AU2004234962B2 - Electrical termination system - Google Patents

Description

- 1 TITLE: ELECTRICAL TERMINATION SYSTEM FIELD OF THE INVENTION The present invention relates to the field of high current low voltage cable interconnections and, in particular, discloses a compact arrangement for interconnecting 5 such cables. BACKGROUND OF THE INVENTION Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. 10 For interconnecting high current, low voltage cables, such as sector cables, systems presently in use in Australia are primarily based around a lug interconnection system. In these systems, a lug is initially place over one end of a sector cable. The lug is then crimped to the end of the cable using a hydraulic crimping device. To interconnect two sector cables, a bus bar is passed between the two lugs. This is often followed by the 15 placing of a heat shrunk sealing cover over the interconnection so as to provide for a form of insulation. This process can be unduly complex and requires expensive and temperamental crimping equipment in addition to the utilisation of heat shrinking materials that can provide a significant fire hazard. 20 Electrical distribution systems are obviously an essential and critical requirement in modern society. Often, electricity is distributed along a main line down a street and various minor tap-off wires are taken from the main line to be distributed to houses or factories or the like. The distribution normally occurs along high current low voltage lines that can typically be excessive bulky.

-2 Often there is a need to terminate 1, 2 or 3 of these lines whilst still providing tap off capability in the termination. Different forms of prior art termination can be utilised. There is a general need for an inexpensive termination system that can be rapidly mounted to terminate sector cables. 5 SUMMARY OF THE INVENTION It is an object of the present invention, in its preferred form, to provide for an alternative system of interconnecting or terminating cables. In accordance with a first aspect of the present invention, there is provided a cable termination and interconnection system comprising: 10 a conductive unit for conductively clamping around a sector cable; at least one tapoff hole formed within said conductive unit for insertion of at least one conductive electrical tapoff cable ; and interconnecting means for conductively interconnecting at least a first and second conductive unit so as to provide electrical interconnection between at least a first and 15 second sector cable. The tapoff holes can include secondary holes of insertion of engagement screws for engaging the tapoff cables in the tapoff holes. The system further preferably can include a nonconductive cover including apertures for the insertion of sector cables there through. The detachable conductive unit can include a conductive protrusion projecting 20 through the non-conductive cover, the conductive protrusion including engagement means for engaging with other cable termination systems so as to provide for interconnection between sector cables. In accordance with a further aspect of the present invention, there is provided a system for interconnecting conductive units of the type defined above wherein the - 3 interconnection system can comprise a conductive block engaging two profiled surfaces on the conductive units in a detachable interconnection. In accordance with a further aspect of the present invention, there is provided a system for interconnecting at least a first and second sector cable comprising: first and 5 second clamping unit for conductively clamping around an end of the first and second sector cable respectively utilising a reversible clamping mechanism, each of the first and second clamping unit including an external protrusion; and a conductive interconnect for reversibly clamping the external protrusions together. In accordance with a further aspect of the present invention, there is provided a 10 compact arrangement for interconnecting together at least 3 sector cables, the arrangement including: a first connector block for conductively interconnecting first and second sector cables, with a first end of the first sector cable protruding through the first connector block; a second connector block conductively interconnected to the first end and a third sector cable. 15 The first and second connector blocks are preferably formed substantially from a conductive core surrounded by an insulating cover. At least one of the sector cables can be interconnected to a predetermined first connector by means of a releasable clamping element. The releasable clamping element preferably can include a screw engaging a thread in a plate for urging the sector cable against a surface of the corresponding 20 connector block. Each of the conductor blocks preferably can include a conductive portion including a series of secondary clamping units for clamping a series of tap off cables, having lower current carrying capacity than the sector cables, to the conductive block. In accordance with a further aspect of the present invention, there is provided an 25 arrangement for interconnecting at least two sector cables, the arrangement comprising: -4 an inner conductive core including at least two apertures having a clamping arrangement formed around the apertures; an outer insulating mould including at least two apertures substantially coaxial with the inner conductive core apertures, for receipt of the sector cables. 5 The outer insulating mould further can comprise at least two apertures aligned with first portions of the inner conductive core, the first portions including clamping elements for clamping the sector cables to the conductive core, the clamping elements being operable through the two apertures. The system can also include a base plate having a alignment structure formed on 10 the surface thereof, the base plate utilised in practice to align the sector cables in a predetermined relationship with the connector blocks. In accordance with a further aspect of the present invention there is provided a cable termination system including: a first cable engaging unit having a profiled aperture formed therein, said profile being substantially of a form suitable for engaging the cross 15 section of a predetermined cable; a screw detachable conductive unit including a mating surface for mating with the first cable engaging unit and an urging means for clamping the sector cable against the walls of said aperture; and a series of tapoff holes formed within the screw detachable conductive unit for insertion of conductive electrical tapoff cables of a smaller diameter than the sector cable. Preferably, the first cable engaging 20 unit is formed from an extruded section as is the said screw detachable conductive unit. Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

