EP1678801A1

EP1678801A1 - Terminal for low voltage electrical cable

Info

Publication number: EP1678801A1
Application number: EP04794943A
Authority: EP
Inventors: Eduardo J. Sanchez De Aparicio
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2003-10-14
Filing date: 2004-10-13
Publication date: 2006-07-12
Also published as: CN1868102A; MXPA03009395A; ECSP066569A; BRPI0415358A; RU2362246C2; WO2005039008A1; RU2006112240A

Abstract

The present invention provides a terminal for minimizing unauthorized use of electricity from a power line while allowing for distribution of electricity to the consumer. The terminal includes a splice closure and a terminal closure. The splice closure has at least two bridging electrical cables and a means for making electrical connection between the power cable and the bridging electrical cable. The terminal closure has at least one bus bar, a neutral terminal block, and means for routing distribution electrical cables out of the terminal closure.

Description

TERMINAL FOR Low VOLTAGE ELECTRICAL CABLE

[0001] The present invention generally relates to terminals for power cables that supply electricity to the consumer. More particularly, the present invention relates to a terminal that isolates and protects a portion of the power cable so as to minimize unauthorized access and unauthorized use of electricity while allowing for the distribution of electricity to consumers.

[0002] Today, in some regions of the world, energy is supplied to the consumer using low voltage electrical cables (i.e., with voltages less than about 1000 volts, typically less than 600 volts). These low voltage electrical cables can be of several types such as: (1) non-insulated conductor cable, i.e., bare copper or bare aluminum wires wound together to form a conductor, (2) simple insulated cable, i.e., the conductor is insulated with a polymeric insulator, such as polyethylene or polyvinyl chloride, and (3) neutral concentric cable, i.e., a polymeric insulation coaxially covers the conductor and a metal shield, such as a copper shield, coaxially covers the insulation. The shield functions as an armor and as a neutral. In this document, for the sake of clarity, such types of electrical cables can be referred to as "power cables", as they supply electrical power to the consumers. The term power cable, however, is not limited to these three specific types of electrical cables. For cost considerations, the low voltage electrical cables may not be buried in the ground but instead are hung in the air from poles or similar structures. In some regions of the world, these cables can carry nominal voltages of 120 volts (phase-ground) or 220 volts (phase-phase). The power cables can carry other nominal voltages but usually will not exceed 1000 volts.

[0003] One advantage of the power cables listed above is that they are cost effective methods of distributing electricity to consumers. One disadvantage is that they are easily accessible so that unauthorized users can divert the electricity without remuneration to the ultililty companies. Although unauthorized diversion of electricity may be more difficult with a simple insulated cable or a neutral concentric cable as compared to a non-insulated cable, such diversion can be done, particularly where such cables are terminated at a transformer. [0004] The diversions in the electricity supply can generate various problems. For example, the unauthorized diversion can cause voltage variations because the number of registered users by phase does not match with the number of actual users. The diversion can also cause overloads leading to blackouts. Short circuits could arise especially where the unauthorized users use low quality connections. There could also be production loss due to blackouts caused by the unauthorized users. The paying customers may have unfairly bear the cost of these problems as the utility companies may need to pass the cost along to them.

[0005] Thus, there exists a need to protect against the unauthorized diversion of electricity in low voltage electrical cables that are of the non-insulated type, of the simple insulated type, and of the neutral concentric type while still allowing for the distribution of electricity to the paying consumers.

Summary

[0006] In one aspect, the present invention pertains to a terminal for a power cable. The terminal comprises (1) a splice closure comprising at least two bridging electrical cables, a first and a second; (2) a terminal closure joined to the splice closure, and (3) a connection device within the splice closure for establishing electrical communication between the bridging electrical cables and the power cable. The terminal closure comprises means for routing distribution electrical cables out of the terminal closure, at least one bus bar, and a neutral terminal block. The first bridging electrical cable is attached to the bus bar and the second bridging electrical cable is attached to the neutral terminal block.

