EP1323211A1 - Link box and method of manufacturing the same - Google Patents

Link box and method of manufacturing the same

Info

Publication number
EP1323211A1
EP1323211A1 EP01969928A EP01969928A EP1323211A1 EP 1323211 A1 EP1323211 A1 EP 1323211A1 EP 01969928 A EP01969928 A EP 01969928A EP 01969928 A EP01969928 A EP 01969928A EP 1323211 A1 EP1323211 A1 EP 1323211A1
Authority
EP
European Patent Office
Prior art keywords
link box
resin
spigots
cable
link
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP01969928A
Other languages
German (de)
French (fr)
Other versions
EP1323211B1 (en
Inventor
John Dockray
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tyco Electronics UK Ltd
Original Assignee
Tyco Electronics UK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tyco Electronics UK Ltd filed Critical Tyco Electronics UK Ltd
Publication of EP1323211A1 publication Critical patent/EP1323211A1/en
Application granted granted Critical
Publication of EP1323211B1 publication Critical patent/EP1323211B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R9/00—Structural associations of a plurality of mutually-insulated electrical connecting elements, e.g. terminal strips or terminal blocks; Terminals or binding posts mounted upon a base or in a case; Bases therefor
    • H01R9/22—Bases, e.g. strip, block, panel
    • H01R9/24—Terminal blocks
    • H01R9/2425—Structural association with built-in components
    • H01R9/2433—Structural association with built-in components with built-in switch
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R31/00—Coupling parts supported only by co-operation with counterpart
    • H01R31/08—Short-circuiting members for bridging contacts in a counterpart
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/46—Bases; Cases
    • H01R13/465—Identification means, e.g. labels, tags, markings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/28—Clamped connections, spring connections
    • H01R4/30—Clamped connections, spring connections utilising a screw or nut clamping member

