Background of the Invention In recent years, the utilization of underground power distribution systems has become increasingly popular.

These systems have normally been standardised around a three phase cable which includes separate sector cables for each phase in addition to a neutral line. Turning to Fig.

1, there is illustrated a standard form of underground cable which includes a plastic jacket 2 encasing four section cables eg. 1. In Fig. 2, there is shown the form of a single sector cable 1 which in turn includes a plastic jacket 3 surrounding an aluminium conductive core 4 which is normally made up of closely packed aluminium wires 5 or a solid extruded aluminium portion and has a tear drop cross sectional profile.

Recently, it has become increasingly popular to provide for an underground interconnection to the power cable 2 of Fig. 1. This is popularly achieved through the utilization of a piercing connector. The piercing connector systems often utilize an outside piercing block which has a number of"dagger"shaped protrusion which pierce through the jackets 2 and 3 so as to form an electrical interconnection with the cores 4. Underground connectors are commonly known as T-joint connectors.

The utilization of piercing connectors is not without problems. For example, most underground cables, being constructed from aluminium, will undergo a certain degree of creep and thermal expansion and contraction over time.

In time, therefore, the piercing interconnect may provide less and less of an electrical interconnection with the core portions of the cable. Hence, the current carrying

capabilities of a piercing interconnect are likely to be lessened over time.

Further, with underground cabling interconnections, it is necessary to assume that the cable may be immersed in water and the interconnection should continue to function properly. This normally necessitates encasing the piercing interconnect system in a full block of resinous material.

Recent resins utilized have been found to be carcinogenic such that certain authorities have ordered their use to be discontinued. Further, the utilization of a resin based compound make it extremely difficult for alteration of the interconnection system once in place. The piercing connector systems therefore include a number of significant disadvantages.

Summary of the Invention It is an object of the present to provide for an alternative form of electrical interconnect with an underground cable or the like and to facilitate a more useful interconnection system.

In accordance with a first aspect of the present invention, there is provided a power connection system for interconnecting with a power cable, the power cable including an outer non-conductive jacket and at least one internal conductive conduit, the system comprising: a first clamping unit for clamping around the cable, the clamping unit including a series of apertures; a cable surface removal unit for insertion in the aperture and adapted to provide for the removal of portions of the non-conductive jacket adjacent the aperture; a connector unit for insertion into the aperture after the removal; the connector unit providing for a conductive interconnection with the at least one internal conductive conduit.

The connector unit preferably can includes adjustment means interconnected to the first clamping unit for compressing the connector unit against the conductive conduit. The connector unit can be adapted to be

resiliently compressed against the conductive conduit. The resilient compression can be provided by a resiliently compressible non conductive material such as polyurethane.

The connector unit preferably can includes portions which closely fit with the aperture and are preferably adapted to be expanded by compression so as to substantially seal against the wall of the non-conductive jacket.

The cable surface removal unit preferably can includes an auger attached to a handle, the auger adapted to remove the portions upon turning of the handle and the cable surface removal unit preferably further includes a guide unit for insertion in the first clamping unit aperture and the auger can be adapted to be inserted through the guide unit. Alternatively, a slot drill could be utilized.

The first clamping unit preferably applies a non uniform force around the power cable, the non-uniform force being maximised in the area of the internal conductive conduits.

Alternatively, the clamping unit can comprise a colour coded block having a series of tap offs for insertion of cables for providing for power tap of the main cable.

The system can further preferably also include mating shell covering portions adapted to be clamped around the cable, the first clamping unit and the connector unit so as to provide for a further fluidic seal around the power connection system. The mating shell can be adapted to be filled with a high quality low toxicity polyurethane material and includes a series of slots through which conductive wires are preferably inserted for interconnection with the connector unit. The mating shell can be of an elongated form when attached to the new cable the elongation being substantially parallel to the power cable.

In accordance with a further aspect of the present invention, there is provided a power cable comprising: a

series of sector cables; an opaque outer jacket surrounding the sector cables wherein the outer jacket includes at least one indicator on the surface thereof indicating the position of the sector cables within the jacket. The indicators are preferably distinguishable from one another.

