WO2015147731A1

WO2015147731A1 - Electric connection device for connection of a ground wire to a safety ground

Info

Publication number: WO2015147731A1
Application number: PCT/SE2015/050343
Authority: WO
Inventors: Magnus Karlsson
Original assignee: Magnus Karlsson
Priority date: 2014-03-24
Filing date: 2015-03-23
Publication date: 2015-10-01
Also published as: SE537895C2; SE1450337A1

Abstract

An electric connection device (300) for connection of a grounding conductor (320) to a connection point of a safety ground, wherein the connection device comprises a connection member (301) configured to be connected to the grounding conductor and an electrically conducting member (302) associated with the connection member and configured to establish electrical contact between a grounding conductor connected to the connection member and the connection point. The electrically conducting member is extendable and comprises at a first end means (303) for mechanically and electrically fixedly connect the connection device to the connection point and is at a second end mechanically and electrically fixedly connected to the connection member. The connection device comprises an attachment member (311) to releasably fix the connection member with respect to the connection point, so that the connection member, when fixed with respect to the connection point and when a pulling force is applied to the connection member connected grounding conductor, is arranged to be released from the fixation with respect to the connection point so that the electrically conducting member is extended while the grounding conductor maintains electrical contact with the safety ground.

Description

Electric connection device for connection of a grounding conductor to a safety ground

FI ELD OF THE I NVENTION

The present invention relates to an electric connection device for fixed connection of at least one grounding conductor to a connection point of a safety ground according to the preamble of claim 1 .

BACKROUN D OF THE I NVENTION AND PRIOR ART

In fixed electric connections in which a cable with a plurality of conductors, including phase conductors, a possible neutral conductor and a grounding conductor, is to be connected to for example busbars in an installation in the form of a distribution board , a wiring closet, a substation or the like, the connection is to be configured so that the grounding conductor is the last conductor to come off if the cable is pulled or torn out. The purpose of this is that no conducting part of the installation should become involuntarily live, which puts the security in the installation at risk. In order to make sure that the grounding conductor is the last one to come off from the installation , the grounding conductor is usu- ally made longer than the other conductors of the cable. This results in additional work during installation and it also requires additional space in the installation . It is also easy to overlook making the grounding conductor longer than the remaining conductors, which results in security problems with the installation . It is there- fore desirable to overcome these drawbacks.

SUM MARY OF THE I NVENTI ON

An object of the present invention is to provide an electric con- nection device by means of which the above-mentioned draw- backs can be avoided or at least reduced . Such a connection device is achieved by the initially defined connection device, which is characterized in that the electrically conducting member is extendable and at a first end comprises means for mechanically and electrically fixedly connect the connection device to said connection point and at a second end is mechanically and electrically fixedly connected to the connection member, and that the connection device further comprises at least one fastening member for releasably fixing the at least one connection member with respect to said connection point, so that the connection member, when fixed with respect to the connection point and when a pulling force is applied to a grounding conductor connected to the connection member, is arranged to be released from the fixation with respect to the connection point so that the electrically conducting member is extended while the grounding conductor maintains electrical contact with the safety ground .

In an electric connection device according to the invention , the elongation of the grounding conductor is thereby included in the form of the extendable electrically conducting member. Upon connection of the conductors of a cable to, for example, each of the phase busbars and the ground bar of an installation , the grounding conductor can thereby be made as short as the other conductors. In order to connect the phase conductors and a possible neutral conductor to the associated busbar, conventional connection terminals without included extendable conducting member are used . When pulling on the cable with sufficient pulling force, the phase conductors come off from their associated connection points on the phase busbars and the electrical contact between phase busbars and phase conductors is broken , while simultaneously the connection member comes off the connection point of the safety ground . The grounding conductor remains however in electrical contact with the connection point of the fixed safety ground , since the extendable electrically conducting member is extended and thereby ensures that the electrical contact is not broken between the grounding conductor and the safety ground . Only after the phase conductors have come off their associated connections, and the installation is thereby no longer live, the grounding conductor comes off the connection device and the grounding circuit is broken .

