiring devices with snap-action holding can be released through a tilting motion when slightly slid off from the respective guide tongue, the holding means 5 subsequently being completely withdrawn from the guide tongue 10.

Afurther embodiment of the present invention will now be described with reference to the following additional drawings: Figure 5 is a view similar to Figure 2 of one further embodiment; Figure 6 is a longitudinal cross-sectional view through the holding means 5; Figure 7 is a view similar to Figure 2 of an additional further embodiment; and Figure 8 is a view similar to that of Figure 6 but of the arrangement of Figure 7.

It will be apparent that although the carrier means 11 is normally mounted upright in a vertical plane so that the holding means 5 are normally retained on the guide tongues 10 without difficulty, in some cases it may be desirable to mount the carrier means 11 extending in a horizontal direction.

Under these circumstances the holding means 5 positioned on those ones of the guide tongues 10 which are downwardly directed, would slide from the guide tongues 10. Thus it is desirable to provide an attachment means to retain the holding means 5 in position after it has been slid onto the corresponding guide tongue 10. This is also a desirable attribute when the carrier means is to be manipulated after the holding means 5 have been located on the guide tongues 10.

In accordance with one embodiment of the present invention the above described retaining means are realised by forming the holding means 5 with an arched base 30 as seen in Figure 5. As best seen in Figure 6, the arched base 30 and recesses 9 cooperate to form a frictional ciamp which retains the holding means 5 in position after the holding means 5 has been slid onto the guide tongue 10.

An alternative embodiment is illustrated in Figures 7 and 8. Here the retaining means takes the form of a protrusion 31 formed in the base of the holding means 5 and co-operable with an aperture 32 in the guide tongue 10. As seen in Figure 8 when the holding means is slid into its intended position, the protrusion 31 is located within the aperture 32 thus preventing the movement of the holding means 5 from the guide tongue 10 without the application of a substantial manual withdrawal force.

The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, may be made thereto without departing from the scope of the present invention.

Claims

1. An electrical wiring distribution system in which wiring devices are arranged and held in a row or rows for connection to a power supply system by a mounting foot of each wiring device being held by a corresponding holding means, said holding means having a substantially flat U-shaped profile with edges projecting laterally from the sides thereof, and the electrical terminals of the wiring devices each being connected to a respective connection lead of said supply system, in which the holding means has approximately the same width in the row direction as one wiring device, or an integral multiple of said width, and has recesses in its sides which permit the holding means to be slid onto a corresponding guide tongue formed on a carrier of said distribution system, whereby a rigid connection lead electrically insulated against the operating plane bears against a respective electrical terminal of the wiring device, and has retaining means to maintain the holding means in position after location on said correspond ing guide tongue.

2. An electrical wiring distribution system according to claim 1, in which the carrier means is the base of a housing accommodating busbars, said housing projecting with integral collars about the electrical terminals of the wiring devices.

3. An electrical wiring distribution system according to claim 2, in which the housing accom modating the busbars is formed in the manner of a duct closed by a cover which forms the laterally projecting collars.

4. An electrical wiring distribution system according to claim 3, in which the duct trough and cover of the housing accomodating the busbars is formed of sections having a width equal to an integral multiple of a division unit and is capable of being lined up.

5. An electrical wiring distribution system according to any one of claims 1 to 4, in which the guide tongues are formed in the manner of a comb on both sides of a back and are attached with said back at least to strip-shaped carriers which are cranked to provide spacing at least in the mounting zone for the wiring devices and form attachment means.

6. An electrical wiring distribution system according to claim 2, in which the collars about the electrical terminals of the wiring devices have clos able guide penetrations for tools.

7. An electrical wiring system as claimed in any one of the preceding claims, in which said retaining means comprises an arched base on said holding means, said arched base forming a frictional fit with said corresponding guide tongue when said holding means is slid into position.

8. An electrical wiring system as claimed in any one of claims 1 to 7, in which said retaining means comprises a protrustion on the base of said holding means engageable with an aperture in the corres ponding guide tongue when said holding means is slid into position.

9. An electrical wiring system as claimed in claim 1 and substantially as hereinbefore described with reference to, and as shown in any one of the embodiments illustrated in the accompanying draw ings.