The indicators can comprise a series of surface indentations on the jacket or printing on the outer jacket.

In accordance with a further aspect of the present invention, there is provided a power connection system for conductively interconnecting with a power cable, the power cable including an outer non-conductive jacket and at least one internal conductive conduit, the system comprising: at least one clamping unit for clamping around the cable, the clamping unit including a series of apertures; the clamping unit including a profiled surface including at least one raised lip, the profiling being utilized to locate at least one aperture against a corresponding one of the internal conductive conduits.

In accordance with a further aspect of the present invention, there is provided a power connection system for conductively interconnecting with a power cable, the power cable including an outer non-conductive jacket and at least one internal conductive conduit, the system comprising: at least one clamping unit for clamping around the cable, a pressure application unit mounted on the clamping unit; the clamping unit including a profiled surface including at least one raised lip, the profiling being utilized to locate the pressure application unit against a corresponding one of the internal conductive conduits.

The raised lip can be formed substantially perpendicular to the cross-sectional circumference. The pressure application unit can comprise a screw bolt and a resilient washer, the screw bolt being adjustable so as to resiliently compress the washer against the internal conductive conduit. The clamping unit can comprise two portions bolted together around the power cable. The power

cable preferably can include four internal conductive conduits each having an insulating sheath, the internal conduits being arranged to have a substantially circular cross-sectional circumference.

Preferably, the cable surface removal unit comprises an auger having a hollow core and wherein the portions removed are captured in the hollow core for examination upon removal of the cable surface removal unit. The cable surface removal unit can have a metallic end formed within a non conductive sheath.

In one embodiment the connector unit can include a conductive spiked end which mates with the internal conductive conduit.

Brief Description of the Drawings Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figs. 1 and 2 are perspective views of standard underground sector type cables in common use; Fig. 3 is an exploded perspective view of a first portion of an embodiment; Fig. 4 illustrates one form of marking of a sector cable which would be advantageous in the utilisation of an embodiment; Fig. 5 illustrates a cutting tool utilised for removing a portion of the exterior casing of a cable; Fig. 6 is an exploded perspective view illustrating further portions of an embodiment; Fig. 7 is an exploded perspective of an alternative embodiment; Fig. 8 is an exploded perspective of the clamping units of the alternative embodiment; Fig. 9 is an exploded perspective of the connector blocks of an alternative arrangement;

Fig. 10 illustrates a cutting tool utilised for removing a portion of the exterior casing of a cable in an alternative embodiment; Fig. 11 illustrates an assembled alternative arrangement; Fig. 12 is an exploded perspective view of an alternative embodiment; Fig. 13 is an enlarged sectional view of a cable; Fig. 14 is an exploded perspective view of a further alternative embodiment; and Fig. 15 is a sectional view of an alternative embodiment.

Description of Preferred and Other Embodiments In a first embodiment of the present invention, a clamping arrangement is placed around the cable 2 with the clamping arrangement also providing for forming an electrical contact with the core portions of the cable. In this embodiment, the degree of piercing of the outer casing 2 is minimised so as to provide for improved water resistant sealing properties.

Turning now to Fig. 3, there is illustrated a first portion of an embodiment 10 which is adapted to provide for an electrical interconnection with a cable 2. The first portion 10 is based around two extruded aluminium sections 11,12 which are clamped together around the cable by means of bolts 13,14. The extruded sections 11,12 can be symmetrical and include a series of lips eg. 15 which provide for selective compression of the cable 2 at the point of insertion of the interconnect. The general compression of the cable 2 results in minimisation of the opportunity for inflow of water inside the cable 2 as a result of the utilization of the arrangement 10.

Around each sector cable 3, there is supplied a connector arrangement 16-19 with the arrangement 19 being illustrated in an exploded perspective. The connector arrangement 19 includes a first deformable sealing element

20, a plastic insulating element 21 both through which is inserted a conductive core 22 which conductively connects to, and further compresses against, the strands of the sector cable. Next, a resiliently compressible material 23 which can be formed from polyurethane is provided which acts as a compression spring against the conductive core 22. A screw bolt cover 25 is provided for screwing into a mating thread in aperture 27. An 0-ring 24 can optionally be provided for.