- 4a BRIEF DESCRIPTION OF THE DRAWINGS Preferred forms of the present invention will now be described with reference to the accompanying drawings in which: Fig. I is a side perspective view of a four-way termination with side tap-off of an 5 electrical supply; Fig. 2 is a side perspective view of one of the termination units of Fig. 1; Fig. 3 is a sectional view through the line A-A' of Fig. 2; Fig. 4 is and exploded side perspective view of a portion of the termination unit of Fig. 1.

WO 2004/098008 PCT/AU2004/000543 -5 Fig. 5 illustrates a side perspective view of an alternative embodiment; Fig. 6 is a side perspective view of the conductive portions of the arrangement of Fig. 5; Fig. 7 is a sectional view through the arrangement of Fig. 5; 5 Fig. 8 is a side perspective view of a further alternative embodiment; Fig. 9 is a sectional view through the arrangement of Fig. 8; Fig. 10 is a side perspective view of a neutral termination; and Fig. 11 is a side perspective view of a single sector cable termination. 10 DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS In the preferred embodiments there is provided a method for conveniently and rapidly interconnecting and terminating electrical cables associated with an electrical distribution systems. Various systems are illustrated including a two way termination. Turning initially to Fig. 1, there is shown 1 an initial four way termination or 15 interconnection of two four core underground sector cables 2,3. Each of the four core sector cables has 4 separate sector cables e.g. 4, with generally three phases and a neutral being provided. Whilst the present embodiment is described in relation thereto, it will be obvious to those skilled in the art that it is not restricted thereto. It is assumed the underground sector cables 2, 3 are fed from the underground through a base mounting 20 plate 6 with the arrangement 1 ideally fitting with a small container shell (not shown) designed to mate with the base plate 6. A series of termination units e.g. 5 is provided with each termination unit interconnecting two matched sector cables and providing for power supply tap-off to household power lines via tap-off cables e.g. 8.

