Patent Document

FIELD OF THE INVENTION  
         [0001]    This invention relates to a cable connection apparatus, in particular, cable connection apparatus suitable for connecting high current low voltage multi-core cables at a location where a switch or take-off connection is required.  
         BACKGROUND OF THE INVENTION  
         [0002]    The supply of electricity to domestic, commercial and industrial properties is achieved by installing a grid or network of high current carrying cables in an area where electrical connections are to be made. Preferably the creation of the network is undertaken during the establishment of a particular neighbourhood or facility, although of course recabling, and extensions of existing cabling, are often undertaken. Preferably all such cabling is buried under ground in specially constructed hollow pipes or service tunnels. Underground electrical services have one particular disadvantage and that is that the connection points of the cables, particularly at distribution points, can sometimes be submerged. For this reason considerable care has to be taken to ensure that water does not form a short circuit between different electrical cables or short circuit the supply to earth.  
           [0003]    Prior art installations have generally been extremely robust and bulky. Such systems have therefore been costly to install and have occupied significant space requiring large underground excavation and civil works. Prior art systems have also suffered from the disadvantage of being particularly time consuming to make all the necessary connections.  
           [0004]    Armoured electrical cables used to distribute power in domestic and commercial locations are frequently laid in trenches or conduits located relatively close to the surface. This provides for ready availability and accessibility of the cable, and also reduces the ground work which needs to be done in order to lay the cable.  
           [0005]    It is important that the connection of below ground electrical connections is protected against the ingress of moisture. In some underground locations there can be a problem of flooding of the excavation where the connection is located and therefor it is important that any exposed electrical conduits, particularly at the connection points, are properly protected against moisture contact.  
           [0006]    It is also important that the underground structure which is constructed to house a connection box is made as small as practicable in order to reduce the civil works necessary for installation. One problem with constructing a relatively small underground structure, particularly where the cables are laid relatively close to the surface, is that the cables tend to be externally armoured and have a relatively large minimum radius of curvature. Cables will tend to extend laterally to opposite sides of the underground structure, and then need to be curved or bent upwardly so that the end portions of the two cables are substantially vertical and parallel so as to be able to make the necessary connection. Since the cables have a large radius of curvature, and are relatively rigid, curving or bending the cables, and making the connection, and then fitting a water proof housing over the connection, becomes an arduous task, particularly when undertaken in the confines of a relatively small underground structure.  
         SUMMARY OF THE INVENTION  
         [0007]    It is an object of the present invention to provide for an improved form of electrical interconnection system.  
           [0008]    In accordance with a first aspect of the present invention, there is provided an electrical cable interconnection system for interconnecting the stripped ends of at least two multi-phase high current, low voltage input cables, the system including: a base portion for engaging the two input cables in a substantially horizontal manner; a connector block laterally displaced from the base portion and adapted to receive the ends of the input cables; a series of mating shell pieces together forming a water tight seal around the stripped ends of the input cables and the connector block.  
           [0009]    Preferably the system further includes, an insulating settable type material flowable into the cavity formed by the mating shell pieces, surrounding the stripped ends of the input cables.  
           [0010]    The connector block preferably can include a series of switch cavities formed therein, each of the cavities designed to receive a detachable switch unit for forming an electrical interconnection between corresponding ends of the input cables.  
           [0011]    The input cables are preferably engaged by the base portion in a first plane at a base of the system. The system can also include a bell housing for placing over the mating shell pieces for forming a diving bell type arrangement with the system.  
           [0012]    The connector block can preferably contain a series of pockets for placement of the detachable switch units when not in use. The series of cavities can include a designated neutral cavity of different dimensions to the other cavities.  
           [0013]    The system also preferably includes a moisture excluding dome for covering the connector block and series of resilient o-rings for placement around the outer surface of the input cables, the resilient o-rings engaging portions of the mating shell pieces so as to form a watertight seal between the input cables and the shell pieces.  
           [0014]    In accordance with a further aspect of the present invention there is provided an electrical connection and distribution system having a base member adapted to hold a pair of multi-phase electrical conduits in alignment with each other, a series of connector blocks for connecting together respective phase conduits, and distribution conduits adapted to be connected in use to said connection blocks for distributing electricity from the system.  
           [0015]    In the preferred form of the electrical connection and distribution system comprises:  
           [0016]    (a) a base member having at least a pair of conduit apertures therethrough, through which a pair multiphase electrical conduits pass in use, each multiphase electrical conduit being comprised of a plurality of phase conduits;  
           [0017]    (b) a plurality of connector blocks for connecting together respective phase conduits of said multiphase electrical conduits;  
           [0018]    (c) an upwardly open receptacle mountable to the base member adapted tosurround the conduits passing in use upwardly from the base member, and the connector blocks connected to such conduits, and adapted to receive and contain a settable material therein to form a fluid impervious solid body surrounding the conduits in use; and  
           [0019]    (d) an inverted generally dome or cup shaped moisture impervious shroud adapted to be fitted over the solid body to form a moisture resistant enclosure of the connected conduits.  
           [0020]    Preferably the base member includes one of more openings through which distribution lines to be distributed from the system can pass through the base member for connection to the connector blocks. The connector blocks preferably have respective connection facilities for connecting said distribution lines to said conduits.  
           [0021]    The connector blocks preferably comprise a body formed of a solid block of electrically conductive material having a series of apertures or slots therein for receiving conductors, and transverse threaded bores intersecting with the apertures for receiving clamping studs therein for clamping the conduits to the connector blocks. The clamping studs preferably include a rearward portion which is threaded and adapted to engage in the threads of the threaded bores, and a forward portion which is connected to the rearward portion via a frangible connection which permits the forward portion and rearward portions to shear relative to each other as the threaded studs is brought into operative engagement with a conduit located in the aperture. The forward portion may have a generally truncated conical configuration having a leading edge adapted to form a quality electrical connection with the conduit. The leading edge may be of sharpened configuration, or may be of rounded or knurled configuration to provide for said high quality connection.  
           [0022]    The system may further include at least one spacer member to hold the conduits in position relative to each other during the assembly of the system in use. A further feature of the invention is to provide for switching means between the connected phase conduits. In one form of the invention the switching mean is the only part of the system which is accessible after the solid body of settable material has been formed around the connected blocks. The switching means includes a removable bridge which is slidable into a passage formed in a switch housing, the switch housing being formed of electrically insulating material.  
           [0023]    Prior art installations have generally been extremely robust and bulky. Such systems have therefore been costly to install and have occupied significant space requiring large underground excavation and civil works. Prior art systems have also suffered from the disadvantage of being particularly time consuming to make all the necessary connections.  
           [0024]    In accordance with a further aspect of the present invention there is provided an electrical connection and distribution system having a base member adapted to hold a pair of multi-phase electrical conduits in alignment with each other, a series of connector blocks for connecting together respective phase conduits, and distribution conduits adapted to be connected in use to said connection blocks for distributing electricity from the system.  
           [0025]    In the preferred form of the invention the electrical connection and distribution system comprises:  
           [0026]    (a) a base member having at least a pair of conduit apertures therethrough, through which a pair multiphase electrical conduits pass in use, each multiphase electrical conduit being comprised of a plurality of phase conduits;  
           [0027]    (b) a plurality of connector blocks for connecting together respective phase conduits of said multiphase electrical conduits;  
           [0028]    (c) an upwardly open receptacle mountable to the base member adapted to surround the conduits passing in use upwardly from the base member, and the connector blocks connected to such conduits, and adapted to receive and contain a settable material therein to form a fluid impervious solid body surrounding the conduits in use; and  
           [0029]    (d) an inverted generally dome or cup shaped moisture impervious shroud adapted to be fitted over the solid body to form a moisture resistant enclosure for the connected conduits.  
           [0030]    Preferably the base member includes one of more openings through which distribution lines to be distributed from the system can pass through the base member for connection to the connector blocks. The connector blocks preferably have respective connection facilities for connecting said distribution lines to said conduits.  
           [0031]    The connector blocks preferably comprise a body formed of a solid block of electrically conductive material having a series of apertures or slots therein for receiving conductors, and transverse threaded bores intersecting with the apertures for receiving clamping studs therein for clamping the conduits to the connector blocks. The clamping studs preferably include a rearward portion which is threaded and adapted to engage in the threads of the threaded bores, and a forward portion which is connected to the rearward portion via a frangible connection which permits the forward portion and rearward portions to shear relative to each other as the threaded studs is brought into operative engagement with a conduit located in the aperture. The forward portion may have a generally truncated conical configuration having a leading edge adapted to form a quality electrical connection with the conduit. The leading edge may be of sharpened configuration, or may be of rounded or knurled configuration to provide for said high quality connection.  
           [0032]    The system may further include at least one spacer member to hold the conduits in position relative to each other during the assembly of the system in use. A further feature of the invention is to provide for switching means between the connected phase conduits. In one form of the invention the switching mean is the only part of the system which is accessible after the solid body of settable material has been formed around the connected blocks. The switching means includes a removable bridge which is slidable into a passage formed in a switch housing, the switch housing being formed of electrically insulating material.  
           [0033]    Further features of the invention will be made apparent from the description of two embodiments of the invention given below by way of example. It should be noted, however, that these specific features shown in the drawings should not be construed as limiting on the invention.  
           [0034]    According to a further aspect of the invention there is provided electrical cable connection apparatus for providing a water proof connection of at least two multi-core cables, said apparatus comprising:  
           [0035]    an open topped housing comprised of a plurality of shells adapted to be connected together around the connection of at least two cables, said housing comprising a generally cup shaped body adapted to encapsulate said connection and having a plurality of lower apertures in the base thereof, each lower aperture adapted to accommodate a cable to be connected, said shells each defining part of a said aperture for each of two cables to be connected together, the housing when assembled around a cable connection adapted to be at least partially filled with a settable material.  
           [0036]    According to a further aspect of the invention there is provided electrical cable connection apparatus for providing a water proof connection of at least two multi-core cables, said apparatus comprising:  
           [0037]    An open topped housing comprised of a plurality of shells adapted to be connected together around the connection of at least two cables, said housing comprising a generally cup shaped body adapted to encapsulate said connection and having a plurality of lower apertures in the base thereof, each lower aperture adapted to accommodate a cable to be connected, said shells each defining part of a said aperture for each of two cables to be connected together, said lower apertures each being aligned at an obtuse angle to the vertical, the housing when assembled around a cable connection adapted to be at least partially filled with a settable material.  
           [0038]    The shells are preferably moulded from a plastics material. Where the housing is adapted to encapsulate a connection comprised of two cables the shells are preferably identical. The angle of the apertures is preferably selected so as to accommodate the permissible angle of bending of the cables to be connected. The angle of the apertures may be at between 20° and 45° to the horizontal.  
           [0039]    According to a further aspect of the invention there is provided a bracket adapted to connect to and hold in relative alignment a pair of cables to enable the cables to be connected together. The bracket preferably comprises two cable gripping collars, each adapted to hold the pair of cables at an angle and in a position relative to each other to optimise the connection of the cables together. The bracket is preferably comprised of two mirror image parts, each part defining a respective half of the two cable gripping collars. The collars are preferably not coaxially aligned.  
           [0040]    The invention extends to a method of providing a moisture proof surround for a multi-core electrical cable connection, the method including the steps of:  
           [0041]    aligning two cables generally along an axis so that the cables extend laterally away from each other and the proximate ends of the cables overlap,  
           [0042]    stripping an outer protective sheath from both of the cables to expose the separate cores of the two cables;  
           [0043]    connecting the cores together;  
           [0044]    removing the bracket;  
           [0045]    fixing an open topped housing around the connection; and  
           [0046]    filling the housing with a settable material so as to encapsulate the connection within the settable material.  
           [0047]    The method may include the steps of covering the connection with a moisture excluding dome.  
           [0048]    Preferably, the system also includes a detachable switch unit including a series of conductive interconnection leads resiliently biased apart, the connection leads undergoing resilient compression upon insertion into the cavity when interconnecting with conductive portions of the connector block. The detachable switch unit can further include a detachable fuse interconnecting the conductive interconnection leads. Alternatively, the detachable switch unit can further include a distribution lead interconnected to at least one of the interconnection leads, the distribution lead for interconnection with a generator source for supplying electricity to the input cables.  
           [0049]    These and further features of the invention will be made apparent from the description of a preferred embodiment thereof given below by way of example. In the description references made to the accompanying drawings but the specific features shown in the drawings should not be construed as limiting on the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0050]    [0050]FIG. 1 shows a side view of an excavation at the location where two cables are to be connected;  
         [0051]    [0051]FIG. 2 shows the two cables secured together with a bracket;  
         [0052]    [0052]FIG. 3 shows a perspective view of two cables connected together with a bracket with one of the cables having its protective sheet stripped therefrom;  
         [0053]    [0053]FIG. 4 shows a side view of the two cables partially connected together;  
         [0054]    [0054]FIG. 5 shows a side view of the two cables connected together, still with the bracket in position;  
         [0055]    [0055]FIG. 6 shows a perspective view of the connected cables together with a housing for enclosing the connection;  
         [0056]    [0056]FIG. 7 shows a side view of the connection with the housing in operative position;  
         [0057]    [0057]FIG. 8 shows a side view with the housing in position and in which the housing is enclosed within a moisture excluding dome;  
         [0058]    [0058]FIG. 9 shows a side view of the connection in cross section view with the installation substantially completed;  
         [0059]    [0059]FIG. 10 shows a side view of the completed connection;  
         [0060]    [0060]FIG. 11 shows a plan view of the completed connection;  
         [0061]    [0061]FIG. 12 is an exposed perspective of an alternative embodiment;  
         [0062]    [0062]FIG. 13 illustrates a portion of the arrangement of FIG. 12;  
         [0063]    [0063]FIG. 14 is a sectional view through an assembled form of the second embodiment;  
         [0064]    [0064]FIG. 15 is a sectional view through a portion of the second embodiment  
         [0065]    [0065]FIG. 16 shows a perspective view of a further embodiment of the invention with the conduits in an assembled condition.  
         [0066]    [0066]FIG. 17 shows that plan due of a base member used in the assembly of FIG. 16 with the conduits in position.  
         [0067]    [0067]FIG. 18 shows a side view of the base member shown in FIG. 17 with the conduits in position.  
         [0068]    [0068]FIG. 19 shows a plan view of the connector blocks for the system shown in FIG. 16 in the assembled condition.  
         [0069]    [0069]FIG. 20 shows an exploded perspective view of a connector block for the system shown in FIG. 16.  
         [0070]    [0070]FIG. 21 shows a side view of the threaded stud used for mounting conduits to the connector block shown in FIG. 20.  
         [0071]    [0071]FIG. 22 shows a sectional view of the stud shown in FIG. 21.  
         [0072]    [0072]FIG. 23 shows perspective view of the system in which the conduits are encapsulated within a resin material.  
         [0073]    [0073]FIG. 24 shows a perspective view of a second further embodiment of the invention with conduits connected to switched connector blocks.  
         [0074]    [0074]FIG. 25 shows an exploded perspective view of a switched connector block.  
         [0075]    [0075]FIG. 26 shows a perspective view of three switched connector blocks with one of the removable bridges removed from its connector block.  
         [0076]    [0076]FIG. 27 shows a plan view of three connector blocks aligned side by side.  
         [0077]    [0077]FIG. 28 shows a sectional view along line XII-XII depicted in FIG. 27.  
         [0078]    [0078]FIG. 29 shows a perspective view of the system shown in FIG. 24 with the conduits encapsulated in a settable resin material.  
         [0079]    [0079]FIG. 30 is an exploded perspective view of a portion a further alternative embodiment.  
         [0080]    [0080]FIG. 31 is a perspective view illustrating the assembly process of the further alternative embodiments.  
         [0081]    [0081]FIG. 32 is a further perspective view of the assembly process of the further embodiment.  
         [0082]    [0082]FIG. 33 illustrates the assembled form of the further alternative embodiment.  
         [0083]    [0083]FIG. 34 in an exploded perspective of a fuse switch.  
         [0084]    [0084]FIG. 35 illustrates a generated distribution link switch utilise with the preferred embodiment.  
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0085]    As shown in the drawings two cables, numbered  10  and  12 , are connected together within an excavation  14  so that the connection of the cables is below ground level  16 . It is important that the excavation  14  is kept to a relatively small size so that the civil work associated with completing the connection is kept to a relatively small scale.  
         [0086]    The cables  10  and  12  will extend laterally to opposite sides of the excavation  14 , the cables  10  and  12  being laid substantially horizontally but relatively close to the ground surface  16 . In a typical arrangement the cables  10  and  12  might be between about 400 mm and 1000 mm below the ground surface  16 .  
         [0087]    Multi-core cables of the type with which the embodiment is adapted to be used are relatively rigid and typically have an armoured multi-strand earth and waterproof outer sheath which significantly increases the rigidity of the cable. The cables as shown in FIG. 1 have been bent to substantially their minimum radius of curvature within the excavation  14  but in that position the ends  18  of the two cables are still relatively far apart.  
         [0088]    To facilitate the connecting together of the cores of the two cables  10  and  12 , a bracket  20  is fitted to the two cables as shown clearly in FIG. 2 of the drawings. The bracket  20  comprises a pair of cable gripping collars  22  connected together by a rigid arm  24 . The bracket  20  is formed of two identical halves which are bolted together around the cables as shown by fasteners  26 . When the bracket is in position as shown in FIG. 2, the two cables  10  and  12  will be held together rigidly and in the optimal alignment relative to each other for completing the connection. It will be appreciated that fitting the bracket  20  in position will be reasonably easy to achieve, although the cables are relatively rigid, since they will still be able to be manipulated and bent by workers operating from outside the excavation  14 .  
         [0089]    As shown in FIG. 3, the outer sheath  28  of the cable  10  has been cut away from the cores  30  and the armoured earth sheath  32 . Each of the cores  30  has an insulating sheath  34  surrounding the conductor  36  which is stripped away shown in FIG. 3 to allow for the connection of those cores together in the manner described below. It will be appreciated from FIG. 3 that with the bracket  20  in position the two cables  10  and  12  are held facing each other at an optimal angle, given the practical limitation on curvature of the cables to thereby allow the two sets of cores  30  to be connected together whilst the cables  10  and  12  are held in their optimal relative positions.  
         [0090]    [0090]FIG. 4 depicts the arrangement when the sheath  28  has been cut from both cables  10  and  12  and the ends of the cores  30  have been stripped of their protective sheaths to facilitate connection. In addition, the multi-strand earth cables  32  have been connected together by means of a bolt and nut assembly  38 , and the bracket  20  still holds the two cables  10  and  12  relative to each other.  
         [0091]    [0091]FIG. 5 depicts a switch connection block  40  mounted to the ends of the cores  30 . The switch connection block has three upper switch housings  42  adapted to receive switching means (not shown) to either connect or disconnect the connection between respective cores in use. The switch connector block  40  is shown in more detail in FIG. 6 of the drawings from which it is clear that each pair of cores  30  can be individually switched, with a separate switch being located in each of the respective housings  42 .  
         [0092]    Once the switch connector block is in position and the nut and bolt assembly  38  ties the earth cables together, the connection will be relatively rigid and the bracket  20  can be removed from the cables  10  and  12 . Because the connection, at this point, is relatively rigid, the cables will not tend to move apart or change their orientation relative to each other. Thus, a housing  44  can be fitted around the connection.  
         [0093]    The housing  44  is comprised of two substantially identical shells  46  which are adapted to be bolted together around the connection. The housing  44 , when assembled, defines a pair of lower apertures  48  which are adapted to locate around and seal with the outer surface of the cables  10  and  12 . The apertures  48  include an O-ring type seal which locates in grooves  50  located within the inside of the apertures  48 . The shells  46  include flanges  52  in which a series of holes  54  are located for receiving nut and bolt assemblies for bolting the two shells together around the connection, thereby defining an open topped housing which is sealed to the cables  10  and  12  and is sealed at the interface between the two shells. If necessary, sealing means such as an adhesive may be placed at the interface between the two shells to ensure a waterproof seal at that interface.  
         [0094]    As will be clear from FIG. 7 of the drawings, when the two shells are bolted together the switch housings  42  of the connection extends out of the open upper end  36  of the housing  44  since in use it is necessary to have access to the switch housings  42 . When the shells are bolted together a resin, or other suitable non-electrically conductive settable material, can be poured into the open top  56  of the housing  44  to fully encapsulate the connection in that resin material. This will have the effect of excluding moisture from the connection, even where the connection lies in water, as occurs from time to time in underground installations.  
         [0095]    A further water exclusion device comprising an inverted cylindrically shaped air tight dome  58  is placed over the housing  44 , the dome  58  being used to exclude moisture from the connection, even in situations where the connection is fully immersed in water. Furthermore, as shown in FIG. 8, the excavation can at this stage be completed. A sand, or similar material has been filled into the bottom of the excavation  14  the sand  16  forming a pervious base for the excavation and providing added support for the cables.  
         [0096]    As shown in FIG. 9, a cylindrical permanent outer housing in the form of a shutter  62  will then be placed in the excavation so as to stand on the upper surface of the sand layer  60  as shown. The upper edge  64  of the cylindrical shutter is flush with the ground level  16 . A concrete mix  66  may then be filled into the annular space between the excavation  14  and the shutter  62  which rigidly secures the shutter  62  in position within the excavation  14 . A cap  68  is secured to the shutter  62  by means of screws  70 , the cap  68  serving to hold the dome  48  in position. Preferably the inner wall of the shutter  62  has a detent  72  projecting inwardly towards the dome  58  and the dome  58  includes notches  74  with which the detent  72  engages in order to hold the dome  58  in position, even where water  76  has entered into the annular space between the dome  58  and the shutter  62 . In practice, where it is desired to inspect the connection or operate the switches, the lid  68  will be removed and the water  76  will be pumped or suctioned out of the annular space between the dome  58  and the shutter  62  to ensure that the dome does not float upwardly, thereby exposing the connection to immersion by the water  76 .  
         [0097]    [0097]FIG. 10 depicts the assembly in its fully completed condition and FIG. 11 depicts the assembly, in plan view, with the cables  10  and  12  extending laterally to opposite sides of the connection.  
         [0098]    It will be appreciated that the invention is not limited to the form of assembly depicted in the drawings. For example, where the cable is to be connected have a lesser or greater curvature the angles of the apertures  48  might differ from those described herein. In addition, the form of the housing  44  may differ for different forms of connection arrangements. Where more than two cables are to be connected together, clearly there will need to be a different arrangement of housing so that if three cables were to be connected together there might need to be a housing comprised of three substantially identical shells.  
         [0099]    Alternative arrangements are possible. One such alternative arrangement will now be described with reference to FIG. 12 to FIG. 15.  
         [0100]    In FIG. 12, there is shown a modified embodiment  80  which allows for horizontal cables to enter the casing arrangement. This can be seen clearly from FIG. 14 which shows a sectional view through an assembled arrangement. In FIG. 12, the neutral lines  81  and positive phases e.g.  82  are bent after exiting of the combined section cable  83 . The neutral cable is drawn together and passed through an aperture within bolt  85  which is interconnected to a bracket  86 . This allows for independent interconnection of the neutral line and testing thereof.  
         [0101]    Turning to FIG. 13, the sector cables (not shown) are interconnected with a mating conductive plate  90  by means of clamping units  91 ,  92  and clamping bolts  93 ,  94 . The clamping bolts  93 ,  94  include shear bolt ends which shear and compress the sector cable upon insertion. This can be seen in FIG. 15 which illustrates a sectional view through the to connector box. The connector box is separated by an insulating plate  97  during operation. FIG. 14 illustrates the assembled form of the arrangement which also includes a bell cover  98 . The arrangement of FIG. 14 providing the benefits that cables  99  and  100  enter the arrangement in a horizontal manner.  
         [0102]    Further altenative arrangements are possible. Depending on requirements different forms of sector cables may be present. For example, in some environments  4  core sector cables may be used rather than  3  core wave cable. Further it may be desirable to tape off a distribution feed from the main sector cable.  
         [0103]    An alternative distribution system will now be described. Referring initially to FIGS.  16  to  24 , an electrical connection and distribution system  110  provides a relatively simple arrangement for connecting together two multiphase conduits, numbered  112  and  114 , and allowing a distribution conduit or conduits  116  to be connected at this connection point. FIGS.  16  to  23  show a single distribution cable  116  but clearly it will be possible to have a plurality of distribution cables  116  should this be desirable. The system  110  shown in the drawings is suitable for use distributing electricity in an urban electricity distribution network and in the embodiment shown the conduits  112  and  114  have four “phase conduits”  118  which are to be connected together. That is to say, the conduits  112  and  114  are electrically connected to each other via the system  110 .  
         [0104]    The conduits  112  and  114  are each bent through 90° at the point of connection and pass upwardly through a base member  120  which is formed in two halves  122 A and  122 B which are mirror images of each other and are held together by nut and bolt assemblies  124 . The assembled base member  120  defines a pair of parallel apertures  126  and the conduits  112  and  114  pass through a respective one of those apertures  126  as shown. Typically the base member  120  will be assembled around the two aligned conduits, the external sheathing  128  will then be removed from the conduits above the base number to expose the phase conduits  118  extending upwardly from the base member  120 . At this point a clamping and spacer member  130  can be fitted to the phase conduits  118  to hold the phase conduits  118  in their correct positions relative to each other to thereby allowing connector blocks  132  to be mounted to the exposed upper ends of the phase conduits  118 . As shown in FIG. 16, since there are four phase conduits  118  in each conduit  112 ,  114  there will be four connector blocks  132  to provide the necessary connections. The connector blocks  132  are described in more detail below.  
         [0105]    Extending upwardly from the connector blocks are respective testing conduits  134  which are capped with insulated caps  136 , the testing conduits  134  being used for testing purposes in the event of a breakdown in the electrical distribution network.  
         [0106]    The distribution conduit  116  is also four phase conduit and the individual distribution phase conduits  138  connect to respective connector blocks  132  in a manner described in more detail below.  
         [0107]    The manner in which the conduits  112  and  114  pass through the base member  120  is shown in more detail in FIGS. 17 and 18 of the drawings. A suitable mastic material can be used to ensure that moisture proof seal is achieved at the apertures  26  where the conduits pass through the base member. It will be noted that the base member has a pair of side openings  140  to allow for distribution cables  116  to pass from the connector blocks to the point of power utilisation.  
         [0108]    Once the phase conduits  118  and the distribution conduits  116  have been connected to the connector blocks  132  all of the conduits will be encapsulated within an upwardly open receptacle  142 , best shown in FIG. 23 of the drawings. The receptacle  142  is formed in two parts,  144 A and  144 B, which are held together by clips  146 . The lower portion  148  of the receptacle  142  is configured to engage with a lip  150  defined around the periphery of the base member  120 . Thus, the lower portion  48  of the receptacle  142  fits inside that lip  150  in neat sliding fit, the lip  150  assisting to hold the receptacle  142  in a assembled configuration. A mastic material can be used to seal the receptacle to the base  120 . Once the receptacle  142  is in position, a settable electrically insulating material such as a resin material  152  is poured into the open top of the receptacle  142  to completely encapsulate all of the conductors and the connector blocks  132 . It is only the testing conductors  134  which project upwardly out of the resin material  152  to allow for the aforementioned testing procedures. It is envisaged that the resin material  152 , once set, will have the effect of excluding moisture from the entering and interfering with the operation of the system. It is also envisaged that a dome shaped cover will be fitted over the receptacle  142 , in the manner shown in FIG. 29 of the drawings, the cover performing in the manner of a “diving bell” to ensure the exclusion of water from the distribution system, even in situations where the assembly is submerged under water as occurs from time to time in underground insulations.  
         [0109]    As shown in FIG. 20 of the drawings, the connector blocks  132  are formed of solid blocks of metal, typically brass, and have two v-shaped grooves or slots  154  formed therein adapted to receive the phase conduits  118  therein. Once the conduits are in position in the grooves  154  a closure plate  156  is inserted into position between guides  158 , the closure plates  156  having threaded bores  160  passing there through into which threaded studs  162  are screwed, the studs  162  being adapted to press against the conduits located in the grooves  154  to clamp the conduits to the connector blocks  132 .  
         [0110]    The threaded studs  162  are shown in more detail in FIGS. 21 and 22. It will be noted that the studs include a rearward threaded portion  164  and forward engagement portion  166 , the two portions being connected together by a frangible neck  168 . The leading end of the forward portion  170  is sharp and will tend to dig into the conduit located in the groove  154 . Further tightening of the studs  162  will have the effect of shearing the neck  168 . The net result of this arrangement is that a forward and rearward portions of the studs  162  will form a face to face contact with each other and the leading end  170  of the stud will be, at least to some extent, embedded in the conduit. Oxidation of the conduit will not reduce the quality of the contact between the stud and the conduit.  
         [0111]    Turning now to FIGS.  24  to  29  of the drawings a further embodiment is shown which is similar to that of the previous embodiment except that this embodiment includes a switching arrangement.  
         [0112]    As shown, two multiphase conduits  212  and  214  pass through a base member  220  and the outer sheathing of the conduits is stripped off the phase conduits  218  and the phase conduits are connected to connector blocks  232 . In this embodiment, however, the multiphase conduits have an outer sheath of  219  conductor strands which form a neutral or earth line for the conduits  212  and  214 . The outer conductor sheaths  219  connect to a connector block  233  which in turn has a testing conduit  134  mounted thereto. Distribution conduits  216  are connected to the connector blocks  232  and  233 .  
         [0113]    It will be noted that the connector blocks  232  are formed in two halves marked as  232 A and  232 B. These two halves in each case are connected together by switching device  272  which is shown in detail in FIGS.  25  to  28  of the drawings. The switching device  272  includes a rectangular housing  274 , formed of a electrically insulated material, having a rectangular passageway  276  in the upper side thereof. The two connector blocks  232 A and  232 B each have a pair of conductor studs  278  mounted thereto, and the two connector blocks  232 A and  232 B are held together and in alignment with each other by a spacer device  280 . The studs  278  pass into the interior of the housing  274  and can be electrically connected together by a bridge device  282  which is slidable into the passageway  276 . The bridge device  282  has a handle  284  which, when the bridge device  282  is fully inserted into the passageway  276  the handle  284  will be twisted to rotate a cam (not shown) which causes a pair of conductors  286  to move apart into electrical contact with the studs  278 . Thus, when the bridge device  282  is removed from the passageway  276  there will be no electrical contact between the two connector blocks  232 A and  232 B.  
         [0114]    The distribution conductors  238  will be connected to the conductor blocks  232 A and  232 B by means of threaded studs  288 .  
         [0115]    Once the conductors have all been connected to the conductor blocks  232 A and  232 B, a receptacle  242  will be fitted around the conductors as shown in FIG. 29 and in much the same manner as described previously with reference to FIG. 23. A suitable resin material  252  will then be poured into the receptacle  242  to encapsulate the conduits, thereby preventing the ingress of moisture into the assembly in underground locations. A dome shaped housing  290  may then be located around the outside of the receptacle  242  and tied into position using straps  292 . The housing  290  will act in the manner of a diving bell to prevent water coming into contact with the connector blocks, even in situations where the entire installation is submerged under water as may happen from time to time in underground installations.  
         [0116]    It will be noted that when the resin material  252  has been poured into the receptacle  242  the switch mechanisms  272  remain above the upper surface of the resin material  252 . Thus, at any time, the switches may be either open or closed, depending upon the requirements of the network. It will be appreciated that even with the housing  290  removed, there is no exposed live contact surface which a maintenance worker could inadvertently touch during maintenance operations. Thus, it will be possible to switch the assemblies even when power remains connected to the installation in use.  
         [0117]    Turning now to FIG. 30, there is illustrated a further alternative embodiment.  300 . This embodiment is designed to interconnect two wave core sector cables  301 ,  302 . The outer covering of the sector cable is removed and the ends of each sector cable eg.  304  which, in this case, are assumed to be formed from aluminium, are formed as illustrated  304 . A rubberised sleeve  305  is placed around each end of the cable  301 ,  302 . The cable  301 ,  302  is placed within a base member  307  and affixed thereto by means of clamping units  309  which utilise a series of screws and bolts  311 ,  312 .  
         [0118]    Turning now to FIG. 31, the sector cables are then bolted to a top connecting unit  312 . The connecting unit is similar to the unit depicted in FIG. 24 however, the number of simplifications have been made thereto as a result of the pre treatment of the end  304  of each of the phase cables  306 . Due to the end treatment of the ends of the said cable  304  a simplified form of screw bolt  314  can be utilised. Additionally, connecting unit at  312  contains a series of storage cavities eg  315  for storage of switches when not in use. These switches are designed to be inserted in cavities eg  316  as previously discussed. Additionally, a neutral cavity  317  is provided preferably of different dimensions to the three phased cavities eg  316 . The neutral cavity  317  interconnecting neutral wires eg  310 .  
         [0119]    Two outer shell pieces, one of which is shown in FIG. 31 are provided for encasing the arrangement. In FIG. 32, there is illustrated the outer shells in an assembled form. The outer shells include scalloped edged portions  320  and are joined together by a series of screw and nut arrangements eg  321 . The casing  319  provides a waterproof sealing of the sector cable interconnection. The internal portions of the casing  319  can then be filled with an insulating resinous material which sets so as to provide for a fully insulated interconnect  
         [0120]    Whilst FIG. 26 illustrated a bridge or link switch for insertion into a corresponding cavity, FIG. 32 illustrates a series of fuse arrangements eg  323 , the details which are described hereinafter with reference to FIG. 34.  
         [0121]    The outer portion of the casing  319  includes a stage  325  for connecting a rods  326 . The rods  326  are utilised to couple a dome  330  as illustrated in FIG. 33 utilising wing nuts eg  371 . The dome  330  is again utilised to provide for a diving bell type effect wherein when a chamber containing the interconnection arrangement is flooded, an air gap is formed providing protection against ingress of water.  
         [0122]    Turning now to FIG. 34, there is illustrated one form of fuse switch  323 . The fuse switch includes a fuse  341  which is interconnected to a base plate leaf portion  342  by screw  343  and bolt  344 . The leaf portion  342  is in turn interconnected to conductive plates eg  346 ,  347  which are formed within a resilient compound  349  which can comprise a rubber or a polymer with similar rubber like resilient properties. The rubber  349  is designed to resiliently expand the two plates  346 ,  347  such that when the fuse  323  is placed within a mating cavity (eg  316  of FIG.  31 ) the plates  346 ,  347  and rubber  349  undergo a resilient compression form a strong contract with corresponding mating services. A plastic cover  350  is also provided for detachable mounting over the fuse  341  by means of screws eg  352 .  
         [0123]    Often, the situation may arise where a transformer interconnecting a sectored cable arrangement fails. Hence, there may be an urgent need to supply electricity via a sector cable arrangement. The interconnection system of the preferred embodiment provides for the opportunity for rapid supply of electricity from a generator source. The arrangement of FIG. 34 can be adapted as shown in FIG. 35 so as to provide for a generator power source. The adaption is provided so that a cable  354  is inserted through the plastic covering  355  which includes an arrow  356  showing the direction the distribution unit  357  should be inserted. The cable  354  is interconnected to the conductive leaf  359  by means of bolt and nut arrangement  361 ,  362 . The unit  357  can be rapidly deployed when a generator power source is required. By opening the top of the supply unit and changing any inserted bridge switch or fuse switch to a generator source, power can be rapidly supplied to one or more of the sector cables.  
         [0124]    It will be evident that the embodiments have a number of advantages. These include the high tolerance bell housing allowing for full submersion of the switch. Further, the rubber moulding arrangement illustrated in FIG. 34 provides an alternative form of link switch arrangement. The system is touch safe which provides for a safer working environment. The slots e.g.  315  of FIG. 31 provide for a place to spare links and keys when not used. Further, the arrangement of FIG. 32 provides for a neutral housing.  
         [0125]    It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.  
         [0126]    The foregoing describes embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto, without departing from the scope of the present invention.

Technology Category: 5