[0007] In another aspect, the present invention pertains to a kit for distributing electricity from a power cable. The kit comprises (1) a terminal comprising a splice closure and a terminal closure, the splice closure comprising at least two bridging electrical cables, the terminal closure comprising at least one bus bar, a neutral terminal block, and means for routing distribution electrical cables out of the terminal closure; (2) means for making electrical connection between the power cable and the bridging electrical cable; and (3) means for securing the terminal to the power cable.

[0008] In yet another aspect, the present invention pertains to a method for distributing electricity from power cables. The method comprising the steps of (1) providing the terminal as recited above; (2) temporarily hanging the terminal from the power cable using cable ties that attach at each end of the terminal to the power cable;

(3) making electrical connections between the power cable and the terminal and between the terminal and distribution electrical cables; (4) securing the terminal to the power cable; and (5) removing the cable ties from the terminal and power cable.

Brief Description of the Drawings

[0009] The invention can be better understood with reference to the following figures, wherein: Figure 1 is a perspective view of one exemplary embodiment of a terminal according to the present invention; Figure 2 is a side view of the terminal in Figure 1 showing the splice closure in an open position; Figure 3 is a side view of the terminal of Figure 1 showing the terminal closure in an open position; and Figure 4 is a perspective view of the terminal of Figure 1 hung on a power line in use.

[0010] These figures are not drawn to scale and are intended merely for illustrative purposes.

Detailed Description

[0011] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments that the invention may be practiced. It is to be understood that other embodiments may be used and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0012] The invention is directed to a terminal that deters and thus minimizes if not eliminates the diversion of electricity from unauthorized users while allowing for the distribution of electricity to legitimate customers. In general, the closure contains a primary subsystem that is attached to a secondary subsystem. The primary subsystem is designed to house a portion of the power cable and contain components therein that allow for the distribution of electricity from the power cable. The secondary subsystems contain the components that allow for the distribution of electricity to the consumer. Both subsystems are designed with means for minimizing and means for detecting unauthorized access into the subsystem. In one aspect, the invention further includes a means for securing the terminal to the power cable. It is within the scope of the present invention that any type of power cable can be used in the present invention, so long as one uses appropriate means for establishing electrical communication between the power cable and the bridging cable in the closure terminal, as better explained herein.

[0013] Figure 1 shows one exemplary embodiment of the invention. Terminal 10 comprises integral splice closure 12 and terminal closure 14. Terminal 10 may be adapted to be suspended from an aerial power cable (not shown). In one embodiment, the terminal resists impact. Because the terminal is typically hung in the air, it should be stable when subjected to long and repeated exposure to ultraviolet light. In one embodiment, the terminal meets the requirements of Underwriter's Laboratory (UL) 746D Polymeric Materials Fabricated Parts.

[0014] Splice closure 12 comprises casing 20 that may be opened along an edge or opening seal 21. The seam has mating ridges and grooves to form a labyrinth type seal for restricting the ingress of dirt, water, bugs, and the like, into casing 20. Casing 20 comprises first and second casing sections 22 and 24 respectively. In one embodiment, hinge line 26 is defined by a compression-molded hinge 28 so that hinge 28 is integral with casing sections 22 and 24. In one embodiment, casing 20 is molded from a suitable polymer material, such as polyethylene or the like. Casing 20 may be made by any conventional molding technique, such as blow molding, injection molding, and the like. Each section 22, 24 is approximately one half of casing 20, so that each section is substantially semi-cylindrical in configuration.

[0015] Casing 20 has first and second opposite ends 30, 32. End seals 34 (refer to Figure 2) are disposed at first and second ends 30, 32 for receiving and sealing around the power cables (not shown) entering and exiting the casing at first and second ends 30, 32. The casing is maintained and secured in a closed condition by latch or fastening device 40. Fastening device 40 may be any of a variety of conventional arrangement where section 22 may be selectively secured to section 24 along seam 21.

[0016] As will be apparent by examination of Figure 1, access to the enclosed splice area within casing 20 is facilitated by the rotational position of first casing section 22 (in the upper position) relative to second casing section 24 (in the lower position). In particular, first and second sections 22, 24 of casing 20 are oriented such that when casing 20 is opened, a substantially unobstructed view is provided into the splice area inside casing 20. This is accomplished by preferred positioning of hinge line 26 relative to the location of hangers 16. In one embodiment, hinge line 26 is positioned between 125° to 145°, and preferably about 135°, from attachment points of hangers 16 for mounting the terminal 10 to a support cable (not shown).

