NZ543603A - A cable terminal lug - Google Patents

Abstract

A cable terminal lug has a barrel (101, figure 2) defining a first tunnel (103, figure 4) for receipt of a mains cable core strand. A palm 102 extends from the barrel 101 and defines a first flat face (104, figure 4). A mounting aperture extends through the palm 102 perpendicularly to the face 104. A first threaded aperture (110, figure 2) extends through a wall of the barrel 101 into the first tunnel 103. A first fastener (111, figure 2) is received in the first threaded aperture 110 and has a leading end (111a, figure 3) which can extend into the first tunnel 103. A second tunnel (112, figure 3) is provided for receipt of a cable, and a second threaded aperture (113, figure 2) intersects the second tunnel and receives a second fastener (114, figure 2) which has a leading end (114a, figure 4) which can extend into the second tunnel 112. A mounting portion 140 is provided for mounting a link disconnect device.

Description

54 3 60 3 *10049841290* PATENTS FORM 5 PATENTS ACT 1953 COMPLETE SPECIFICATION OurRef: 687135NZD1 Dated: 15 November 2005 A cable terminal lug We, Cable Accessories (Australia) Pty. Ltd an Australian company, ACN 002 184 616, of 26 Derby Street, Silverwater, New South Wales, 2128, Australia, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 1 A CABLE TERMINAL LUG Field of the Invention The present invention relates to cable terminal lugs, and particularly relates to cable terminal lugs for mains power cables.

Background of the Invention Underground mains power cables, utilised for residential power distribution, are buried within the ground and have their ends extending up through the ground surface where they are terminated in distribution units, from where service cables that distribute power to individual properties are joined. A typical arrangement within such a distribution unit is depicted in Figure 1.

Each mains power cable 1 typically comprises four core strands 2 of aluminium wires that are each individually sheathed. The four sheathed core strands 2 are retained within a mains cable sheath 3.

To terminate the mains cable within the above-ground distribution unit 4, a length of approximately 300 mm of the cable 1 is exposed above the ground surface 5, and each of the four core strands 2 are separated by removing the mains cable sheath 3 above the ground surface 5. Each of the four core strands 2 is then terminated by crimping the barrel 6 of a standard crimping-type cable terminal lug 7 onto the exposed wires at the end of each core strand 2. Heatshrink tubing (not depicted) is applied to the terminal lug barrel 6 and adjacent portion of sheathed core strand 2. The four terminated core strands 2 are divided into two pairs, with each pair of terminated core strands 2 being joined by way of a bolt 8 and bus bar 9. The bolt 8 passes through the aperture in the palm 10 of one of the terminal lugs 7, through the corresponding aperture in the bus bar 9 and then through the aperture in the palm 10 of the second terminal lug 7, with a nut completing the connection.

Service cables 12, which are routed to individual properties for distribution of power to those properties, are also terminated in the distribution unit. Again, these service cables 12 are terminated by crimping a crimping-type cable terminal lug 13 onto the exposed end of the cable 12. The terminated service cables 12 are connected to the mains cable 1 by passing the bolt 8 securing a pair of mains cable core strands 2 together through the aperture provided in the service cable terminal lug 13. An earth cable 14 is similarly terminated by a crimping-type cable terminal lug and connected to the mains cable in the same manner as a service cable. Lighting power cables (not depicted), which [R:\LIBLL]687135nzspeci.doc:GXT 2 provide power directly to street lighting, are also terminated by way of a crimping-type cable terminal lug and are connected to one of the core pair assemblies by way of the bolt 8. Each core pair assembly is then covered in heatshrink material.

The mains cable core strands 2 typically have a cross-sectional area of 5 approximately 240mm2 (for aluminium wire core strands), whilst the service and earth cables are much smaller, typically having a cross-sectional area of approximately 50 mm . The lighting cables are smaller again, with a cross-sectional area of approximately 10 mm2. Terminating these three varying sized cables requires a range of expensive crimping tools and associated dies. These crimping tools and dies, apart from being 10 rather expensive, require frequent maintenance and are often poorly maintained, resulting in poor quality terminal connections. Lack of operator skill and care also compromises the quality of the terminal connections.