Thanks to that the extension of the grounding conductor is built into the connection device, the electric installation work is facilitated while the security is increased . Furthermore, space can be saved in the installation since the built-in grounding conductor in the form of the extendable electrically conducting member can be made less bulky than an elongated grounding conductor.

According to an embodiment of the invention , the electrically conducting member consists of a grounding braid . The grounding braid is strong and yet flexible and is thereby easy to arrange extendable by means of for example folding or rolling . The grounding braid can preferably be a copper braid , which results in good electrical properties. The grounding braid can also be a tinned copper braid , which has good durability.

According to an embodiment of the invention , the electrically conducting member is configured to be extendable by unfolding from a folded state to an unfolded state. By means of this embodiment, a simple and quick way of extending the electrically conducting member is achieved . Alternatively, the electrically conducting member can be configured to be extendable by means of for example rolling .

According to an embodiment of the invention , the at least one connection member is releasably fixed with respect to the connection point by means of being releasably attached to the main portion by means of said fastening member. In this embodiment, the first end of the electrically conducting member is attached to the main portion , which in turn is attached to the connection point of the fixed safety ground . Thereby, the attachment of the connection device is facilitated . According to an embodiment of the invention , the connection device comprises a main portion configured to fixedly connect the connection device to the connection point, wherein the electrically conducting member extends between the main portion and the associated connection member. A simplified connection to the safety ground can thereby be achieved .

According to a further embodiment of the invention , the at least one connection member is releasably fixed with respect to the safety ground by means of being releasably attached to the main portion by means of said fastening member. In this way, the connection member or the connection members is/are releasably attached to the connection point of the safety ground via the main portion . Upon a sufficiently powerful pull on the cable with the grounding conductor, the connection member will come off the main portion , which is still attached to the fixed safety ground . This facilitates the installation in installations such as wiring closets, distribution boards and substations since the connection de- vice can be treated as a unity.

According to an embodiment of the invention , the main portion is in the form of a ground bar. By designing the main portion as a ground bar, several connection members can be accommodated next to each other in one connection device. This kind of connection device is furthermore suitable to be permanently installed in an existing installation with phase busbars.

According to an embodiment of the invention , the main portion comprises at least one recess for receiving the at least one connection member. The connection device can thereby be made compact and space efficient.

According to an embodiment of the invention , the connection de- vice comprises at least two connection members. In this embodiment, the connection device provides a space efficient way of connecting two or more grounding conductors to fixed connection points of a safety ground . Furthermore, the installation is facilitated in comparison with using separate connection devices for each grounding conductor. Preferably, the connection device comprises at least four connection members, more preferably at least six connection members.

BRI EF DESCRI PTION OF THE DRAWI NGS

The invention will in the following be described with reference to the appended drawings, in which

Fig . 1 shows a connection device according to a first embodiment of the invention ,

Fig . 2 shows the connection device of Fig . 1 with the electrically conducting member extended ,

Fig . 3 shows an exploded view of the connection device in

Fig . 1 ,

Fig . 4a-b shows a connection device according a second embodiment of the invention , and Fig . 5 shows a connection device according to a third embodiment of the invention .

DETAI LED DESCRI PTI ON OF EMBODI M ENTS OF THE I NVENTION

A connection device 100 according to a first embodiment of the invention is schematically shown in Fig . 1 -3. The connection device 100 comprises a connection member 101 for connection of a grounding conductor (not shown) by means of a screw 105. The connection member 101 is attached to one end of a grounding braid 102, which is arranged folded in a recess 1 19 of a main portion 103 together with the connection member 101 . The second end of the grounding braid 102 is attached to a back portion 104 of the main portion . The main portion 103 is here provided with a screw hole 106 for attachment of the main portion 103 to a fixed connection point of a safety ground in the form of for example a safety ground bar (not shown). The main portion 103 has two side portions 107, 108 which delimit the recess 1 19 accommodating the grounding braid 102 and the connection member 101 . In the side portions 107, 108, recesses 109 are provided , which are designed for engagement with attachment members 1 1 1 . The attachment members 1 1 1 enclose the lower edge of each side portion 107, 108 respectively and form support surfaces 1 1 1 a protruding thereunder, which hold the connection member 101 in its position in the main portion 103. The connection mem- ber 101 , the grounding braid 102 and the main portion 103 are made from an electrically conducting material , for example copper. The attachment members 1 1 1 can on the other hand be made from plastic or some other material . When the main portion 103 has been screwed onto a fixed connection point of a safety ground , a grounding conductor is mounted in the connection member 101 . The grounding conductor is thereby via the grounding braid 102 electrically connected to the safety ground . When a grounding conductor mounted in the connection member 101 is subjected to a pulling force in the form of for example a downward pull , the attachment members 1 1 1 are pressed downward and disengage with the recesses 109. Thereby, also the connection member 101 comes off its position in the main portion 1 03 and the grounding braid 102 is unfolded , as shown in Fig . 2. Not until the grounding braid 102 is fully unfolded , the grounding conductor comes off the connection member 101 .

Another embodiment of a connection device according to the in- vention is schematically shown in Fig . 4a-b. In this embodiment, the connection device 200 comprises a main portion 203 configured to be attached to a fixed connection point of safety ground (not shown ), a connection member 201 for connection of a conductor (not shown) by means of a screw 205, and a grounding braid 202 which electrically connects the main portion 203 and the connection member 201 . The connection device 200 further comprises an attachment member 21 1 for releasably attaching the connection member 201 to the main portion 203. The connection device 200 differs from the connection device 100 according to the first embodiment by for example the design of the main portion 203. The main portion 203 lacks in this embodiment sidewalls. A back portion 204 of the main portion 203 is configured to abut an abutment surface (not shown) of the con- nection member 201 with an abutment surface 204a. The abutment surface 204a is designed with a surface structure in the form of triangular countersinks 215 and the abutment surface of the connection member 201 is designed with a corresponding surface structure in the form of triangular protrusions designed for en- gagement with the countersinks 215. The grounding braid 202 is arranged hanging between the connection member 201 and the main portion 203. The attachment member 21 1 is arranged to enclose an upper portion 210 of the connection member 201 with an upper portion 21 2 and at the same time partly enclose the back portion 204 of the main portion 203. The attachment member further comprises a lower portion 213 with two side portions 213a , 213b. In each side portion 213a, 21 3b, a protruding portion 214 is provided , which protruding portion 214 is arranged for engagement with a recess 209 provided in the connection member 201 .

Upon use of the connection device 200, a conductor is connected to the connection member 201 , which is attached to the main portion 203 by means of the attachment member 21 1 . The main portion 203 is attached to a fixed connection point of a safety ground and is thereby electrically connected to the latter. Upon a possible pull on the conductor, the connection member 201 comes off the main portion 203. The grounding braid 202, which has been hanging doubled between the main portion 203 and the connection member 201 , is thereby extended by unfolding into its full length . The electrical contact between the conductor and the main portion 203, and thereby also the fixed connection point of the safety ground , is kept until the conductor comes off its position in the connection member 201 , which will happen if the conductor is subjected to additional pulling force after the point where the grounding braid 202 has unfolded into its full length .

Another embodiment of a connection device according to the invention is schematically shown in Fig . 5. In this embodiment, the connection device 300 comprises three connection members 301 in the form of connection terminals for connecting a grounding conductor 320. Each connection member 301 is electrically connected to a common main portion 303 in the form of a ground bar by means of a grounding braid 302 associated with each of the connection members respectively. The connection members 301 are moulded into attachment members 31 1 configured for en- gagement with recesses 309 provided in the main portion 303. To be able to releasably attach the attachment members 31 1 to the main portion 303, the side edges 313 of the attachment members are designed with a transverse edge 314 which , when the attachment members are engaged with the recesses 309 of the main portion rests on edges 316 arranged in the recesses 309. The edges 314, 316 are configured so that the attachment member 31 1 comes off the main portion 303 upon a pull on a grounding conductor 320 attached to the connection member 301 . Via the connection member 301 , the grounding braid 302 and the main portion 303, the electrical contact with a fixed connection point of a safety ground (not shown ) connected to the main portion 303 is retained .

In all of the shown embodiments, the connection member, the grounding braid and the main portion are made from an electrically conducting material , for example copper or tinned copper. The attachment members do however not need to be electrically conducting and can be made from plastic or some other material . The connection member can for example be in the form of a connection terminal , in which the grounding conductor is clamped by means of a quick wire connector or by means of a screw in order to establish electrical contact with the electrically conducting member, or in the form of a built-in connection block.

The grounding conductor which is connected by means of the con- nection device can be a pure protective earth , a so-called PE- conductor, but it can also be a combined protective earth and neutral conductor, a so-called PEN-conductor, depending on which conductor system is used . The connection point of the safety ground to which the grounding conductor is to be con- nected can for example be located on a ground bar made from for example brass or copper, but it can also be a connection point of another conductor that functions as a safety ground . The mounting of the connection device at the fixed connection point of the safety ground can be carried out by means of for example a screw or by clamping .

The connection device according to the invention is primarily intended for installations in the form of for example distribution boards, wiring closets, substations or the like, in which a cable is fixedly connected to connection points in the installation . The connection device can however also be used in installations in the form of electronic equipment, domestic appliances and the like. The invention is of course not limited to the embodiments described above. On the contrary, these are only to be regarded as examples which can be modified within the frame of the appended claims.

Claims

1 . An electric connection device (100, 200, 300) for fixed connection of at least one grounding conductor (320) to a con- nection point of a safety ground , wherein the connection device comprises:

- at least one connection member (101 , 201 , 301 ) configured to be connected to a said grounding conductor (320);

- an electrically conducting member (102, 202, 302) associ- ated with each of the connection members (101 , 201 , 301 ), respectively, and configured to establish electrical contact between a grounding conductor (320) connected to the connection member (101 , 201 , 301 ) and the connection point;

characterized in

that the electrically conducting member (1 02, 202 ,302) is extendable and at a first end comprises means (1 03, 203, 303) for mechanically and electrically fixedly connect the connection device (100, 200, 300) to said connection point and at a second end is mechanically and electrically fixedly connected to the connection member (1 01 , 201 , 301 ), and that the connection device further comprises at least one fastening member (1 1 1 , 21 1 , 31 1 ) for releasably fixing the at least one connection member (101 , 201 , 301 ) with respect to said connection point, so that the connection member (101 ,

201 , 301 ), when fixed with respect to the connection point and when a pulling force is applied to a grounding conductor (320) connected to the connection member (101 , 201 , 301 ), is arranged to be released from the fixation with respect to the connection point so that the electrically conducting member (102 , 202 , 302) is extended while the grounding conductor (320) maintains electrical contact with the safety ground .

2. The electric connection device according to claim 1 , charac- terized in that the electrically conducting member (102, 202 ,

302) consists of a grounding braid . The electric connection device according to claim 1 or 2, characterized in that the electrically conducting member (102, 202, 302) is configured to be extendable by unfolding from a folded state to an unfolded state.

The electric connection device according to any one of the preceding claims, characterized in that the connection device (100, 200, 300) comprises a main portion (103, 203, 303) configured to fixedly connect the connection device to the connection point, wherein the electrically conducting member (102, 202 , 302) extends between the main portion (103, 203, 303) and the associated connection member (101 , 201 , 301 ).

The electric connection device according to claim 4, characterized in that the at least one connection member (101 , 201 , 301 ) is releasably fixed with respect to the connection point by means of being releasably attached to the main portion (103, 203, 303) by means of said fastening member (1 1 1 , 21 1 , 31 1 ).

The electric connection device according to any one of claims

4 to 5, characterized in that the main portion is in the form of a ground bar.

The electric connection device according to any one of claims

5 to 6, characterized in that the main portion (1 03, 303) comprises at least one recess (1 1 9, 309) for receiving the at least one connection member (101 , 301 ).

The electric connection device according to any one of the preceding claims, characterized in that it comprises at least two connection members (301 ).