[0017] In Figure 2, splice closure 12 is depicted with casing 20 in the open position. End seals 34, which may be formed according U.S. Patent No. 4,857,672, assigned to assignee of this application, are supported in recesses in first and second ends 30, 32 of section 22 such that end seals 34, upon receiving a cable there through, are retained adjacent first and second ends 30, 32, respectively. End seals 34 are engaged and sealed by cooperating recessed areas at the first and second ends 30, 32 of section 24 when the sections 22, 24 are in the closed position. [0018] Section 24 of casing 20 includes openings 42 that form drains in the lower portion of casing 20. Openings 42 may be screen covered and include filtering means to limit the ingress of dirt, water, bugs, and the like, into casing 20.

[0019] Casing 20 also includes a support surface 50 for joining to and supporting terminal closure 14. Support surface 50 is generally flat and is positioned to be located on a side of casing 20 below opening seam 21, such that the terminal closure 14 supported thereon is readily accessible from the side or front of terminal 10. Splice closure 12 further includes the fastening device 40, and in the embodiment of Figure 2 fastening device 40 is supported on section 22 of casing 20 such that the latch portion of fastening device 40 may engage a boss 56 on section 24 above support surface 50. Adjacent opening seam 21 in the outer wall of casing 20 is projections 62 with concave portions defining recesses 64. As better explained below, recesses 64 are formed for securing lid 78 of terminal closure 14 when it is desired to have access to the interior of terminal closure 14.

[0020] On support surface 50 in splice closure 12 is attached at least one bridging electrical cable 116. The bolts shown on support surface 50 are preferable insulated with a mastic or with a polymeric material, e.g., polyvinyl chloride. Although four bridging electrical cables are shown, any other numbers can be used. The bridging cables can be equipped with an insulation piercing connectors (IPC, not shown) for electrical connection between the bridging cables with the power line (not shown). Similarly, when a separate neutral is present with the power cable, the IPC can be used to put it in electrical communication with one of the bridging cable. In one embodiment, the IPC can fabricated from aluminum-copper allow or tin plated copper and can be insulated. The IPC preferably has a lubricating compound to maximize the probability of having a proper electrical connection between the cables and the IPC and to minimize corrosion. The LPC can be designed for a wire range of about 13 mm² to

68 mm² (6 AWG to 2/0 AWG).

[0021] Optionally, the exposed end of the bridging electrical cables can be protected against the elements with an end cap. Although the bridging electrical cables are secured in the splice enclosure, which are typically closed, the end cap provides additional protection for them. The bridging electrical cables should be selected so as to be compatible with the nominal voltage of the power cable.

[0022] With reference to Figure 3, terminal closure 14 is joined to casing 20 at the support surface 50 by any suitable means to make splice closure 12 and terminal closure 14 a unitary structure. If splice closure 12 and terminal closure 14 are first formed as separate units, suitable means for making splice closure 12 and terminal closure 14 a unitary structure include, e.g., joining splice closure 12 and terminal closure 14 using pop rivets, machine screws, bolts, heat welding, sonic welding, and the like. Splice closure 12 and terminal closure 14 may alternately be joined to form a unitary structure by molding the closures 12, 14 together as a single structure, rather than first forming them as separate units.

[0023] The support surface 50 is positioned to place terminal closure 14 on a side of casing 20 when terminal 10 is suspended from a power cable (not shown). Terminal closure 14 comprises a top wall 70, a bottom wall 72, end walls 74, 75, back wall 76 and a lid 78. Lid 78 is hinged to top wall 70 of terminal closure 14 and in one embodiment, is hinged by a compression-molded hinge 80. That is, hinge 80 is integral with top wall 70 and lid 78 of terminal closure 14. The terminal closure 14 may be molded from a suitable polymer material, such as polyethylene or the like. In this manner, hinge 80 can be readily formed integrally with the walls and lid of terminal closure 14 when molded. Terminal closure 14 may be formed by any conventional molding technique, such as by blow molding, injection molding, and the like.