The process of crimping a cable terminal lug onto a cable, particularly a large mains cable core strand, can also be quite tedious. When a pair of mains cable core 15 strands 2 are to be connected by way of a bus bar 9, the cable terminal lugs 7 also need to be closely aligned when secured to the cable core strand 2, as the short length of cable core strand 2 protruding from the ground surface 5 cannot be readily twisted into alignment. Even when the cable terminal lug 7 appears to be aligned prior to operation of the crimping tool, movement of the cable terminal lug 7 as the tool is applied often 20 occurs, resulting in misaligned cable terminal lugs 7 which cannot be readily connected by way of a bus bar 9.

There is at times a need to disconnect sections of an electrical power distribution system whilst under electrical load. For example, it may be necessary to disconnect a section of the service side of the system servicing a group of properties to perform some 25 form of maintenance or to install further service cables to that group of properties.

Alternatively, it may be necessary to isolate one transformer providing mains electrical power supply to a section of the system, whilst allowing another nearby transformer to provide power to that section.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages and to satisfy the above need.

[R:\LIB LL]687135nzspeci.doc:GXT 3 Summary of the Invention There is disclosed herein a cable terminal lug comprising: a barrel defining a first tunnel for receipt of a mains cable core strand, said first tunnel opening onto a first longitudinal end of said cable terminal lug; a palm extending from said barrel and defining a generally flat first face; a bus bar mounting aperture extending through said palm generally perpendicular to, and extending through, said first face; a first threaded aperture extending through a wall of said barrel into said first tunnel; a first fastener threadingly received in said first threaded aperture, said first fastener having a leading end extendable into said first tunnel; a second tunnel for receipt of a first cable; a second threaded aperture intersecting said second tunnel; a second fastener threadingly received in said second threaded aperture, said second fastener having a leading end extendable into said second tunnel; and a mounting portion for mounting a link disconnect device, said mounting portion extending from said palm to a second longitudinal end of said cable terminal lug, said mounting portion including a first contact surface for engaging a first conductive portion of a link disconnect device and a second contact surface for engaging a second conductive portion of a link disconnect device.

The first contact surface and second contact surface may extend in substantially parallel planes to said longitudinal second end of said cable terminal lug, said substantially parallel planes being substantially parallel to a longitudinal axis of said cable terminal lug.

The first contact surface and second contact surface may be defined on opposing sides of a mounting recess configured to receive the link disconnect device.

Alternatively, the first contact surface and second surface may be defined on opposing sides of a mounting post configured to be received by the link disconnect device.

There is further disclosed herein a power distribution connection comprising: a first cable terminal lug as defined above; a second cable terminal lug as defined above; and [R:\LIB LL]687135nzspeci.doc:GXT 4 a link disconnect device having opposing ends thereof mounted on said mounting portion of said first cable terminal lug and said mounting portion of said second cable terminal lug respectively, said link disconnect device having a first conductive portion engaging said first contact surface of each of said first cable terminal lug and said 5 second cable terminal lug and a second conductive surface engaging said second contact surface of each of said first cable terminal lug and said second cable terminal lug.

Brief Description of the Drawings Preferred forms of the present invention and of the invention disclosed in parent New Zealand application no. 537149 will now be described by way of example with 10 reference to the accompanying drawings, wherein: Figure 1 is a front elevation view of a power distribution connection according to the prior art.

Figure 2 is a perspective view of a cable terminal lug.

Figure 3 is an inverse plan view of the cable terminal lug of Figure 2. 15 Figure 4 is a side elevation view of the cable terminal lug of Figure 2.

Figure 5 is a front elevation view of a power distribution connection utilising the cable terminal lug of Figure 2 with a single mains cable core strand.

Figure 6 is a side elevation view of the power distribution connection of Figure .

Figure 7 is a front elevation view of a power distribution connection utilising the two cable terminal lugs of Figure 2 with two mains cable core strands.

Figure 8 is a side elevation view of the power distribution connection of Figure 7.

Figure 9 is a front elevation view of a power distribution connection utilising 25 four cable terminal lugs of Figure 2 with four mains cable core strands.

Figure 10 is a side elevation view of the power distribution connection of Figure 9.

Figure 11 is a front elevation view of a power distribution connection utilising an alternate cable terminal lug with a single mains cable core strand.

Figure 12 is a side elevation view of the power distribution connection of Figure 11.

Figure 13 is a front elevation view of a power distribution connection utilising two cable terminal lugs with two mains cable core strands and a cover assembly.

[R:\LIB LL]687135nzspeci.doc:GXT Figure 14 is a side elevation view of the power distribution connection of Figure 13.

Figure 15 is a perspective view of the front portion of a cover assembly.