Hence, the connector arrangements are inserted into corresponding portions of the arrangement 10 with the tightening screw bolt 25 providing for further compression of the conductive element 22 against the surface of a corresponding cable. The tightening of screw bolt 25 also forces the deformable member 20 to be deformed into the space around the conductive core 22 adjacent to the jacket of the core of the sector cable thereby providing a sealing of the exterior of the cable 2.

The plastic element 21 in addition to the conductive core 22 are provided with apertures which mate with the aperture 28 which can include a plastic non-conductive insert. Inserted in the aperture 28 is also an output cable for providing output from the connection arrangement 10.

Preferably, during operation, the two extruded sections 11,12 are first bolted around a requisite position in the cable. The orientation of the extruded sections 11,12 is preferably determined beforehand so as to align the orientation of the arrangement 10 with the underlying sector cable.

Unfortunately, underground cabling does not contain indicators of the sector positions. However, it is often the case that the cable is not completely circular and consists of four bulges at the position of each sector cable. In such cases, the positions of each sector cable can be determined through the utilization of a separate

clamping tool which can comprise two semi circular extruded portions which are clamped together and include a raised edge which is clamped around and cuts into a minor amount the surface of the cable. The degree of cutting will be somewhat proportional to the degree of bulge such that four marks will be left of the surface of the cable when the clamping arrangement is removed with the marks indicating the position of the bulges for alignment for utilizing the arrangement 10.

It is an envisaged that more accurate positioning can be readily provided through the utilization of an indicator on the outside surface of the cable 2. This can take the form of a colour printed indicator or alternatively, as indicated in Fig. 4, a series of minute serrations can be placed along the surface of the cable when manufacturing the cable with the serrations being provided as an indicator of the position of the underlying sector cable.

Further, the serrations eg. 30 can be spatially coded for instant visual recognition. For example, the neutral line 30 may contain 2 closely parallel lines of serration whereas the other phase lines 31 may for example, contain only one line of serrations. Alternatively, exterior printed colour indicators may be utilized or deforming of the exterior surface during manufacture by moulds.

Returning now to Fig. 5, as previously discussed, the first step is to properly align the extruded sections 11, 12 around the cable 2 and to clamp them so as to compress the cable.

Next, as indicated in Fig. 5, a separate cutting tool is utilized for insertion in the aperture 27. The tool includes an outer mating portion 33 which is screwed into the aperture 27. A cutting unit 34 which includes a handle 35 and a cutting end portion 36 is inserted through the element 33 so as to form a contact with the outer plastic surface of the cable 2. The handle 35 is electrically insulated and, upon turning, the cutting blade 36 cuts

through the outer plastic sheaths of cable 2. The handle 35 is rotated until such time as the inner core portions (4 of Fig. 2) are reached. It has been found in practice that there is a marked distinction in the force required to cut through the plastic as opposed to cutting through the internal conductive portions so the completion of the jacket cutting process is readily discernible. The size of the cutting end portion 36 is dimensioned so that a small circular hole is formed which neatly mates with the end of the element 21 so as to form a tight seal. Hence, after cutting through the outside casing, the tool elements 33, 34 are removed and the arrangement 19 of Fig. 3 is inserted so as to provide for the conductive tapping off an electrical interconnect. Next, as illustrated in Fig. 6, the arrangement 10 having, for example, conductive wires 40,41 being taped off the cable 2 are inserted in corresponding apertures and clamped, a plastic casing 44, 45 is encased around the arrangement 10 so as to provide for a protective covering. The portions 44,45 being bolted together and including slots, eg. 46 for the cables 40,41. Preferably, the outer casing 44,45 includes an aperture (not shown) such that when formed together, it can be filled with a hard setting high quality low toxicity polyurethane material and hardener. The polyurethane material can be pumped inside the casing before setting so to fully encase the arrangement 10 in a further waterproof protective element. Alternatively a silicone grease or other silicone material could be utilized but this would be non-optimal. The outer casing 44,45 is also preferably profiled so as to allow for the dragging of the cable 2 along surface without substantial opportunities for "catching"of the external surface of the portions 44,45 with objects. This helps facilitate the movement of cable 2 when inserted in an underground trench or the like.