WO 2004/098008 PCT/AU2004/000543 -6 Fig. 2 illustrates a single termination unit 5 in more detail. Each termination unit 5 includes an insulating cap 10 which is screw fixed to two termination blocks units 11, 12. The cap 10 is designed to fit over and insulate a connection block Out of each insulating cover 11, 12 protrudes a conductive arm 17,18. The two 5 conductive arms are interconnected by a conductive block 20 which is screw bolted together by means of screw and bolt arrangement 21, 22. Fig. 3 illustrates a sectional view through the line A-A' of Fig. 2 showing the arrangement 5 in an assembled form. Fig. 4 illustrates an exploded perspective of the internal portions of a termination 10 block unit e.g. 12. The core of this unit is a clamping unit 25. An engaging unit 26 includes an Allen keyed screw that is thread screwed through thread hole 32 of conductive arm 17. The conductive arm is inserted in a matting slot e.g. 30. The matting slot is formed in a dove-tail arrangement for engaging the arm. A sector cable e.g. 15 is inserted into aperture 34 and the clamping unit 26 is screw tightened around the end of 15 the sector cable 15. Tap-off cables 27 can be inserted into apertures e.g. 35 and clamped via Allen key screws e.g. 28, 29. Apertures 36-38 (Fig. 3) are provided in the outer insulating casing for screw tightening so that all cables are firmly engaged by clamping unit 25. Returning to Fig. 2, in assembly, the two termination block units 11, 12 can first be 20 assembled around corresponding sector cables 15, 16 and screw tightened. Any required tap-off cables e.g. 37, 38 can also be added. Subsequently, the two termination block units can be screw bolted together via screw bolt 21,22 and conductive spacer 20 and the cover 10 placed over the bolt. The arrangement also allows for rapid disassembly and breaking of a connection 25 by undoing the screw bolt 21,22 and removing the spacer 20.

WO 2004/098008 PCT/AU2004/000543 -7 Alternative arrangements are possible. For example, occasionally it may be necessary to provide for a single sector cable termination. This can be readily provided by providing a modified termination block unit 11 that does not include the projection 17 with the top of the unit having an insulating cover over its whole surface. Such an 5 arrangement is shown in Fig. 11. In a further embodiment, there is provided an alternative compact form of single, double and triple sector cable termination. Turning initially to Fig. 5, there is illustrated a further embodiment two sector cable termination 100 in an assembled form. The arrangement is made up of four 10 identical termination units 120. The two cable termination is designed to terminate and conductively interconnect the two sector cables 101, 102. The arrangement 100 also provides for tap-off capabilities for tapping off tap-off cables e.g. 104, 105. The arrangement 100 is shown with an injection moulded plastic insulation cover formed from two parts 108, 109 and can include rubberised caps e.g. 116 for insertion into an 15 Allen key access hole. A spacing element 117 is also provided so as to allow proper initial set-up of the two cables 101, 102. Fig. 6 illustrates a side perspective view of the internal conductive portions of the arrangement 100. The part 109 of Fig. 5 covers and insulates a series of tap-off interconnection block arms 110, 111. These arms engage with a central interconnect 20 112 which includes first and second profiled apertures 113, 114 for insertion of a sector cable. Fig. 7 illustrates a cross-section through a single termination unit 120 in an assemble form. The two screw bolts 121, 122 act to firmly engage the stripped ends of the sector cables 101, 102 against the sides of the central interconnect 112. The screw WO 2004/098008 PCT/AU2004/000543 -8 bolts are activated by an Allen key inserted after removal of caps e.g. 116. Similarly the tap-off cables e.g. 105, can be engaged by screw bolts 125, 126. Advantageously, the central interconnect 112 can be formed from an extruded cross-section subsequently sliced into units. The tap-off interconnection blocks can also 5 be formed from an extruded section with a slot 128 cut therein and holes e.g.. 129, 130 drilled and tapped. Attached to the screw bolt 121 is a profiled piece 132 for urging against the sector cable upon tightening of the screw bolt. The piece 132 can be retained by hollow cap 133. 10 Turning now to Fig. 8, there is shown a further alternative embodiment 200 in an assembled form. The arrangement 200 is designed to terminate three sector cables 201, 202, 203 and consists of two substantially identical termination units 204, 205, each having two protective covers e.g. 206, 207. Fig. 9 illustrates a section view through the arrangement of Fig. 8. The 15 arrangement of Fig. 9 is similar to that of Fig. 7 however, in this instance no tap-off facility is provided and the middle sector cable 203 is passed through the bottom unit 205 and is also engaged by the top unit 204. Screw bolts e.g. 210-213 are provided for engaging corresponding portions of each sector cable against central interconnects e.g. 215, 216. The arrangement 200 providing a compact method of terminating three sector 20 cables together in a rapid and compact manner. Further extension to the overall system are possible. For example, Fig. 10 illustrates an adaptation of the unit 11 of Fig. 2 to serve as a neutral interconnection where the unit 11 includes the protruding portion 17 to which a connector block 301 is bolted and attached to a flexible cable and grounding spike 304.