Figure 16 is a perspective view of a cable terminal lug according to an 5 embodiment of the present invention having a mounting portion for mounting a link disconnect device.

Figure 17 is a front elevation view of a link disconnect device with the locking element in the locking position.

Figure 18 is a cross sectional view of the link disconnect device of Figure 17 10 taken at cross section 18-18.

Figure 19 is a front elevation view of the link disconnect device of Figure 17 with the locking element in the unlocking position.

Figure 20 is a fragmentary cross sectional view of a connection between the cable terminal lug of Figure 16 and the link disconnect device of Figure 17, taken through 15 a horizontal plane through the mounting portion.

Figure 21 is a front elevation view of a power distribution connection utilising two cable terminal lugs of Figure 16 and the link disconnect device of Figure 17.

Figure 22 is a plan view of the power distribution connection of Figure 21.

Figure 23 is a perspective view of a cable terminal lug according to a second 20 embodiment of the present invention and having an alternate form of mounting portion.

Figure 24 is a perspective view of a cable terminal lug according to a third embodiment of the present invention having another alternative form of mounting portion.

Figure 25 is a front elevation view of a three way power distribution connection 25 utilising two cable terminal lugs of Figure 23, a single cable terminal lug of Figure 24 and two link disconnect devices of Figure 17.

Figure 26 is a side elevation view of the three way power distribution connection of Figure 25.

Figure 27 is a plan view of the three way power distribution connection of Figure 25.

Figure 28 is a perspective view of a cable terminal lug according to a fourth embodiment of the present invention and having yet another alternate form of mounting portion.

[R:\LIB LL]687135nzspeci.doc:GXT 6 Detailed Description of the Preferred Embodiments Referring particularly to Figures 2 to 4, a cable terminal lug 100 as described in New Zealand Patent application No. 537149 has a barrel 101 and a palm 102 extending from the barrel 101. The barrel defines a first tunnel 103, best depicted in Figure 3,. which opens onto a first longitudinal end of the cable terminal lug 100 and is sized to receive a mains cable core strand 2. Here the tunnel 103 has a cross-sectional area, as viewed in the inverse plan view of Figure 3, of approximately 240 mm such that it can neatly receive a typical 240 mm2 cable core strand 2. The tunnel 103 has a depth of the order of 60 mm, terminating in a blind end face immediately below the palm 102. 10 The palm 102 defines a generally flat first face 104 and a second face 105 opposing the first face 104. The second face 105 will also typically be generally flat. An end surface 106 extends between the first and second faces 104,105 of the palms at the end of the palm 102. First and second side walls 107,108 extend between the first and second faces 104, 105 of the palm along respective sides thereof. A bus bar mounting 15 aperture 109, here having a diameter of approximately 12 mm, extends through the palm 102 generally perpendicular to, and extending through, the first and second faces 104, 105.

A first threaded aperture 110 extends through a wall of the barrel 101 into the first tunnel 103. A first fastener 111 is threadingly received in the first threaded fastener 20 aperture 110. Upon threading the first fastener 111 into the first threaded fastener aperture 110, the convex leading end 11 la of the first fastener 111 extends into the first tunnel 103 for engagement with a cable core strand 2 inserted into the first tunnel 103. The first fastener 111 may be a shear head bolt, designed such that the head of the bolt shears upon exceeding a pre-determined torque load, thereby preventing overtorquing of 25 the shear head bolt. The first fastener 111 is provided with an alien key type drive socket 111b.

A second tunnel 112 is provided for receipt of a cable, typically either a service cable 12 or earth cable 14, and has a cross-sectional area of approximately 50 mm . The second tunnel 112 may alternatively receive a cross-road cable that is used to supply 30 mains power to a cable terminal lug in a power distribution unit on the opposing side of the road, thereby avoiding the need to run mains cables along both sides of the road. If only service cables 12 or earth cables 14 are to be received in the second tunnel 112, the second tunnel may have a smaller cross-sectional area of approximately 25 mm2, given that service and earth cables are typically smaller than cross-road cables.

[R:\LIBLL]687135nzspeci.doc:GXT 7 The second tunnel 112 is located in the palm 102 and extends generally parallel to the first face 104 between the first and second side walls 107,108 of the palm 102. The second tunnel 112 may open onto both the first and second side walls 107,108, allowing the cable to be inserted from either side, or may have one blind end. Here the 5 second tunnel 112 is located between the mounting aperture 109 and the palm end surface 106. A second threaded aperture 113 extends through the palm second face 105 and intersects the second tunnel 112. A second fastener 114 is threadingly received in the second threaded aperture 113. Threading the second fastener 114 into the second fastener aperture 113 extends the convex leading end 114a of the second fastener 114 into the 10 second tunnel 112 for engagement with a cable 12,14 inserted into the second tunnel 112. The second fastener 114 may be in the form of a grub screw/set screw, and is provided with an alien key type drive socket 1146.

A third tunnel 115 is provided for receipt of another cable, again typically either a service cable 12 or earth cable 14, and has a cross-sectional area of approximately 50 2 . mm . Agam, the third tunnel 115 may receive a cross-road cable. If cross-road cables will not be received in the third tunnel 115, it may have a smaller cross-sectional area of approximately 25mm2. The third tunnel 115 is located in the palm 102 and extends generally parallel to the first face 104 between the first and second side walls 107,108 of the palm 102. The third tunnel 115 may open onto both the first and second side walls 20 107,108, allowing the cable to be inserted from either side, or may have one blind end. Here the third tunnel 115 is located between the mounting aperture 109 and the barrel 101. A third threaded aperture 116 extends through the palm second face 105 and intersects the third tunnel 115. A third fastener 117 is threadingly received in the third threaded aperture 116. Threading the third fastener 117 into the third aperture 116 25 extends the convex leading end 117a of the third fastener 117 into the third tunnel 115 for engagement with a cable 12,14 inserted into the third tunnel 115. The third fastener 117 is here identical to the second fastener 114, being a grub screw/set screw with an alien key type drive socket 117b.

To comply with local regulations, each of the first, second and third tunnels 103, 30 112 and 115 is provided with a further threaded aperture and fastener to ensure a more robust connection of any cables inserted into the tunnels, each cable being engaged by two fasteners.

Accordingly, the cable terminal lug 100 includes a fourth threaded aperture 118 extending through the wall of the barrel 101 into the first tunnel 103. A fourth fastener [R:\LIBLL]687135nzspeci.doc:GXT 8 119, in the form of a shear head bolt identical to the first fastener 111, is threadingly received in the fourth threaded aperture 118. Threading of the fourth fastener 119 into the fourth threaded fastener 119 extends the leading end 119a of the fourth fastener into the first tunnel 103 for engagement with a mains cable core strand 2 inserted into the first 5 tunnel 103. The fourth threaded aperture 118 and fourth fastener 119 are radially and axially offset from the third threaded aperture 110.

A fifth threaded aperture 120 extends through the palm second face 105 and intersects the second tunnel 112. A fifth fastener 121, identical to the second fastener 114, is threadingly received in the fifth threaded aperture 120. Threading the fifth 10 fastener 121 into the fifth threaded 112 aperture 120 extends the convex leading end 121a of the fifth fastener into the second tunnel for engagement with a cable 12, 14 inserted into the second tunnel 112.

A sixth threaded aperture 122 extends through the palm second face 105 and intersects the second tunnel 115. A sixth fastener 123, identical to the third fastener 117, 15 is threadingly received in the sixth threaded aperture 122. Threading the sixth fastener 123 into the sixth threaded aperture 122 extends the convex leading end 123a of the sixth fastener 123 into the third tunnel 115 for engagement with a cable 12, 14 inserted into the third tunnel 115.

The cable terminal lug 100 may be provided with a fourth tunnel 124 extending 20 through the end surface 106 of the palm 102 and intersecting the second tunnel 112. The fourth tunnel here has a cross-sectional area of approximately 10 mm2, specifically for receipt of a small lighting cable 15. The fourth tunnel 124 is positioned such that it intersects with the second threaded aperture 113. Threading of the second fastener 114 into the second threaded aperture 113 extends the leading end 114a of the second fastener 25 114 into both the second tunnel 112 and the fourth tunnel 124, enabling engagement with cables inserted into both tunnels.

Each of the fasteners 111, 114,117,119,121,123 is formed of tin plated brass. The barrel 101 and palm 102 are integrally machined from conductive aluminium. Referring to Figures 5 and 6, a power distribution connection involving a single mains 30 cable core strand 2 is achieved by inserting the end of the mains cable core strand (after having stripped any sheathing from the end portion) into the first tunnel 103 of a cable terminal lug 100. The cable terminal lug is 100 is rotated for any required alignment. The first and fourth fasteners 111, 119 are then threaded into their respective threaded apertures 110,118 so as to engage the mains cable core strand 2 with the fastener leading [R:\LffiLL]687135nzspeci.doc:GXT 9 ends 111a, 119a. The first and fourth fasteners 111, 119 are threaded into their apertures by way of an alien key engaging the drive sockets 11 lb, 119b. Engagement of the convex leading ends 11 la, 119a of the first and fourth fasteners with the mains cable core strand 2 provides a secure mechanical and electrical connection between the mains cable 5 core strand 2 and the cable terminal lug 100. Whilst the first tunnel 103 is designed to terminate a 240 mm2 mains cable core strand 2, the connection is range-taking in that cable core strands with a cross-sectional area down to approximately 185 mm can still be securely terminated in the first tunnel 103.

The stripped end of a service cable 12 is then inserted into the second tunnel 112 10 of the cable terminal lug 100. The second and fifth fasteners 114,121 are then threaded into their respective threaded apertures 113, 120 so as to engage the service cable 12 with the fastener leading ends, 114a, 121a. Engagement of the convex leading ends 114a, 121a of the second and fifth fasteners with the service cable 12 provides a secure mechanical and electrical connection between the service cable 12 and the cable terminal 15 lug 100.

The stripped end of an earth cable 14 is then inserted into the third tunnel 115 of the cable terminal lug 100. The third and sixth fasteners 117, 123 are then threaded into their respective threaded apertures 116,122 so as to engage the earth cable 14 with the fastener leading ends 117a, 123a. Engagement of the convex leading ends 117a, 123a of 20 the third and sixth fasteners with the earth cable 14 provides a secure mechanical and electrical connection between the earth cable 14 and the cable terminal lug 100.

Alternative to the above, the earth cable 14 could be inserted into the second tunnel 112 with the service cable 12 being inserted into the third tunnel 115.

Whilst the second and third tunnel 112,115 are designed to terminate service, 25 earth or cross-road cables up to 50 mm2 (for tunnels having a cross-sectional area of 50 mm2), the connections are range-taking in that cables with a cross-sectional area down to approximately 16 mm2 can still be securely terminated in the second and third tunnels 112, 115.

If required, a lighting power cable 15 may be terminated by inserting the stripped 30 end of the lighting power cable 15 into the fourth tunnel 124 of the cable terminal lug 100 prior to threading the second fastener 114 into the second threaded aperture 131. Subsequent threading of the second fastener 114 into the second threaded aperture 113 results in engagement of the second fastener leading end 114a with both the service cable [R:\LIB LL]687135nzspeci.doc:GXT 12 and the lighting power cable 15, securing both cables. Again the fourth tunnel 124 is range-taking, accepting cables between 4 mm2 and 10 mm2.

Referring to Figures 7 and 8, a power distribution connection utilising two mains cable core strands 2 is achieved by connecting both mains cable core strands 2 to a cable 5 terminal lug 100 in the manner described above, with the cable terminal lugs 100 being aligned with the first face 104 of the palms 102 aligned parallel and facing each other. Service cables 12, an earth cable 14 and lighting power cables 15 may be terminated to either of the cable terminal lugs 100 in the manner described above. The two cable terminal lugs 100 are connected by way of an aluminium bus bar 9 positioned between 10 the palms 102 of the cable terminal lugs 100. A bolt 8 is extended through the mounting apertures 109 of the cable terminal lugs 100 and a corresponding aperture provided in the bus bar 9. A nut 11 is then threaded onto the free end of the bolt 8 to secure and engage the cable terminal lugs 100 and the bus bar 9.

Referring to Figures 9 and 10, a power distribution connection involving four is mains cable core strands 2 may similarly be achieved utilising four cable terminal lugs 100 and an elongate bus bar 9' having two apertures, each for receiving a bolt 8 passing through the mounting apertures 109 of aligned cable terminal lugs 100.

Referring to Figures 11 and 12, an alternate version of the cable terminal lug 100 is depicted which includes a fifth tunnel 125 arranged parallel to and directly above the 20 third tunnel 115 so as to provide greater flexibility and capacity for creating cable connections. In this arrangement, the second tunnel 112 has a cross-sectional area of 50 mm specifically for accepting a cross-road cable 16, whilst the third and fifth tunnels 115,125 each have a cross-sectional area of 25 mm2 for receiving the smaller earth and service cables 14,12. Cables are retained within the fifth tunnel 125 by way of threaded 25 fasteners 126, 127 in the same manner as for the third tunnel 115.

To further simplify the process of forming a power distribution connection with cable terminal lugs 100 as described above, the power distribution connection may be mounted within a cover assembly so as to avoid the need to apply heat shrink tubing to the terminal lug barrel 101 and adjacent portion of mains cable core strand 2. The need 30 for a heat gun for shrinking the heat shrink tubing is thus dispensed with. A power distribution connection formed of two mains power cables 1 terminated with cable terminal lugs 100, as per those of Figures 11 and 12, housed within a cover assembly 200 is depicted in Figures 13 and 14. The cover assembly 200 is formed of front and rear cover portions 201,202. The cover assembly front and rear portions 201, 202 are [R:\LIBLL]687135nzspeci.doc:GXT 11 mounted onto the assembled terminal lugs 100 from opposing sides. The cover assembly portions 201, 202 are then mutually fastened to each other by way of fasteners 203 extending through aligned apertures 204 provided on each corner of each of the cover assembly portions 201, 202. Each of the cover assembly portions 201,202 is provided 5 with two semi cylindrical openings at the base thereof which, when the two cover assembly portions 201,202 are fastened together, define a cylindrical opening through which the mains power cables 1 extend. The cover assembly 200 is mounted on the power distribution connection once the mains power cables 1 have been terminated and the terminal lugs 100 interconnected, but prior to connecting various secondary cables 10 such as surface cables 12, earth cables 14, lighting power cables 15 or cross-road cables 16 to the terminal lugs 100.

To enable such secondary cables to be connected to the terminal lugs 100, various apertures are provided in both the front and/or rear cover assembly portions 201, 202. As depicted in Figure 15, cross-road cable entry apertures 206 are provided toward 15 the top of the face of the front cover assembly portion 201, aligned with the second tunnel 112 of each terminal lug 100, enabling a cross-road cable (or other type of cable as desired) to be passed through the cover assembly 200 and into the terminal lug second tunnel 112. For power distribution connections utilising the mains cables 1 and associated terminal lugs 100 only, the rear cover portion will typically have no cross-road 20 cable entry apertures. Threaded fastener apertures 207 are provided on the side wall of each of the cover assembly portions 201,202 toward the top thereof and aligned with the second and fifth threaded fastener apertures 113,120 of the terminal lugs 100. An alien key can thus be passed through the apertures 207 in the cover assembly to drive the threaded fasteners 114,121 into engagement with a cable located in the terminal lug 25 second tunnel 112.

Further cable access apertures 208 are provided in the face of the front cover assembly portion 201, and aligned with the third and sixth tunnels 115,125 of the terminal lugs 100 enabling the service or earth cables 12,14 to be passed through the cover assembly and into the third and sixth tunnels 115,125. Again, for power 30 distribution connections utilising two mains cables and two terminal lugs 100, no further cable access apertures are provided in the face or the rear cover assembly portion 202. Further threaded fastener apertures 209 are provided in the side walls of the cover assembly portions 201,202 to again allow access to the threaded fasteners 117,123, 126 [R:\LIBLL]687135nzspeci.doc:GXT 12 and 127 intersecting with the third and sixth tunnels 115,125 so as to drive the fasteners into engagement with cables located in those tunnels.

Where three or four mains cables 1 and associated terminal lugs 100 are being used to form a power distribution connection, alternate forms of the rear cover assembly 5 portion having cable access apertures to suit the connection may be utilised.

There is at times a need to disconnect sections of an electrical power distribution system whilst under electrical load. For example, it may be necessary to disconnect a section of the service side of the system servicing a group of properties to perform some form of maintenance or to install further service cables to that group of properties. 10 Alternatively, it may be necessary to isolate one transformer providing mains electrical power supply to a section of the system, whilst allowing another nearby transformer to provide power to that section. To cater for such disconnection, an alternate form of a cable terminal lug, as depicted in Figure 16 is provided in accordance with a first embodiment of the present invention.

The cable terminal lug 100' is essentially identical to the cable terminal lug 100 of Figures 2 to 4, with the addition of a mounting portion 140, for mounting a link disconnect device, extending from the palm 102 to the second longitudinal end (top) of the cable terminal lug 100'. The cable terminal lug 100' has the same arrangement of tunnels, threaded apertures and fasteners as that of the cable terminal lug 100 of Figures 2 20 to 4, with the omission of the fourth tunnel 124 of the cable terminal lug 100 (which is omitted given the location of the mounting portion 140). The cable terminal lug 100' may also be provided with a fifth tunnel 125 and associated threaded fasteners as per the cable terminal lug of Figures 11 and 12.

The mounting portion 140 is provided with a mounting recess 141 that has an 25 opening 142 extending along the top face of the cable terminal lug 100' and an adjacent lateral side of the mounting portion 140 directly above the face of the palm 102. The recess 141 is defined by a rear wall 143 and first and second opposing side walls 144, 145. The first and second side walls 144,145 are each divided into primary and secondary side wall surfaces 144a, 145a and 144b, 145b. The side wall primary surfaces 30 144a, 145a meet the recess rear wall 143 whilst the side wall secondary surfaces 144b, 145b meet the opening 142 at the lateral side of the mounting portion 140. The opposing primary side wall surfaces 144a, 145a form first and second contact surfaces for engaging first and second conductive portions of a link disconnect device, as will be described below.

[R:\L1BLL]687135nzspeci.doc :GXT 13 The first and second contact surfaces 144a, 145a extend in parallel planes to meet the opening 142 at the longitudinal end face of the cable terminal lug 100'. The parallel planes are parallel to the longitudinal axis of the cable terminal lug 100'.

A link disconnect device suitable for use with the cable terminal lug 100' is 5 disclosed in an Australian Provisional Patent Application filed on 14 July 2005 in the name of Cable Accessories (Australia) Pty Ltd in respect of an "Electrical link disconnect device", the entire contents of which are incorporated herein by cross reference.

An example of such an electrical link disconnect device is depicted in Figures 17 to 19. The electrical disconnect device 201 comprises a non-conductive housing 202, a 10 first conductive portion 203, a second conductive portion 204 and a hinged locking element 205. The conductive elements 203, 204 are in the form of tin plated copper plates. The locking element is operable between a non-locking position, depicted in Figure 19, and a locking position, depicted in Figure 17. In the locking position, the blade portion 213 of the hinged locking element 205 is wedged between the first and 15 second conductive plates 203, 204 forcing them apart. The first and second conductive plates 203, 204 are retained in the housing 202 by way of upper and lower flanges 226, 222. The lower flanges 222 extend only part way along the length of the housing 222, leaving the outwardly facing lower end portions of each of the conductive plates 203, 204 exposed for engagement with the first and second contact surfaces 144a, 145a of the cable 20 terminal lug mounting portion 140, as depicted in Figure 20. The first and second contact surfaces 144a, 145 a are separated by a distance slightly less than the combined thickness of the first and second conductive plates 203,204 and the locking element blade portion 213 of the link disconnect device 201. This provides an interference fit when the link disconnect device 201 is located in the mounting portion recess 141, forcibly engaging 25 the first and second conductive plates 203,204 of the link disconnect device 201 with the first and second contact surfaces 144a, 145 a of the cable terminal lug mounting portion 140, thereby locking the link disconnect device 201 in electrical contact with the cable terminal lug 100'. The secondary side wall surfaces 144b, 145b of the mounting portion 140 are separated by a greater distance than the contact surfaces 144a, 145 a so as to 30 accommodate the lower flanges 222 of the link disconnect device 201, as depicted in Figure 20.

An electrical distribution connection between two cable terminal lugs 100' utilising a link disconnect device 201 is depicted in Figures 21 and 22. The two cable terminal lugs 100' are physically connected utilising an insulated bus bar 150 secured to [R:\LlBLL]687135nzspeci.doc:GXT 14 the palms 102 of the cable terminal lugs 100' by way of a fastener 151 extending through the bus bar mounting apertures 109 of each cable terminal lug 100'. The bus bar 150 thus provides a physical connection, but no electrical connection between the cable terminal lugs 100'.

The link disconnect device 201 is then located so as to extend between the cable terminal lugs 100', specifically located with each longitudinal end portion of the link disconnect device 201 positioned in the mounting recess 141 of the corresponding cable terminal lug 100'. The locking element 205 of the link disconnect device 201 is then forced into the locking position, forcing the first and second conductive plates 203, 204 10 into forced engagement with the first and second contact surfaces 144a, 145a in each of the cable terminal lugs 100'. A secure electrical connection is thus provided between the cable terminal lugs 100'. The cable terminal lugs 100' can be readily electrically disconnected as required by pivoting the locking element 205 to the unlocking position and removing the link disconnect device 201 from the cable terminal lugs 100'. 15 A further alternative form of cable terminal lug 100", according to a second embodiment is depicted in Figure 23. The cable terminal lug 100" is essentially identical to the cable terminal lug 100' of Figure 16 except that the recess 141 of the mounting portion 140 is oriented such that the recess opening 142 opens onto a lateral side of the mounting portion 140 that is located between the faces of the palm 102. That is, the 20 recess 141 is oriented at approximately 90 degrees as compared to the recess 141 of the cable terminal lug 100' of Figure 16.

A still further alternative form of cable terminal lug 100'" according to a third embodiment is depicted in Figure 24. This cable terminal lug 100'" is essentially identical to the cable terminal lug 100" of Figure 23, except that the mounting portion 25 140' is enlarged and is provided with two mounting recesses 141 located side by side.

As depicted in Figures 25 to 27, a three way connection may be established utilising two cable terminal lugs 100" according to Figure 23 and a single cable terminal lug 100"' according to Figure 24. The two cable terminal lugs 100" are physically connected by way of an insulated bus bar 150 in the same manner as described above in 30 relation to Figures 21 and 22. The three cable terminal lugs are interconnected by way of two link disconnect devices 201, each extending between a cable terminal lug 100" and one of the mounting recesses 141 of the cable terminal lug 100'".

A still further alternate form of cable terminal lug 100"" according to a fourth embodiment is depicted in Figure 28. This cable terminal lug 100"" is identical to the [R:\LIB LLJ687135nzspeci.doc:GXT earlier described cable terminal lugs, except that the mounting portion 140" is in the form of a mounting post 147, with opposing parallel walls 148,149 of the post forming first and second contact surfaces for contacting inwardly facing conductive portions of a link disconnect device of the form having a recess, in which the mounting post 147 is received, and inwardly facing conductive portions located on opposing sides of the recess.

Modified forms of cover assembly may be utilised with the cable terminal lugs of Figures 16, 23, 24 and 28. The modified cover assemblies are typically provided with apertures providing access to the mounting portions and link disconnect devices. Removable covers are placed over the apertures.

[R:\LIBLL]687135nzspeci.doc:GXT

Claims (6)

16 The claims defining the invention are as follows:

1. A cable terminal lug comprising: a barrel defining a first tunnel for receipt of a mains cable core strand, said first tunnel opening onto a first longitudinal end of said cable terminal lug; a palm extending from said barrel and defining a generally flat first face; a bus bar mounting aperture extending through said palm generally perpendicular to, and extending through, said first face; a first threaded aperture extending through a wall of said barrel into said first tunnel; a first fastener threadingly received in said first threaded aperture, said first fastener having a leading end extendable into said first tunnel; a second tunnel for receipt of a first cable; a second threaded aperture intersecting said second tunnel; a second fastener threadingly received in said second threaded aperture, said second fastener having a leading end extendable into said second tunnel; and a mounting portion for mounting a link disconnect device, said mounting portion extending from said palm to a second longitudinal end of said cable terminal lug, said mounting portion including a first contact surface for engaging a first conductive portion of a link disconnect device and a second contact surface for engaging a second conductive portion of a link disconnect device.

2. The cable terminal lug of claim 1 wherein said first contact surface and said second contact surface extend in substantially parallel planes to said longitudinal second end of said cable terminal lug, said substantially parallel planes being substantially parallel to a longitudinal axis of said cable terminal lug.

3. The cable terminal lug of either of claims 1 and 2 wherein said first contact surface and said second contact surface are defined on opposing sides of a mounting recess configured to receive the link disconnect device.

4. The cable terminal lug of either of claims 1 and 2 wherein said first contact surface and said second surface are defined on opposing sides of a mounting post configured to be received by the link disconnect device.

5. A power distribution connection comprising: a first cable terminal lug as defined in any one of claims 1 to 4; a second cable terminal lug as defined in any one of claims 1 to 4; and [R:\L1B LLJ687135nzspeci.doc:GXT 17 a link disconnect device having opposing ends thereof mounted on said mounting portion of said first cable terminal lug and said mounting portion of said second cable terminal lug respectively, said link disconnect device having a first conductive portion engaging said first contact surface of each of said first cable terminal lug and said second cable terminal lug and a second conductive surface engaging said second contact surface of each of said first cable terminal lug and said second cable terminal lug.

6. A cable terminal lug substantially as hereinbefore described with reference to any one of Figures 16,23, 24 and 28 of the accompanying drawings. Cable Accessories (Australia) Pty. Ltd. By the Attorneys for the Applicant SPRUSON & FERGUSON Per: [R.\LIBLL]687135nzspeci.doc:GXT