The first illustrated embodiment therefore has a number of advantages over the prior art. Firstly, no

stripping of the outside cable is required with only 4 small round holes made in the outside surface of the jacket to make for an electrical interconnection with the sealing ring eg. (20 of Fig. 3) providing for compressed sealing of the holes. Further, the area under connection is under compression via two means. Firstly, via the extruded portions and secondly, by means of the screw bolt 25 and resilient spring type element 23. In this manner, the compression of the cable minimises the opportunity for fluid flow into the cable. Additionally, the utilisation of a spring element assists in reducing the opportunities for creep in the aluminium affecting the condition of the contact between the cable and the exterior current supply.

Further, the embodiment dispenses with the need for the utilisation of an excessive amount of resin and further is able to be quickly assembled when required. Further, the embodiment allows for more convenient access for the testing or the working of the cable interconnection 2 or for testing of the cable state itself. It can further be operated in a live manner through the utilisation of appropriate non-conductive elements. Further, the current load can be more substantial than when utilising a piercing connector as the interconnection is not affected as much over time by creep and further a non-point contact is provided. Hence, heavier duty loads can be safely interconnected to the cable 2 which provides for a more economical power distribution system.

Turning now to Fig. 7 to Fig. 11, there will now be discussed a second embodiment of the present invention. In Fig. 7 the cable 2 is clamped by two clamping units 51,52.

The clamping process is more readily illustrated in Fig. 8 which shows an exploded perspective of the clamping operation. Again the camping units include a series of suitably raised lips e. g. 54 which are positioned to provided extra pressure against the cable wall as previously described. The clamping units 51 have the

advantage that they can be formed from a suitably machined extruded section and the bolts 56,57 sit within mating recesses.

A series of four connector block units, of which one is shown 60 in Fig. 7, are formed for snap insertion in a corresponding cavities formed in the clamping units. As illustrated in Fig. 9, each connector block 60 can comprise a conductive core 61 around which is formed an insulating jacket e. g: 62,63. The core 61 includes a post 65 which interconnects with the cable core through hole 66 (Fig. 7).

Four"tap off holes"e. g. 68 are provided, with appropriate interconnecting screw holes e. g. 69, for insertion of cables for power tap off.

As shown in Fig. 7, a rubber ring or 0-ring 70 is provided for sealing the post 65 in the hole 66. The post 65 is urged against the cable core by means of T-section unit 71, screw bolt 73 and resiliently compressible plug 72.

The hole 66 can be formed in a similar manner to that shown in Fig. 5 with the operation slightly modified as illustrated in Fig. 10 with the arrangement of Fig. 10 providing for the formation of a slightly larger hole.

The arrangement of Fig. 7 can be utilized to form up to four tap off'cables as illustrated in Fig. 11. The four cables 80-83 each can provide 3 single (and neutral) outlets or a full 3 phase outlet with the connector blocks 85-87 preferably being colour coded to match the colour coding of the phase cables and the color coding of the sector cables within cable 2. The utilization of colour coding allows for minimisation of errors due to incorrect interconnection.

The arrangement of Fig. 11 can further include a suitably moulded cover 90 having a predetermined number of holes for tap off cables 80-83. Again, a suitable filler material as previously discussed can be used.

The arrangement of Fig. 11 provides for a highly compact means of interconnecting a large number of cables to an underground sector cable or the like in the form of a T-joint connector.