WO 2004/098008 PCT/AU2004/000543 -9 Further, Fig. 11 shows a further arrangement 400 used to terminate one sector cable 401 and provide a tap-off capabilities. In this arrangement, the unit 11 is again utilised with a snug fitting insulating cap 402 to provide for safe termination and tap-off. The embodiments provide a convenient and compact arrangement for the rapid 5 termination of sector cable type arrangements. The convenience is further facilitated by the provision of tap-off cable capabilities so that distribution capabilities are also provided. The compact form of the arrangement of the embodiments enables the system to be implemented in side small cavities such as that provided by street light poles or pillars or the like. 10 It will be evident that the preferred embodiment has a number advantages. These include: Normally, it is very difficult to line up and terminate three sector cables. This is especially the case with stranded cable as the installer is required to accurately align three separate stranded cables. Also, it was previously considered a difficult task to 15 provide for the ability to clamp three separate sector cables in an aligned manor whilst simultaneously providing tap-off capability. Further, the arrangement disclosed can be manufactured inexpensively and provides for fully insulated touch safe assembly. The assembly can be rapid. Further, the positioning bracket allows for effective initial alignment of cables which later can be 20 rapidly assembled. Further, the tap-off capability are easily accessible, again providing for rapid interconnection of taped off distributions. The foregoing describes preferred forms of the present invention only. Modifications, obvious to those skilled in the art can be made thereto without departing from the scope of the invention. Additionally, stylistic changes can be made in the final 25 form of preferred embodiments of the invention.

Claims (14)

1. A cable termination and interconnection system comprising: a conductive unit for conductively clamping around a sector cable; 5 at least one tap-off hole formed within said conductive unit for insertion of at least one conductive electrical tap-off cable; and interconnecting means for conductively interconnecting at least a first and second conductive unit so as to provide electrical interconnection between at least a first and second sector cable. 10

2. A system as claimed in claim I wherein said interconnecting means is detachably mounted to said conductive unit.

3. A system as claimed in claim 2 wherein said system further includes a nonconductive cover including apertures for the insertion of said sector cables there through. 15

4. A system as claimed in claim 3 wherein said interconnecting means includes a conductive protrusion projecting from said conductive unit through said non-conductive cover, said conductive protrusion including engagement means for engaging with said second corresponding detachable conductive unit.

5. A system as claimed in claim 4 wherein said engagement means comprises a 20 conductive block engaging a corresponding profiled surface on each said conductive protrusion in a detachable interconnection. - 11

6. A system as claimed in any previous claim wherein each said sector cable is clamped to a corresponding conductive unit by a clamping screw engagable with said sector cable through a threaded aperture in said conductive unit.

7. A system as claimed in any preceding claim wherein said sector cables are 5 interconnected such that they are parallel to each other.

8. A system as claimed in claim 7 wherein said at least one tapoff hole includes a corresponding secondary hole for the insertion of engagement screws for engaging said tapoff cables in said tapoff holes.

9. A system as claimed in claim 8 including a plurality of said tapoff holes, each 10 having said corresponding secondary holes.

10. A system as claimed in claim 9 wherein said tapoff cables are connected substantially parallel to said sector cables.

11. A system as claimed in any preceding claim wherein said tapoff cables are of a smaller diameter than said sector cables. 15

12. A system as claimed in any preceding claim further comprising a base plate having an alignment structure formed on the surface thereof, said base plate utilised in practice to align each said sector cable in a predetermined relationship with its corresponding conductive unit.

13. A system as claimed in claim any preceding claim wherein said conductive unit is 20 formed from an extruded material having been sliced into sections. - 12

14. A cable termination and interconnection system substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.