Definitions

  • This invention relates to a so-called “link box”, that is to say to a unit intended for installation in an electrical supply cable or cables so as to permit temporary interruption of current flow along that cable or cables.
  • Link boxes are widely used where it is desired temporarily to interrupt the supply of electric current in a cable or cables, typically a three-phase AC mains supply. Such boxes are commonly installed in underground chambers in roadways or other paved areas.
  • the link box is interposed between two parts of a cable and serves to either permit or interrupt the flow of current along the cable.
  • the link box contains two sets of terminals, for the individual cores of the two parts of the cable, and a set of mechanical links are used to connect the corresponding terminals to complete the current path. Physical removal of the link interrupts the flow of current. More complex arrangements are also possible in which a number of cables are connected to the link box and a variety of possible connections can be achieved by the use of appropriate links.
  • link boxes were connected to the supply cable in situ. By this is meant that a break was made in the cable, the ends of the cable cores were exposed and connected directly into the link box. After all the connections had been made, the link box was filled with a resin which surrounded and insulated the connections.
  • Such an assembly procedure suffers from the disadvantage that it is carried out in an environment in which there may well be electrically live components, and therefore there is an associated safety risk. Also, the link box assembly cannot easily be tested.
  • pre-tailed link boxes are pre-assembled with short lengths of cable which are, in use, connected into the mains cable using straightforward mechanical connectors. Being factory- assembled, pre-tailed link boxes can be subject to stringent quality control and their installation carries much reduced safety risk.
  • Pre-tailed link boxes too are filled with resin, but a disadvantage of known forms of pre-tailed link box is that they comprise a number of discrete chambers, typically three such chambers. The "tails" are connected to terminals in the two outer chambers and are connected to spigots in the middle chamber, the spigots being used for connection of the links. Because the box is sub-divided into separate chambers, the insulating resin is present not as a unitary body but in several parts. There are therefore interfaces within the body of the link box which can have an adverse influence on the electrical properties of the box.
  • a pre-tailed link box comprising a housing within which one end of each of at least two cable tails is terminated, terminals to which the cable tails are connected being connected to spigots so as to form spigot assemblies across pairs of which removable links can be fitted so as to create connections between the cable tails, wherein the link box is formed as a unitary chamber.
  • the link box according to the invention is advantageous primarily in that since it is formed as a unitary chamber, when it is filled with insulating resin the resin forms a single block which surrounds and insulates the electrical connections with no interfaces or other discontinuities which might reduce or impair the electrical performance of the link box.
  • the housing of the link box is preferably formed in two halves, each of which is most preferably moulded in plastics material, eg by injection moulding, or vacuum forming.
  • the halves preferably cooperate to define openings for each cable tail and an enlarged central portion within which the appropriate electrical connections are accommodated.
  • the upper half of the housing is most preferably formed with one or more wells within which the spigots to which the cable tails are connected are accessibly mounted. Most preferably, separate and discrete wells are provided for each pair of spigots that, in use, are to be connected by links.
  • the dividing walls between wells are hollow and can be filled with resin during the resin casting process, effectively forming phase barriers.
  • the link box according to the invention may be manufactured particularly conveniently in an inverted position.
  • the cables are first terminated onto the spigot assemblies, preferably using a suitable jig, then mounted into the inverted upper half.
  • the lower half is then fitted on top and the housing is filled with resin.
  • a support, fitted below the upper half, preferably serves to limit the extent of the resin and is provided with recesses or the like to receive the tips of the spigots so that they project from the resin block once the resin has cured.
  • a method for the assembly of a link box having at least two cable tails and comprising an enclosure formed in upper and lower halves comprises the steps of a) positioning the upper half in an inverted condition upon a support which extends into link-receiving spaces in the upper half; b) connecting exposed ends of the cable tails to terminal assemblies having upstanding spigots; c) positioning said cable tails upon the inverted upper half such that the tips of said spigots are received within recesses in said support; d) positioning the lower half upon the upper half and connecting the upper and lower halves so as to form the enclosure; e) filing the enclosure with a resin; f) causing or allowing the resin to cure; and g) removing the enclosure from the support.
  • the support preferably is formed so as to close any openings in the upper half and so limits the upper extent of the resin block in the completed link box.
  • the support thus determines the depth of the wells.
  • the support preferably is formed with recesses or slots to receive the tips of the spigots. This ensures that the tips of the spigots are accessible in the finished link box and also facilitates accurate and precise positioning of the spigots during manufacture.
  • the lower half is most preferably provided with one or more fill openings.
  • the resin used may be any suitable resin, including those conventionally used for the filling of link boxes and other electrically insulating applications.
  • the link box may also contain a terminal for combined neutral and earth (CNE) conductors, which are commonly multi-stranded conductors that surround the live conductors of a three-phase cable, between those conductors and the outer insulation of the cable.
  • CNE neutral and earth
  • Figure 1 is an exploded view of a link box according to the invention
  • Figure 2 is an exploded view of a link spigot assembly forming part of the link box of
  • Figure 3 is an exploded view of a CNE take-off assembly forming part of the link box of Figure 1.
  • a link box according to the invention comprises a number of major components.
  • a lower shell half 6 is moulded in plastics material and cooperates with an upper shell half 4 to form an enclosure within which one end of each of two three-phase cable "tails" 5 is received.
  • the shell halves 4,6 are each generally hemi-cylindrical at their ends, the hemi-cylindrical end portions of the two halves 4,6 (when joined together) defining openings which closely surround the cable tails 5.
  • Each of the cable tails 5 comprises three solid cores 51 ,52,53 which are respectively provided with colour-coded red, yellow and blue insulation.
  • the cores 51 ,52,53 are of segmental cross-section, subtending angles of approximately 120°, so that the cores 51 ,52,53 fit together to form a circular cable.
  • Multi-stranded CNE conductors 54 surround the insulated cores 51 ,52,53 and are covered by an outer insulating sheath 55.
  • the spigot assembly 25 comprises a terminal spigot 10 which is fastened by means of a bolt 7 and interposed washer 8 and O-ring 9 to a terminal connector body 11.
  • the connector body 11 is generally of inverted U-shape, the downwardly depending limbs being formed with juxtaposed grooves 11a which serve to receive and retain an insert 12.
  • the insert 12 and connector body 11 together define a socket into which the exposed end of the respective core 51,52,53 can be inserted.
  • the insert 12 has a threaded bore 12a in which a shear head bolt 13 is engaged.
  • each core 51 ,52,53 is inserted into the socket of each spigot assembly 25 and the shear head bolt 13 tightened until its head shears off.
  • the bolt 13 thus clamps the end of the core 51,52,53 in the spigot assembly 25.
  • Spigot assemblies 25 are fitted in this manner to each of the three cores 51,52,53 of each of the two cable tails 5 (ie six spigot assemblies 25 in all). Fitting of the spigot assemblies 25 to the ends of the cores 51 ,52,53 may be facilitated by the use of an appropriate jig.
  • the upper shell half 4 is formed with three wells 41,42,43 which extend approximately one-half the depth of the upper shell half 4 and have hollow walls.
  • the upper shell half 4 is inverted and mounted upon a jig (not shown).
  • the jig extends into each of the three wells 41 ,42,43 and so defines the boundary of the resin which is filled into the link box as described below.
  • the assembly of cable tails 5 is then positioned (also inverted) upon the inverted upper shell half 4.
  • the cable cores 51 ,52,53 are arranged so that the cores of corresponding colour are aligned with the same well 41 ,42,43.
  • the upper surface of the upper shell half 4 is embossed, at the sides of the wells 41,42,43 with the letters R, Y and B to indicate red, yellow and blue.
  • the spigots 10 extend downwardly through the bases of the wells 41 ,42,43, the tips of the spigots 10 being received within recesses in the upper surfaces of those parts of the support that extend into the wells 41 ,42,43. This means that when the link box is filled with resin the tips of the spigots 10 will project from the resin into the wells 41 ,42,43.
  • the exposed strands of the CNE conductors 54 of each cable tail 5 are then drawn together and connected to a CNE take-off assembly 30, shown in more detail in Figure 3.
  • the CNE take-off assembly 30 comprises a connector body 14 of U- shape, the limbs of which are formed (in a similar manner to the limbs of the connector body 11 forming part of the spigot assembly 25) with grooves 14a in which an insert 15 is received.
  • the connector body 14 and insert 15 together define a socket into which the ends of the CNE conductors 54 can be inserted.
  • the insert 15 has a threaded bore in which an elongated fixing stud 20 is engaged, together with a washer 16 and nut 17.
  • the ends of the CNE conductors 54 of the two cable tails 5 are inserted into the socket in the CNE take-off assembly 30 and clamped in place by tightening of the stud 20.
  • the stud 20 has a shearable head 20a which breaks off.
  • the projecting end of the stud 20 is then passed through a hole 4b in the side of the upper half 4 and an upstanding spigot 18 is captivated on it (externally of the upper half 4) by a nut 19.
  • the lower shell half 6 is then placed over the inverted upper shell half 4 so that flanges 6a,4a on the two components abut.
  • the two shell halves 4,6 are then joined at the flanges 4a,6a by foam tape and sprung steel clips (not shown).
  • the completed enclosure defined by the shell halves 4,6 is then filled with an insulating resin by injection of the resin through fill holes 61 ,62 provided in the base of the lower shell half 6.
  • the entire interior volume of the link box is filled with a unitary block of insulating material which surrounds the cores 51 ,52,53, the spigot assemblies 20 and the CNE conductors 54 and CNE take-off assembly 30.
  • the link box is then ready for use and can be packaged together with a lid 1 and a set of link assemblies 2.
  • the lid 1 is cast in iron (or any other suitable heavy material) and is dimensioned to fit over the outer periphery of the wells 41 ,42,43.
  • the lid 1 has a considerable weight to ensure that it remains securely in place during use and is not lifted, eg by water in the event that the chamber within which the link box is fitted becoming flooded.
  • the link assemblies 2 comprise a pair of elongate plates, the bottom edges of which are flared outwards, the plates being resiliently biased together by clips 2a.
  • Colour-coded link gaskets 3, corresponding to the embossed letters R,Y,B, are fitted over the projecting tips of the spigots 10 in the bases of the wells 41 ,42,43.
  • the link box is installed and used in the manner of a conventional link box.
  • a typical installation will be in an underground chamber set into a roadway or other paved area.
  • the free ends of the cable tails 5 will be connected to three-phase mains supply cables using a standard cable-to-cable joint.
  • the CNE conductors 54 of the two cable tails 5 are connected via the neutral take-off assembly 30 embedded in the resin interior of the link box.
  • the other three cable cores 51 ,52,53 are connected only if link assemblies 2 are fitted in the respective wells 41 ,42,43 to form connections between the protruding tips of the spigot assemblies 20.
  • the lid 1 In normal use, the lid 1 is positioned over the wells 41 ,42,43. If it is desired to interrupt the flow of current along any particular core (red, yellow or blue) the lid 1 is removed and the corresponding link assembly 2 is removed from the appropriate well 41 ,42,43. To restore the flow of current, the link assembly 2 is replaced.

Landscapes

  • Connector Housings Or Holding Contact Members (AREA)
  • Auxiliary Devices For And Details Of Packaging Control (AREA)
  • Making Paper Articles (AREA)
  • Manufacturing Of Electrical Connectors (AREA)
  • Coupling Device And Connection With Printed Circuit (AREA)

Abstract

A pre-tailed link box comprises a housing within which one end of each of at least two cable tails (5) is terminated. The cable tails (5) connect to terminals connected to spigots (10) so as to form spigot assemblies (25). Removable links (2) can be fitted across pairs of spigots (10) so as to create connections between the cable tails (5). The link box is formed as a unitary chamber.

Description

Link Box and Method of Manufacturing the same
This invention relates to a so-called "link box", that is to say to a unit intended for installation in an electrical supply cable or cables so as to permit temporary interruption of current flow along that cable or cables.
Link boxes are widely used where it is desired temporarily to interrupt the supply of electric current in a cable or cables, typically a three-phase AC mains supply. Such boxes are commonly installed in underground chambers in roadways or other paved areas. In the simplest case, the link box is interposed between two parts of a cable and serves to either permit or interrupt the flow of current along the cable. In such a case, the link box contains two sets of terminals, for the individual cores of the two parts of the cable, and a set of mechanical links are used to connect the corresponding terminals to complete the current path. Physical removal of the link interrupts the flow of current. More complex arrangements are also possible in which a number of cables are connected to the link box and a variety of possible connections can be achieved by the use of appropriate links.
Originally, link boxes were connected to the supply cable in situ. By this is meant that a break was made in the cable, the ends of the cable cores were exposed and connected directly into the link box. After all the connections had been made, the link box was filled with a resin which surrounded and insulated the connections. Such an assembly procedure suffers from the disadvantage that it is carried out in an environment in which there may well be electrically live components, and therefore there is an associated safety risk. Also, the link box assembly cannot easily be tested.
For these reasons, it is known to use so-called "pre-tailed" link boxes. Such link boxes are pre-assembled with short lengths of cable which are, in use, connected into the mains cable using straightforward mechanical connectors. Being factory- assembled, pre-tailed link boxes can be subject to stringent quality control and their installation carries much reduced safety risk. Pre-tailed link boxes too are filled with resin, but a disadvantage of known forms of pre-tailed link box is that they comprise a number of discrete chambers, typically three such chambers. The "tails" are connected to terminals in the two outer chambers and are connected to spigots in the middle chamber, the spigots being used for connection of the links. Because the box is sub-divided into separate chambers, the insulating resin is present not as a unitary body but in several parts. There are therefore interfaces within the body of the link box which can have an adverse influence on the electrical properties of the box.
There has now been devised an improved form of link box, which overcomes or substantially mitigates the above-mentioned or other disadvantages of the prior art.
According to the invention, there is provided a pre-tailed link box comprising a housing within which one end of each of at least two cable tails is terminated, terminals to which the cable tails are connected being connected to spigots so as to form spigot assemblies across pairs of which removable links can be fitted so as to create connections between the cable tails, wherein the link box is formed as a unitary chamber.
The link box according to the invention is advantageous primarily in that since it is formed as a unitary chamber, when it is filled with insulating resin the resin forms a single block which surrounds and insulates the electrical connections with no interfaces or other discontinuities which might reduce or impair the electrical performance of the link box.
The housing of the link box is preferably formed in two halves, each of which is most preferably moulded in plastics material, eg by injection moulding, or vacuum forming. The halves preferably cooperate to define openings for each cable tail and an enlarged central portion within which the appropriate electrical connections are accommodated.
The upper half of the housing is most preferably formed with one or more wells within which the spigots to which the cable tails are connected are accessibly mounted. Most preferably, separate and discrete wells are provided for each pair of spigots that, in use, are to be connected by links. Preferably, the dividing walls between wells are hollow and can be filled with resin during the resin casting process, effectively forming phase barriers.
The link box according to the invention may be manufactured particularly conveniently in an inverted position. The cables are first terminated onto the spigot assemblies, preferably using a suitable jig, then mounted into the inverted upper half. The lower half is then fitted on top and the housing is filled with resin. A support, fitted below the upper half, preferably serves to limit the extent of the resin and is provided with recesses or the like to receive the tips of the spigots so that they project from the resin block once the resin has cured.
Thus, according to another aspect of the invention, there is provided a method for the assembly of a link box having at least two cable tails and comprising an enclosure formed in upper and lower halves, which method comprises the steps of a) positioning the upper half in an inverted condition upon a support which extends into link-receiving spaces in the upper half; b) connecting exposed ends of the cable tails to terminal assemblies having upstanding spigots; c) positioning said cable tails upon the inverted upper half such that the tips of said spigots are received within recesses in said support; d) positioning the lower half upon the upper half and connecting the upper and lower halves so as to form the enclosure; e) filing the enclosure with a resin; f) causing or allowing the resin to cure; and g) removing the enclosure from the support.
The support preferably is formed so as to close any openings in the upper half and so limits the upper extent of the resin block in the completed link box. Where the link box is formed with one or more wells in its upper surface, the support thus determines the depth of the wells. In such a case, the support preferably is formed with recesses or slots to receive the tips of the spigots. This ensures that the tips of the spigots are accessible in the finished link box and also facilitates accurate and precise positioning of the spigots during manufacture. To facilitate filling of the link box with resin, the lower half is most preferably provided with one or more fill openings. The resin used may be any suitable resin, including those conventionally used for the filling of link boxes and other electrically insulating applications.
The link box may also contain a terminal for combined neutral and earth (CNE) conductors, which are commonly multi-stranded conductors that surround the live conductors of a three-phase cable, between those conductors and the outer insulation of the cable. In some cases, for example with a four-core cable, it may be preferable to solidly connect one or more phases by passing a busbar through the link box rather than by providing a link and connecting arrangement for each individual phase.
The invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which
Figure 1 is an exploded view of a link box according to the invention;
Figure 2 is an exploded view of a link spigot assembly forming part of the link box of
Figure 1 ; and
Figure 3 is an exploded view of a CNE take-off assembly forming part of the link box of Figure 1.
Referring first to Figure 1 , a link box according to the invention comprises a number of major components. A lower shell half 6 is moulded in plastics material and cooperates with an upper shell half 4 to form an enclosure within which one end of each of two three-phase cable "tails" 5 is received. The shell halves 4,6 are each generally hemi-cylindrical at their ends, the hemi-cylindrical end portions of the two halves 4,6 (when joined together) defining openings which closely surround the cable tails 5.
Each of the cable tails 5 comprises three solid cores 51 ,52,53 which are respectively provided with colour-coded red, yellow and blue insulation. The cores 51 ,52,53 are of segmental cross-section, subtending angles of approximately 120°, so that the cores 51 ,52,53 fit together to form a circular cable. Multi-stranded CNE conductors 54 surround the insulated cores 51 ,52,53 and are covered by an outer insulating sheath 55.
At the end of each cable tail 5 which is received within the link box, the solid cores 51,52,53 are stripped of insulation so that they can be connected to spigot assemblies 25, one of which is shown in more detail in Figure 2. The spigot assembly 25 comprises a terminal spigot 10 which is fastened by means of a bolt 7 and interposed washer 8 and O-ring 9 to a terminal connector body 11. The connector body 11 is generally of inverted U-shape, the downwardly depending limbs being formed with juxtaposed grooves 11a which serve to receive and retain an insert 12. The insert 12 and connector body 11 together define a socket into which the exposed end of the respective core 51,52,53 can be inserted. The insert 12 has a threaded bore 12a in which a shear head bolt 13 is engaged.
In a first stage of assembly of the link box, the exposed end of each core 51 ,52,53 is inserted into the socket of each spigot assembly 25 and the shear head bolt 13 tightened until its head shears off. The bolt 13 thus clamps the end of the core 51,52,53 in the spigot assembly 25. Spigot assemblies 25 are fitted in this manner to each of the three cores 51,52,53 of each of the two cable tails 5 (ie six spigot assemblies 25 in all). Fitting of the spigot assemblies 25 to the ends of the cores 51 ,52,53 may be facilitated by the use of an appropriate jig.
Referring once again to Figure 1 , the upper shell half 4 is formed with three wells 41,42,43 which extend approximately one-half the depth of the upper shell half 4 and have hollow walls. To assemble the link box, the upper shell half 4 is inverted and mounted upon a jig (not shown). The jig extends into each of the three wells 41 ,42,43 and so defines the boundary of the resin which is filled into the link box as described below. The assembly of cable tails 5 is then positioned (also inverted) upon the inverted upper shell half 4. The cable cores 51 ,52,53 are arranged so that the cores of corresponding colour are aligned with the same well 41 ,42,43. The upper surface of the upper shell half 4 is embossed, at the sides of the wells 41,42,43 with the letters R, Y and B to indicate red, yellow and blue. The spigots 10 extend downwardly through the bases of the wells 41 ,42,43, the tips of the spigots 10 being received within recesses in the upper surfaces of those parts of the support that extend into the wells 41 ,42,43. This means that when the link box is filled with resin the tips of the spigots 10 will project from the resin into the wells 41 ,42,43.
The exposed strands of the CNE conductors 54 of each cable tail 5 are then drawn together and connected to a CNE take-off assembly 30, shown in more detail in Figure 3. The CNE take-off assembly 30 comprises a connector body 14 of U- shape, the limbs of which are formed (in a similar manner to the limbs of the connector body 11 forming part of the spigot assembly 25) with grooves 14a in which an insert 15 is received. The connector body 14 and insert 15 together define a socket into which the ends of the CNE conductors 54 can be inserted. The insert 15 has a threaded bore in which an elongated fixing stud 20 is engaged, together with a washer 16 and nut 17.
The ends of the CNE conductors 54 of the two cable tails 5 are inserted into the socket in the CNE take-off assembly 30 and clamped in place by tightening of the stud 20. The stud 20 has a shearable head 20a which breaks off. The projecting end of the stud 20 is then passed through a hole 4b in the side of the upper half 4 and an upstanding spigot 18 is captivated on it (externally of the upper half 4) by a nut 19. The lower shell half 6 is then placed over the inverted upper shell half 4 so that flanges 6a,4a on the two components abut. The two shell halves 4,6 are then joined at the flanges 4a,6a by foam tape and sprung steel clips (not shown).
The completed enclosure defined by the shell halves 4,6 is then filled with an insulating resin by injection of the resin through fill holes 61 ,62 provided in the base of the lower shell half 6. After curing of the resin the entire interior volume of the link box is filled with a unitary block of insulating material which surrounds the cores 51 ,52,53, the spigot assemblies 20 and the CNE conductors 54 and CNE take-off assembly 30. The link box is then ready for use and can be packaged together with a lid 1 and a set of link assemblies 2. The lid 1 is cast in iron (or any other suitable heavy material) and is dimensioned to fit over the outer periphery of the wells 41 ,42,43. The lid 1 has a considerable weight to ensure that it remains securely in place during use and is not lifted, eg by water in the event that the chamber within which the link box is fitted becoming flooded. The link assemblies 2 comprise a pair of elongate plates, the bottom edges of which are flared outwards, the plates being resiliently biased together by clips 2a. Colour-coded link gaskets 3, corresponding to the embossed letters R,Y,B, are fitted over the projecting tips of the spigots 10 in the bases of the wells 41 ,42,43.
The link box is installed and used in the manner of a conventional link box. A typical installation will be in an underground chamber set into a roadway or other paved area. The free ends of the cable tails 5 will be connected to three-phase mains supply cables using a standard cable-to-cable joint. The CNE conductors 54 of the two cable tails 5 are connected via the neutral take-off assembly 30 embedded in the resin interior of the link box. The other three cable cores 51 ,52,53 are connected only if link assemblies 2 are fitted in the respective wells 41 ,42,43 to form connections between the protruding tips of the spigot assemblies 20.
In normal use, the lid 1 is positioned over the wells 41 ,42,43. If it is desired to interrupt the flow of current along any particular core (red, yellow or blue) the lid 1 is removed and the corresponding link assembly 2 is removed from the appropriate well 41 ,42,43. To restore the flow of current, the link assembly 2 is replaced.

Claims

Claims
1. A pre-tailed link box comprising a housing within which one end of each of at least two cable tails (5) is terminated, terminals to which the cable tails (5) are connected being connected to spigots (10) so as to form spigot assemblies (25) across pairs of which removable links (2) can be fitted so as to create connections between the cable tails, wherein the link box is formed as a unitary chamber.
2. A link box as claimed in Claim 1 , wherein the housing of the link box is formed in two halves (4,6), each of which is moulded in plastics material.
3. A link box as claimed in Claim 2, wherein the halves (4,6) cooperate to define openings for each cable tail (5) and an enlarged central portion that accommodates the electrical connections.
4. A link box as claimed in Claim 2 or Claim 3, wherein the upper half (4) of the housing is formed with one or more wells (41 ,42,43) within which are mounted the spigots (10) to which the cable tails (5) are connected.
5. A link box as claimed in Claim 4, wherein separate and discrete wells (41 ,42,43) are provided for each pair of spigots (10).
6. A link box as claimed in Claim 5, wherein the dividing walls between wells (41 ,42,43) are hollow and can be filled with resin.
7. A link box as claimed in any preceding claim, wherein the housing is filled with resin.
8. A link box as claimed in Claim 7, wherein the tips of the spigots (10) project from the resin.
9. A link box as claimed in any preceding claim, which is provided with one or more fill openings (61 ,62) to facilitate filling of the link box with resin.
10. A link box as claimed in any preceding claim, wherein the housing contains a terminal (30) for combined neutral and earth conductors.
11. A method for the assembly of a link box having at least two cable tails (5) and comprising an enclosure formed in upper and lower halves (4,6), which method comprises the steps of a) positioning the upper half (4) in an inverted condition upon a support which extends into link-receiving spaces (41 ,42,43) in the upper half (4); b) connecting exposed ends of the cable tails (5) to terminal assemblies (25) having upstanding spigots (10); c) positioning said cable tails (5) upon the inverted upper half (4) such that the tips of said spigots (10) are received within recesses in said support; d) positioning the lower half (6) upon the upper half (4) and connecting the upper and lower halves (4,6) so as to form the enclosure; e) filing the enclosure with a resin; f) causing or allowing the resin to cure; and g) removing the enclosure from the support.
12. A method as claimed in Claim 11 , wherein the support is formed so as to close any openings in the upper half (4).
13. A method as claimed in any one of Claims 11 to 12, wherein the support is formed with recesses or slots to receive the tips of the spigots (10).
14. A method as claimed in any one of Claims 11 to 13, wherein the enclosure is filled with resin through one or more fill openings (61 ,62) in the lower half (6).
**************************************
EP01969928A 2000-10-06 2001-09-13 Link box and method of manufacturing the same Expired - Lifetime EP1323211B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GBGB0024479.8A GB0024479D0 (en) 2000-10-06 2000-10-06 Link box and method of manufacturing the same
GB0024479 2000-10-06
PCT/GB2001/004115 WO2002029932A1 (en) 2000-10-06 2001-09-13 Link box and method of manufacturing the same

Publications (2)

Publication Number Publication Date
EP1323211A1 true EP1323211A1 (en) 2003-07-02
EP1323211B1 EP1323211B1 (en) 2006-11-22

Family

ID=9900770

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01969928A Expired - Lifetime EP1323211B1 (en) 2000-10-06 2001-09-13 Link box and method of manufacturing the same

Country Status (7)

Country Link
EP (1) EP1323211B1 (en)
AT (1) ATE346396T1 (en)
AU (2) AU9005401A (en)
DE (1) DE60124749T2 (en)
GB (1) GB0024479D0 (en)
NZ (1) NZ524690A (en)
WO (1) WO2002029932A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3477786A4 (en) * 2016-06-30 2019-12-25 Xi'an Blue Diamond Electronic Technology Co., Ltd Wiring terminal facilitating identification of correct wiring

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2006200091B2 (en) * 2005-01-18 2009-03-12 Tyco Electronics Uk Limited Electrical link box
WO2009055847A1 (en) * 2007-10-29 2009-05-07 Tappat Engineering Pty Ltd Multi-way underground link box
GB2465813A (en) * 2008-12-01 2010-06-02 Rex Edward Michau A method and device for repairing and extending cables
GB2480872B (en) * 2010-06-04 2013-05-22 Prysmian Cables & Systems Ltd Link disconnecting box
US9147967B2 (en) 2012-09-11 2015-09-29 Tyco Electronics Canada Ulc Electrical connectors and methods for using same
US10498127B2 (en) 2017-09-26 2019-12-03 Te Connectivity Corporation Link box with removable cable entry seals
EP3651295B1 (en) * 2018-11-06 2022-05-11 Tyco Electronics UK Ltd Structural improvements of low voltage underground link boxes

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Publication number Priority date Publication date Assignee Title
US1640814A (en) * 1922-02-21 1927-08-30 Thomas E Murray Jr Distribution unit for electric circuits
CH469373A (en) * 1968-02-13 1969-02-28 Oskar Woertz Inh H & O Woertz Electrical terminal block with a detachably inserted isolating plug
DE4031556A1 (en) * 1990-10-05 1992-04-09 Metz Albert Blumberger Tel Connecting socket for electrical equipment - has bridging connector elements that provide interconnection between pairs of wires
FR2785457B1 (en) * 1998-10-30 2001-03-23 Thorn Europhane Sa CONNECTION DEVICE FOR LUMINAIRE

Non-Patent Citations (1)

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Title
See references of WO0229932A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3477786A4 (en) * 2016-06-30 2019-12-25 Xi'an Blue Diamond Electronic Technology Co., Ltd Wiring terminal facilitating identification of correct wiring

Also Published As

Publication number Publication date
EP1323211B1 (en) 2006-11-22
DE60124749T2 (en) 2007-10-04
GB0024479D0 (en) 2000-11-22
DE60124749D1 (en) 2007-01-04
NZ524690A (en) 2003-10-31
WO2002029932A1 (en) 2002-04-11
ATE346396T1 (en) 2006-12-15
AU2001290054B2 (en) 2005-02-17
AU9005401A (en) 2002-04-15

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