Turning now to Fig. 12, there is illustrated a further alternative embodiment 100. In this embodiment, 2 connector blocks 101,102 are provided having very similar structure to the arrangement of Fig. 6 but for a number of refinements. It has been found generally that a combined cable eg. 103 having a number of tear dropped shaped sector cables therein 104-107 generally takes on a slightly irregular shape. This is illustrated in more detail in Fig. 13, wherein the casing 109 of the cable 103 undergoes deviation from a perfect circle 110 as a result of the sector cables eg. 104,105 bulging out and causing the distortion in the outer casing 109. Hence, the arrangement of Fig. 12 includes the connector blocks 101,102 having a positioning lip eg. 111,112 which is utilized so as to position the blocks 101,102 around the cable 103. Hence, the mode of operation is to first utilize screws 115,116 to join the two blocks 101,102 around the cable 103 in a loose fit. The connector blocks come complete with a series of"snap on"insulating washers or compression pads eg. 117 with the washer 117 snapping on to the portion 118 of the block 102. A second washer eg. 120 snaps on to the edge 121 of connector block 101. The other edges 122,123 also contain washers although this is not shown in Fig. 12 to maintain clarity. The washers can be formed from a tough glass filled nylon type material.

As mentioned previously, the two connector blocks 101, 102 are joined together and screwed tightly using screws 115 and 116 so as to join the two blocks together around the cable 103 in a somewhat loose fit. As the blocks are tightened together they can be rotated through a small angle so as to centrally locate the lip 111 at the point of minimum radius (as shown in Fig. 13). In this manner, the

system"auto locates"the screw holes eg. 125 above a corresponding portion of sector cable.

Subsequently, once properly located, a series of screws eg. 119 are provided for insertion in corresponding screw holes eg. 125. Although only one screw 119 is shown, it will be understood that a maximum of up to four screws and compression pads can be utilized. Subsequently, the screws 119 are slowly tightened in sequence to compress the cable 103.

When it is desired to make contact with the underlying sector cable, the system as previously discussed with reference to Fig. 10 can be utilised so as to remove the outer casing. This can then be followed by the arrangement of Fig. 7 so as to provide for electrical interconnection between a corresponding sector cable and a take off cable.

The arrangement of Fig. 12 has the added advantage that the need to physically mark the cable or utilise an initial compression of the cable is dispensed with.

Further the arrangement of Fig. 12 compresses the cable utilising the four radial compression screws eg. 119 and corresponding washer 117 is resilient and, as a result, the cable is resiliently compressed.

Turning now to Fig. 14 and 15, there is illustrated a further alternative embodiment 200 with Fig. 14 illustrating an exploded perspective and Fig. 15 illustrating a sectional view. In the arrangement 200, various further refinements are made. The arrangement is directed particularly at undertaking an interconnection with a sector cable whilst it is still"live".

In the arrangement 200, a cable casing cutting tool 201, which includes a non-conductive outer case 202 and a metallic core 203 (Fig. 15), is screwed into the T-section 204 and gradually tightened such that a metallic end 205 cuts into the outer casing forming an access path to a sector cable 206. The cutting tool 201 is then removed and a poker (not shown) inserted in core 207 so as to extract

the two casing sheet samples 209,210. The inner sample can then be examined so as to determine which portion or phase of the sector cable to which contact has been made.

Importantly, the cutting of the sector cable outer casing is done utilising cutting tools 201 which contains a outer insulted casing and hence the extraction process is carried out without the opportunity for touching a live sector cable 206 where live operations are carried out.

Subsequently, a connector block can be utilized to conductively attach cables to the sector cable as previously described. In Fig. 14 and 15, there is illustrated a modified connector block 220 which is similar to the previously described connector blocks in that it includes a conductive core 221 having a plastic casing 222.

The conductive core includes an end portion 223 which is profiled into a point 224. A slot 226 is provided for the insertion of tap off electrical cables which are held in place by means of screws 227,288.

The T-section portion 229 and screw 230 mate with slots 232 such that the connector bolt 220 is driven into the sector cable 235. The point 224 on the end of the connector block deforms the sector cable so as to provide for an improved interconnect thereto.

The arrangement of Fig. 14 and Fig. 15 also includes a locator lip eg. 240 and resilient washers eg. 241 which operate in a similar manner to that previously described.

The arrangement of Fig. 14 and Fig. 15 has the advantage that a live interconnection to a sector cable can be carried out without the operator being exposed to a high risk of electrocution.

It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive.