GB2526404A - Residual current circuit breaker and assembly method - Google Patents

Abstract

A residual current circuit breaker 1 comprises an insulating-material housing 2 having front and fastening faces 4,5 connected by broad and narrow faces 7,6 and terminal receiving spaces (10, figure 2B) for receiving connection terminals (11, figure 2B). An electrical contact element 20, in a mounted state, is routed at least partially out of the housing 2 through an opening formed on the fastening face 5 and comprises a lug (21, figure 3A) designed to make contact with an externally arranged contact apparatus and a web (22, figure 3A) with a first end 22-1 connected to the lug, wherein the contact element 20 can be pivoted from a joining position to an end position in which its second end 22-2 is received in one of the terminal receiving spaces instead of a connection terminal. The contact 20 may comprise a securing element (24, figure 3A) that interlocks with a corresponding mating element on the fastening face 5. The lug may be designed in an L-shape having a first limb making electrical contact with a contact apparatus and a second limb for fixing the contact element 20 to the housing 2.

Description

Description

Residual current circuit breaker and assembly method The invention relates to a residual current circuit breaker which is in the form of a rail-mounted device and is intended to be used in an electrical installation distribution board.

The invention further relates to an assembly method for assembling a residual current circuit breaker.

In electrical installation technology, so-called differential or residual currents are detected using circuit breakers -for example residual current circuit breakers or differential current circuit breakers -which are suitable for this purpcse in order to protect persons against hazards which may arise when live parts of electrical installations are touched.

Differential currents may occur when a residual current flows to earth, for example via a faulty insulation or -in the event of contact -through the human body. In order to detect a differential current of this kind, the magnitude cf the current in a line leading to an electrical load, for example a phase line, is compared with the magnitude of the current in a line returning from the electrical load, for example a neutral conductor, with the aid of a so-called core-balance current transformer. In the residual current-free state, the sum of the electric currents flcwing to the load is equal tc the sum of the returning electric currents. If the currents are added vectorially, that is to say with respect to direction and with a sign, the signed sum of the electric currents in the feed and return lines is equal to zero in the residual current-free state. Conversely, in the event of a residual current which flows away to earth, the sum of the feeding and returning electric currents, which sum is detected in the core-balance current transformer, is not equal to zero. The current difference which is produced in the process leads to the circuit breaker being tripped and, as a result of this, to the correspondingly protected electrical circuit being disconnected. The term "residual current circuit breaker" can generally be used interchangeably with the terms Fl circuit breaker (Fl switch for short) , differential current circuit breaker (DI switch for short) or ROD (for Residual Current Protective Device) In order to be used in an electrical installation distribution board, low-voltage switching devices, which also include residual current circuit breakers amongst others, are designed as so-called rail-mounted devices. The designation "rail-mounted device" is given because a large number of rail-mounted devices of this kind are often arranged on a support element, the so-called supporting or top-hat rail, which is arranged in an electrical installation distribution board, in a row next to another in the electrical installation distribution board. The term "rail-mounted device" therefore designates a housing structure which is designed in such a way that the rail-mounted devices cart be fastened to the supporting or top-hat rail in a guick and convenient manner. To this end, the rail-mounted device has so-called fastening means on its fastening face, the said fastening means, by way of example, being in the form of snap-action hooks with the aid of which the rail-mounted device is latched to the supporting rail.

The so-called "pin-type devices" are rail-mounted devices in which one or more of the electrical connection terminals of the circuit breaker are replaced by so-called "pins". A pin of this kind is an electrical contact element which is routed out of the rail-mounted device at the fastening face. Since residual current circuit breakers are subjected to loading by rated currents of up to 125 A and momentary currents of up to 10 kA, the pins are usually designed as solid metal lugs with an appropriate thickness and appropriate level of conductivity. In the electrical installation distribution boards which are designed for pin-type devices of this kind, at least one of the electrical connections is accordingly no longer available as a connection cable which has to be clamped in a screw terminal of the circuit breaker, but rather a so-called busbar" is provided. This busbar is arranged directly on the rear wall of the electrical installation distribution board beneath the top-hat rail as standard. When the rail-mounted devices are snapped onto the supporting rail, the pins are inserted directly into the busbar in the process. This considerably simplifies assembly since the connection Lines of the individual devices no longer have to be screw-connected, this being time-consuming. The system is also extremely space-saving since corresponding distribution boards have to provide less installation space for copper cables.

However, special reguirements can be made of the design of the pin-type devices. Firstly, care should be taken that an adequate tight fit of the external pin is ensured. In this case, the problem arises, in particular, that the pin projects out of the housing on the fastening face of the rail-mounted device and therefore may be slightly bent or broken off, in particular during mounting of the device in the electrical installation distribution board, but also during transportation or other handling. This can be prevented by a correspondingly solid design and also a correspondingly configured tight fit of the pin on the housing.

Furthermore, when structurally configuring the pin-type devices, care should be taken that there is an adeguate electrical connection of the external pin to the conponents in the device: residual current circuit breakers are subjected to loading by rated currents of up to 125 A and momentary currents of up to 10 kA. It is therefore necessary to prevent excessive heating or even melting of the supply line to the pin by virtue of a correspondingly dimensioned current-carrying cross section under all circumstances.

Furthermore, problems also arise when mounting the pin-type devices since the external pin cannot be connected to the internal components by a simple plug connection when high current intensities occur. Therefore, a connection which is suitable for high currents, as can be produced by means of a cohesive joining method such as soldering or welding for example, is required. However, the creation of a soldered or welded connection of this kind in the circuit breaker is problematical since the joining method has to be designed with a correspondingly high level of performance given the required line cross sections, this requiring a high input of energy which may result in thermal damage to the housing.

Finally, the replacement of one of the electrical connection terminals by a pin leads to installation space problems, particularly in cases in which the pin is not arranged directly in the region of the connection terminal which is to be replaced: when electrical contact is made with the pin, care should be taken that the individual current-carrying components are adequately spaced apart from one another and/or insulated from one another within the residual current circuit breaker, particularly when the pin is arranged in the immediate vicinity of a connection terminal with a different polarity. Solutions which have been known to date provide for widening of the residual current circuit breaker in these cases -for example in the case of a two-pole circuit breaker to a housing width of three subdivision units -in order to ensure current is carried in a suitable and reliable manner. However, this is undesirable from the point of view of the customer on account of the increased space requirement in the electrical installation distribution board.

The object of the present invention is therefore to provide a residual current circuit breaker and also an assembly method for assembling the residual current circuit breaker, which residual current circuit breaker and assembly method at least partially eliminate the above-described disadvantages.

This object is achieved by the residual current circuit breaker and the assembly method according to the independent claims.

Advantageous refinements are the subject matter of the dependent ciaims.

The residual current circuit breaker according to the invention has an insulating-material housing with a front face, a fastening face which is situated opposite the front face, and also narrow and broad faces which connect the front and the fastening face. In this case, the insulating-material housing has, in the region of the narrow faces, a plurality of terminal-receiving spaces for receiving electrical connection terminals. The residual current circuit breaker also has an electrical contact element which, in the mounted state, is routed at least partially out of the insulating-material housing through an opening, which is formed on the fastening face, in the said insulating-material housing. In this case, the contact element has a lug which is designed to make electrical contact with an externally arranged contact apparatus. Furthermore, the electrical contact element has a web, the first end of said web being electrically conductively connected to the lug, and the second end of said web being designed to be electrically conductively connected to a primary conductor of the residual current circuit breaker. In this case, the contact element can be brought, i.e. moved, by virtue of a pivoting movement, from a joining position to an end position in which the second end is received in one of the terminal-receiving spaces instead of a connection terminal.

The end position therefore forms the end of the pivoting movement. On account of the structural configuration of the residual current circuit breaker according to the invention, an adequately secure tight fit of the lug of the electrical contact element on the insulating-material housing can be realized in the end position of the electrical contact element.

Furthermore, a simple and ergonomically advantageous assembly is ensured by the insertion of the contact element into the opening in the insulating-material housing and the subsequent pivoting movement to the end position. It is also possible for a compact residual current circuit breaker with a width of only one subdivision unit per pole to be realized on account of the structural configuration of the contact element. Furthermore, the dimensions of the material cross section of the contact element can be matched to the high current intensities reguired, without relatively high levels of restrictions, with the residual current circuit breaker according to the invention.

After the contact element is inserted into the opening which is formed on the fastening face of the insulating-material housing, the contact element is in the joining position. In this case, the second end of the web of the contact element is designed to be electrically conductively connected to a primary conductor of the residual current circuit during mounting. This connection is established in the joining position by cohesive joining, for example by means of soldering or welding, of the second end of the web to the primary conductor. In this joining position, it is ensured that the high energy input, which is reguired on account of the soldering or welding of the joining partners, does not lead to any damage to the insulating-material housing or other components of the residual current circuit breaker. The pivoting novement of the contact element to its end position takes place after the two parts are cohesively joined.

In this case, the term "pivoting movement" is intended to be understood to mean a rotary movement of the contact element which can have a linear movement superimposed on it.

Furthermore, the term "externally arranged contact apparatus" is intended to be understood to mean a contact partner for the lug of the contact element, for example a busbar. In electrical installation distribution boards which are provided for pin-type devices, busbars of this kind are arranged beneath the supporting rail, in order to make it easier to make contact with the individual rail-mounted devices. In this connection, external" means outside the residual current circuit breaker".

In one advantageous development, the residual current circuit breaker has at least one lower terminal-receiving space and also at least one upper terminal-receiving space which is arranged opposite the lower terminal-receiving space. In this case, the lug is arranged on the insulating-material housing in the region of a lower terminal-receiving space, whereas the web is received in the upper terminal-receiving space, which is arranged opposite said lower terminal-receiving space, in the end position.

Proceeding from fastening of the residual current circuit breaker to a horizontally oriented supporting rail which is fastened, by way of its rear face, to a rear wall of an electrical installation distribution board, the residual current circuit breaker has, in the region of the upwardly oriented first narrow face and also in the region of the downwardly oriented second narrow face, in each case at least two terminal-receiving spaces which are designed to receive electrical connection terminals. Since the busbar is arranged below the supporting rail, the lug is likewise arranged in this region which is located in the region of a lower terminal-receiving space. For structure-related reasons, the connection terminal, which is replaced by the contact element, is associated with the upper terminal-receiving space which is arranged opposite. On account of the structural configuration of the contact element, this terminal-receiving space is used to receive the second end of the web, which is connected to the primary conductor, at that point, so that a space-saving arrangement of the individual components of the residual current circuit breaker can be realized. The residual current circuit breaker can be kept compact in this way.

In a further advantageous development of the residual current circuit breaker, the electrical contact element has a holding contour which interacts with a mating contour, which is formed in a correspondingly inverse manner on the fastening face, in such a way that movement of the contact element to a securing position produces an interlocking connection which blocks the pivoting movement.

A secure tight fit of the contact element, and therefore of the lug, on the insulating-material housing of the residual current circuit breaker is ensured with the aid of the interlocking connection -which can be in the form of a plug-and-slide connection, similar to a bayonet fitting. In this case, the holding contour, which is formed on the contact element, interacts with the mating contour, which is forned on the insulating-material housing, in such a way that movement of the contact element in a first direction from the end position to the securing position produces the interlocking connection. A movement of the contact element relative to the insulating-material housing in a second direction, which runs substantially perpendicular to the first direction, is effectively prevented with the aid of this interlocking connection. Therefore, it is no longer possible for the contact element to pivot back to the joining position.

In a further advantageous development of the residual current circuit breaker, the electrical contact element has a securing element which can be moved from a first position to a second position in which it interacts with a mating element, which is formed on the fastening face, in such a way that the contact element is fixed in the securing position in an interlocking manner.

To prevent the electrical contact element from returning from the securing position to the end position, the contact element has a securing element which can be moved from a first, neutral position to a second position. In this second position, the said securing element interacts with & mating element, which is formed on the fastening face, of the residual current circuit breaker in such a way that the contact element is fixed to the insulating-material housing in an interlocking manner in the securing position. In this case, the securing element can be integrally formed, for example, on the contact element and is pushed, by way of bending or caulking with a corresponding tool, into the mating element which, by way of example, is in the form of a pocket-like recess, which is arranged at a corresponding point, in the insulating-material housing. This produces an interlocking connection between the securing element and the mating element, and therefore between the contact element and the insulating-material housing, in a simple manner. Movement of the contact element relacive to the insulating-material housing in the first direction is effectively suppressed by this securing connection which acts in an interlocking manner.

In a further advantageous development of the residual current circuit breaker, the lug is designed in a manner angled in an L-shape and has a first limb for making electrical contact with the external contact apparatus, and has a second limb for fixing the contact element to the insulating-material housing.

The L-shaped design of the lug is a structurally simple and cost-effective possible configuration in which the various functions of the lug are shared between the two limbs: while the first limb is intended for electrical contact to be made with the contact element by the external contact apparatus, the second limb serves to fix the lug -and therefore the contact element -to the insulating-material housing of the residual current circuit breaker. A secure tight fit of the contact element on the insulating-material housing is ensured in this way.

In a further advantageous development of the residual current circuit breaker, the holding contour is formed on the second limb. The arrangement of the holding contour on the second limb of the lug which is bent in an b-shape is a structurally simple -10 -and cost-effective embodiment for realizing an interlocking first connection for blocking the pivoting movement of the electrical contact element.

In a further advantageous development of the residual current circuit breaker, the securing element is fcrmed on the second limb. The arrangement of the securing element of the second limb of the lug which is angled in an f-shape is also a structurally simple and cost-effective embodiment for realizing an interlocking second connection, in order to prevent the electrical contact element from returning from the securing position to the end position.

In a further advantageous development of the residual current circuit breaker, an insulation element is arranged in the insulating-material housing in such a way that the web is electrically insulated, at least in sections, from further components of the residual current circuit breaker.

The web of the electrical contact element is advantageously routed along in the immediate vicinity of one of the broad sides of the insulating-material housing. In this case, the insulation element serves to electrically insulate the electrical contact element from further components of the residual current circuit breaker which are arranged in the interior of the insulating-material housing. In this case, the insulation element can be integrally connected to the relevant part of the insulating-material housing. However, it is likewise possible to design the insulation element as an independent component which is fastened to the housing in a suitable manner. Tn this way, the formation of different housing variants can be moved to the final assembly stage from a manufacturing point of view, so that fewer different basic housing types have to be kept available.

-11 -In a further advantageous development of the residual current circuit breaker, the second end of the web has a receptacle for forming a cohesive connection with the primary conductor.

The second end of the web is provided for a cohesive connection, in particular a soldered or welded connection, to a primary conductor of the residual current circuit breaker. Both in the case of & soldered connection and also in the case of a welded connection, it is advantageous to not join the parts, which are to be joined, to one another in a planar manner, but rather to position them -at least in respect of one dimension -in relation to one another in an interlocking manner in order to achieve a connection which is as stable as possible. This can be achieved, for example, by a receptacle which is formed on one of the joining partners and into which the other joining partner is inserted. In the present case, the second end of the web has a receptacle of this kind into which an end of the primary conductor, which end has been stripped of insulation, is inserted in order to be connected to the second end of the web by a soldering or welding process.

In order to further simplify the joining process, the receptacle is advantageously formed in a v-shape. In order to optimize the positioning of the joining point in the terminal-receiving space, the second end of the web is angled relative to its direction of longitudinal extent, preferably at an angle of between 100 and 30° with respect to the direction of longitudinal extent.

In a further advantageous development of the residual current circuit breaker, the electrical contact element is integrally formed, for example as a stamped and bent part. The design as a stamped and bent part is an extremely cost-effective way of producing the electrical contact element in a simple and automated manner.

-12 -In a further advantageous development of the residual current circuit breaker, the opening is largely closed in its end position by the electrical contact element.

At least one switching contact, which opens in the event of tripping and therefore interrupts the flow of current, is also generally arranged within the residual current circuit breaker.

If a current-carrying switching contact is opened, an arc is produced in the process. It is therefore necessary, for reasons of safety, to keep the insulating-material housing closed as far as possible during operation. This is true particularly in the region of the switching chamber in which the switching contact is arranged. Since the opening which is formed in the insulating-material housing is closed by the contact element itself in the end position after the contact element is inserted, an additional closure means can be dispensed with.

In a further advantageous development of the residual current circuit breaker, the insulating-material housing can be produced by means of a plastic injection-moulding process.

Production of the insulating-material housing using the plastic injection-moulding process is a simple and cost-effective option. However, a correspondingly suitable structural configuration of the housing, that is to say one without an undercut, is a prereguisite.

The assembly method according to the invention for assembling a residual current circuit breaker of the kind described above comprises the steps of: a) inserting the web into the opening, which is formed on the fastening face of the insulating-material housing, wherein a joining position is achieved, b) cohesively joining the second end to a primary conductor of the residual current circuit breaker, c) pivoting the electrical contact element to an end position.

-13 -With the aid of the assembly method according to the invention, it is possible to assemble the residual current circuit breaker according to the invention in as simple and cost-effective a manner as possible. To this end, the web is inserted into the opening, which is formed on the fastening face of the insulating-material housing, In a first step. This is performed on the basis of a substantially linear movement which can be executed both manually and also in an automated manner.

If the oontact element, relative to the insulating-material housing, is in its joining position, the second end of the web is cohesively joined to an end, which is srripped of insulation, of the primary conductor in a second step. A soldering or welding method which, once again, can be executed both manually and also in an automated manner is preferably used in this case.

The electrical contact element is pivoted to its end position, in which the joining point is received in one of the terminal-receiving spaces of the residual current circuit breaker, in a third step only when the two joining partners are fixedly connected to one another.

In one advantageous development, the assembly method comprises the further steps of: d) moving the contact element to a securing position, and e) securing the contact element in the securing position by moving the securing element from its first position to its second position.

The contact element is moved from its end position to the securing position on the basis of a substantially linear movement -relative to the insulating-material housing -of the contact element in the first direction to its securing position. On account of the resulting interlocking connection between the retaining contour of the contact element and the mating contour which is formed on the insulating-material -14 -housing, the contact element is effectively prevented from pivoting back to its joining position. The contact element is then secured in this securing position by the securing element, which is formed on the contact element, being moved from its first position to its second position. As a result, a second interlocking connection is formed between the contact element and the insulating-material housing, said second interlocking connection preventing the contact element from sliding back to its end position. In this way, a secure tight fit of the electrical contact element of the insulating-material housing of the residual current circuit breaker can be realized using a small number of assembly steps which are simple to execute.

In a further advantageous development of the assembly method, the primary conductor is routed through a core-balance current transformer of the residual current circuit breaker before being joined to the second end of the web. This provides the advantage that the core-balance current transformer with the primary conductor routed through it is already prcvided as a preassembled module. Therefore, pivoting the electrical contact element to its end position also moves the core-balance current transformer to its final position. The assembly process is further simplified as a result.

One exemplary ertodiment of the residual current circuit breaker is explained in greater detail below with reference to the appended figures, in which: figure 1 is a schematic illustration of a side view of the residual current circuit breaker according to the invention; figures 2A and 23 are schematic illustrations of various views of the open residual current cirdilit breaker; figures -15 - 3A to 3C are schematic illustrations of various views of the electrical contact element; figure 4 is a schematic, perspective illustration of the fastening face of the residual current circuit breaker; and figures 5A to SD are schematic illustraticns relating to the mounting process for the electrical contact element.

In the various figures of the drawings, identical parts are always provided with the same reference symbol. The description applies to all figures of the drawing in which the corresponding part is likewise shown.

Figure 1 shows a schematic illustration of a side view of the residual current circuit breaker 1 according to the invention.

In this case, the residual current circuit breaker 1 is designed as a rail-mounted device, that is to say it is designed to be fastened to a supporting or top-hat rail in an electrical installation distribution board. To this end, the residual current circuit breaker 1 has an insulating-material housing 2 which, for its part, substantially comprises a first housing shell 2-1, into which the components of the residual current circuit breaker 1 can be inserted during assembly, and also a second housing shell 2-2 which is configured as a covering element. The first housing shell 2-1 and the second housing shell 2-2 are connected to one another by means of a plurality of connecting means 8, which are arranged in the region of a joining line 19 of the two housing shells, in order to complete assembly of the device. In the case illustrated at present, these connecting means 8 are in the form of latching connections in which in each case one snap-action hook, which is formed on the first housing shell 2-1, engages into a snap- -16 - action opening, which is formed on the second housing shell 2- 2, in order to latch the two housing shells to one another.

An operating element 3 for manually operating the residual current circuit breaker 1 is formed on a front face 4 of the insulating-material housing 2. The fastening face 5 is arranged opposite the front face 4, the said fastening face serving to fasten the residual current circuit breaker 1 to a supporting element, for example a supporting or top-hat rail of an electrical installation distribution board. To this end, the residual current circuit breaker 1 has a fastening means 9 which is arranged such that it can move on the insulating-material housing 2 in the region of the fastening face 5 and is designed to engage behind the supporting or top-hat rail. In this way, the residual current circuit breaker 1 can be fastened to the supporting rail or detached from said supporting rail by moving the fastening means 9. Furthermore, the insulating-material housing 2 has two narrow faces 6 and also two broad faces 7 which connect the front face 4 to the fastening face 5.

Furthermore, an electrical contact element 20, a so-called pin, is routed out of the insulating-material housing 2 from the fastening face 5. The illustrated residual current circuit breaker 1 is therefore a so-called pin-type device in which one of the electrical connection terminals has been replaced by a pin. During mounting of the residual current circuin breaker 1 in an electrical installation distribution board, the electrical connection in question no longer has to be clamped by means of a screw terminal as a cable. Instead, the pin is inserted into a busbar which is arranged below the supporting or top-hat rail, so as to form an electrical contact. As a result, the complexity of mounting is firstly clearly simplified, and secondly considerably less installation space is required for the copper cables in the electrical installation distribution board when a busbar is used, and -17 -therefore the distribution board can be configured in a more compact manner.

In the present case, the insulating-material housing 2 substantially comprises two parts, the first housing shell 2-i and also the second housing shell 2-2. However, it is likewise possible for the insulating-material housing 2 to be formed from more than two parts. It is likewise possible to hold the individual housing parts of the insulating-material housing 2 together using other or additional connecting means, for example by means of rivet connections.

Figures 2A and 2B show schematic illustrations of various views of the open residual current circuit breaker 1. With respect to the insulating-material housing 2, said figures illustrate only the first housing shell 2-1, the second housing shell 2-2 having been omitted in order to provide a view into the open housing. The first housing shell 2-1 of the residual current circuit breaker 1 has, in the region of its narrow faces 6, in each case two terminal-receiving spaces 10 in which electrical connection terminals 11 can be received and held. Proceeding from mounting of the residual current circuit breaker 1 on a horizontally oriented supporting or top-hat rail which is fastened to a rear wall of an electrical installation distribution board by way of its rear face, the residual current circuit breaker 1 is arranged upright in the electrical installation distribution board and points forward by way of its front face 4. In this position, the residual current circuit breaker 1 has, in the region of its upper and lower narrow faces 6, in each case two terminal-receiving spaces 10 for receiving electrical connection terminals. In order to be able to better distinguish between them, these terminal- receiving spaces 10 are therefore designated lower terminal- receiving spaces 10-i" and "upper terminal-receiving spaces 10-2".

-18 -A toroidal core-balance current transformer 16 through which two primary conductors 12 are routed is arranged centrally between the lower terminal-receiving spaces 10-1 and the upper terminal-receiving spaces 10-2. In this case, the primary conductors can also be routed through the torus of the core-balance current transformer 16 several times. Two switching chambers 18 are arranged between the core-balance current transformer 16 and the two lower terminal-receiving spaces 10- 1, in each case one switching contact (not illustrated) being received in said switching chambers and the electric current which is carried by means of the primary conductors 12 being interrupted with the aid of said switching contacts when the residual current circuit breaker 1 is tripped.

However, in the case of the residual current circuit breaker 1 according to the invention, not all terminal-receiving spaces are fitted with electrical connection terminals 11: whereas the two lower terminal-receiving spaces 10-1 are fitted with in each case one connection terminal 11, a connection terminal 11 is received in the upper terminal-receiving spaces 10-2 only at the top-right terminal-receiving space. The electrical contact element 20 is routed out of the insulating-material housing 20 in the immediate vicinity of the lower terminal-receiving spaces 10-1 and also the switching chambers 18. In the interior of the insulating-material housing 2, the contact element 20 is routed along a broad side 7 of the insulating-material housing 2 in the direction of the top-left terminal receiving space 10- 2, where it is electrically conductively connected to one of the primary conductors 12. In order to electrically insulate the contact element 20, in particular, from the primary conductors 12 which are wound around the core-balance current transformer 16, the insulating-material housing 2 has, in the affected region, an insulation element 17 which is routed from the region of the switching chamber 18 to the region of the upper terminal-receiving space 10-2 parallel to the broad side 7. In this case, the insulation element 17 can be both -19 -integrally formed on the first housing shell 2-1 or be subsequently mounted as an individual component.

The arrangement illustrated in figures 2A and 2B with a contact element 20 which is routed out of the insulating-material housing 2 in the region of the lower terminal-receiving spaces li-i and which replaces a connection terminal iL which is received in one of the upper terminal-receiving spaces 11-2 is essential in this case: firstly, the busbar is arranged below the supporting rail in the electrical installation distribution board as standard, and therefore the contact element 20 also necessarily has to be arranged in this region, that is to say in the region of the lower terminal-receiving spaces 10-1.

Secondly, the busbar replaces an electrical connection with which it would otherwise be necessary for a connection terminal 11, which is arranged in one of the upper terminal-receiving spaces 11-2, to make contact.

Figures 3A to 30 schematically illustrate various views of the electrical contact element 20. In the present case, the contact element 20 is designed as a stamped and bent part which is composed of electrically conductive material and has a lug 21 on which a web 22 is integrally formed. The lug 21 is angled in an L-shape, having a first limb 21-1 for making electrical contact with the busbar, and also having a second limb 21-2 which is designed for fixing the contact element 20 to the insulating-material housing 2. To this end, the second limb 21- 2 firstly has a securing element 24 which can be moved from a first position to a second position. In this second position, the securing element 24 interacts with a mating element 14 (see figure 4A) , which is formed on the fastening face 5 of the insulating-material housing 2, in such a way that The contact element 20 is fixed in a first direction x in an interlocking manner. Secondly, the second limb 21-2 has a holding contour 23 which has two lateral cutouts 23-1 and interacts with a mating contour 13 (see figure 4A) , which is forned in a correspondingly inverse manner on the fastening face, in such a -20 - way that the contact element 20 is held on the insulating-material housing 2 in a second direction y and also a third direction z in an interlocking manner. In this case, the holding contour 23 interacts with the mating contour 13 in such a way that the contact element 20 is still able to move only in the first direction x. The three directions x, y and z correspond to the orientation directions of the coordinate axes of a Cartesian coordinate system in this case.

The web 22 has a first end 22-1 which is integrally formed on the second limb 21-2 of the lug 21 and is bent over through an angle of approximately 90° in comparison to the second limb 21- 2. Furthermore, the web 22 has a second end 22-2 which is intended to be electrically conductively connected to one of the primary conductors 12 of the residual current circuit breaker 1. To this end, the second end 22-2 has a v-shaped receptacle 25 into which an end, which is stripped of insulation, of the primary conductor 12 is inserted -during mounting of the residual current circuit breaker 1 -in order to then be electrically conductively connected to contact element 20 by means of a cohesive joining method, for example welding or soldering. The first end 22-1 and the second end 22- 2 are electrically conductively connected to one another by means of an elongate main body 22-3 of the web 22. In order to ensure simple mounting of the contact element 20 in the insulating-material housing 2, the second end 22-2 of the web 22 is angled, preferably at an angle of between 10° and 30°, relative to a direction of longitudinal extent of the main body 22-3 which runs parallel to the direction x in the mounted state. In this way, the second end 22-2 can be received in the top-left terminal-receiving space 10-2, and at the same time the main body 22-3 is guided along the broad face 7 of the insulating-material housing 2 as closely -and therefore in as space-saving a manner -as possible.

Figure 4 schematically shows a perspective illustration of the fastening face 5 of the residual current circuit breaker 1. The -21 -fastening means 9, which serves to fasten and release the residual current circuit breaker 1 to and, respectively, from the supporting rail, is arranged, in a manner mounted such that it can move in the x-direction, on the fastening face 5, in the region of the broad side 7 which is depicted as lying at the bottom. In the region of the broad side 7 which is depicted as lying at the top, an opening 15 is formed in the fastening face of the insulating-material housing 2, the web 22 of the electrical contact element 20 being routed through the said opening during assembly of the residual current circuit breaker 1. In addition, the mating contour 13 can be seen in the region of the narrow face 6, the said mating contour interacting with the retaining contour 23, which is formed on the first limb 21- 1, in such a way that the contact element 20 is received both in the direction y and in the direction z in an interlocking manner. To this end, the mating contour has two web-like guide contours 13-1 and also two flat holding contours 13-2.

In order to also realize an interlocking connection between the contact element 20 and the insulating-material housing in the direction x, the fastening face 5 has, in the region of the mating contour 13, a mating contour 14 which is in the form of a pocket-like recess which interacts with the securing contour 24 of the contact element 20. In this case, the securing contour 24, which is formed on the first limb 21-1 of the lug 21, is pushed into the pocket-like recess in the mating contour 14, so that an interlocking connection is formed, this interlocking connection effectively preventing movenent of the contact element 20 relative to the insulating-material housing 2. This interlocking connection can be established, for example, by means of caulking the securing element 24 which is in the form of a v-shaped lug.

Figures 5A to SD show schematic illustrations relating to the mounting process for the contact element 20 with the first housing shell 2-1 of the insulating-material housing 2. In this case, the ability to mount pin-type devices constitutes a not -22 -inconsiderable problem since the external pin cannot be connected to the internal components by a simple plug connection on account of the high current intensities which have to be withstood. Instead, a connection to the primary conductor which is suitable for high currents is required, and for this reason cohesive joining methods, such as welding or soldering, are used to establish this connection. However, a welded or soldered connection of this kind cannot be generated within the insulating-material housing 2 since the high energy reguired for this purpose would result in thermal damage to the housing. For this reason, the web 22 of the contact element 20 is -in a first step -first inserted into the opening 15, which is formed in the fastening face 7, as far as possible by virtue of a substantially linear movement. At the end of this movement, the contact element 20 reaches its joining pcsiticn which is illustrated in figure 5A.

In this joining position, the second end 22-2 of the web 22 is then cohesively joined to the associated primary conductor 12, preferably by means of soldering or welding. The high energy input of the cchesive joining method which is used in the process is unproblematical in as much as the parts which are to be joined are at a sufficient distance from the first housing shell 2-1 of the thermally sensitive insulating-material housing 2. The primary conductcr 12 is advantageously already routed through the core-balance current transformer 16 before being joined to the second end 22-2, and then mounted together with the core-balance current transformer 16 as a preassembled transformer assembly.

The contact element 20 is then pivoted relative to the first housing shell 2-1, until it is in its end position which is illustrated in figures 2A and 2B. In this case, the pivcting movement substantially represents a rotary or tilting movement of the contact element 20 in the opening 15 in the first housing shell 2-1. In the end position, the second end 22-2, which is now cohesively connected to the primary conductor 12, -23 -is received in the top-left terminal-receiving space 10-2. A detailed illustration of the fastening face 7, in which the contact element 20 is located in this end position, is schematically illustrated in figures SB and 50. It is clear that, when the contact element 20 is pivoted into the end position, the two web-like guide contours 13-1 of the mating contour 13 interact with the cutouts 23-1, which are formed on the second limb 21-2 of the contact element 20, in such a way as to guide the contact element 20 in the second direction y in a last portion of the pivoting movement, until the contact element 20 has reached its end position.

Once the contact element 20 has reached its end position, the contact element 20 is moved to its securing position, which is illustrated in figure SD, by a substantially linear movement of the contact element 20 relative to the insulating-material housing 2 of the residual current circuit breaker 1 in the first direction x. In this securing position, both the two guide contours 13-1 and the two holding contours 13-2 now both act on the second limb 21-2 in an interlocking manner, so that a relative movement of the contact element 20 relative to the insulating-material housing 2 is effectively prevented both in the second direction y and in the third direction. Therefore, a plug-and-slide connection, which acts similarly to a bayonet fitting, is formed between the second limb 21-2 and the insulating-material housing 2. In the present case, the holding contour 23 and the mating contour 13 interact in such a way that, after the two cutouts 13-1 are inserted into the guide contours 23-1 and the contact element 20 is then moved into the securing position, an interlocking connection, which acts in the second direction y and also in the third direction z, is formed.

In order to suppress a movement of the contact element 20 relative to the insulating-material housing 2 in the first direction too, and therefore to fix the contact element 20 to the insulating-material housing 2 in all three directions, the -24 -securing element 24, which is in the form of a v-shaped lug, is pressed into the mating element L4, which is in the form of a pocket-like recess, in the securing position. This can be done, for example, by means of caulking using a tool which is suitable for this purpose. In this case, the term caulking" is intended to be understood to mean establishing a force-fitting and interlocking connection between two individual workpieces by plastic deformation -in this case by pushing the securing element 24 into the pocket-like recess 14.

-25 -List of reference symbols: 1 Residual current circuit breaker 2 Insulating-material housing 2-1 First housing shell 2-2 Second housing shell 3 Operating element 4 Front face Fastening face 6 Marrow face 7 Broad face 8 Connecting means 9 Fastening means Terminal-receiving space 10-1 Lower terminal-receiving space 10-2 Upper terminal-receiving space 11 Connection terminal 12 Primary conductor 13 Mating contour 13-1 Guide contour 13-2 Holding contour 14 Mating element Opening 16 Core-balance current transformer 17 Insulation element 18 Switching chamber 19 Joining line Contact element 21 Lug 21-1 First limb 21-2 Second limb 22 Web 22-1 First end 22-2 second end 22-3 Main body 23 Holding contour 23-1 Cutout -26 - 24 Securing element Receptacle x First direction x / x direction y Second direction y / y direction z Third direction z / z direction