[0024] Lid 78 is provided with a locking mechanism 90, intended to deter and to minimize unauthorized access into terminal closure 14. Lid 78 is also provided with detents 81 on its outer surface adjacent hinge 80. Detents 81 cooperate with recesses 64 in casing 20 to maintain lid 78 in an open and raised position when lid 78 is raised sufficiently by, for example, a service technician worlcing on the contents of terminal closure 14. The flexibility of the polymer material forming splice closure 12 and terminal closure 14 is sufficient to permit detent 81 to enter recesses 64 and thereby secure lid 78 in the raised open position. Lid 78 and bottom wall 72 have cooperating latches 82, 84 to hold lid 78 in a closed position. Locking mechanism 90 is disposed on lid 78 to deter and thereby minimize unauthorized access into the terminal closure. The locking mechanism can be specially keyed and cooperates with mating part 102 (in Figure 3). Optionally, a security tape can be used to seal the terminal closure. The security tape can be attached to lid 78 of and at least one of the bottom wall 72 and end walls 74, 75 of the terminal closure. When unauthorized access into the terminal closure occurs, the tape will visually indicate such access. For example, the word "void" may appear on the tape once it has been broken. The security tape can be replaced with new security tape when unauthorized access has occurred. The advantage of the security tape and locking mechanism 90 is that they deter unauthorized access into the terminal closure but yet still record such access if it occurred.

[0025] The bridging electrical cables 116 that originate from splice closure 12 are terminated to connector 114 of bus bar 110 of terminal closure 14. Mechanical fastening means, such a bolt or a screw 112, can be used to fasten the bus bar into the terminal closure. Other means to attach the bus bar can be used. In one embodiment, the fastening means is insulated. The bus bar can be insulated or non-insulated. They can be attached directly terminal closure 14 as shown in Figure 3. Alternatively, they can be attached to a device that is attached to terminal closure 14 so as to provide an air gap between the bus bar and the terminal closure. In yet another alternatively, an insulating tape is first applied to the non-insulated bus bar which then is adhered to the terminal closure. Suitable tapes include, e.g., polyvinyl chloride used in conjunction with mastic.

[0026] Bus bar 110 includes a plurality of ports 118 for attachment of distribution electrical cables (not shown). In one embodiment, the bus bars are classified for outdoor applications and the materials used in fabricating the bus bars are aluminum- copper alloys or tin plated copper according to ASTM B 454 and has a wire range of about 2 mm² to 54 mm² (12 AWG to 1/0 AWG). In the embodiment of Figure 3, three bus bars, each having six ports, are shown. Other number of bus bars having different number of ports can be used in the practice of the present invention. One of the bridging electrical cables is connected to neutral terminal block 104 that includes a plurality of ports 108. The distribution electrical cables that emanate from bus bars 110 or neutral terminal block 104 exit terminal closure 14 through openings 122, which initially contain perforations and are punched out to create the openings only when a distribution electrical cable needs to be routed out of the terminal closure. In one embodiment, the neutral terminal block is classified for outdoor applications and the materials used in fabricating the bus bars are aluminum-copper alloys or tin plated copper according to ASTM B 454 and has a wire range of about 3 mm² to 54 mm² (10 AWG to 1/0 AWG).

[0027] Now turning to Figure 4, there is shown the embodiment of Figure 1 hung aerially from a power cable that has been attached to a pole. Terminal 150 is hung on power cable 151, which includes three incoming electrical cables 152 and, in this particular situation, non-insulated neutral line 154. Preferably, the terminal is attached to the power line some distance away from the pole so as to limit its access by unauthorized users. In this particular application, a tape like material (not shown) is used to secure terminal 150 to power cable 151. The tape like material can be wrapped around first and second ends 30, 32 of casing 20 (see Figure 1) and the power cable to attach the terminal to the power cable. An exemplary tape like material is 3M™ 4560 Armorcast™ Material available from 3M Company, St. Paul, Minnesota. The Armorcast™ Material is a structural material. In general, it is a flexible fiberglass knit fabric strip saturated with a curable resin and is air cured in duration of time, about 20 minutes. The power line enters the spice enclosure of the terminal where individual electrical cables 152 are tapped. The electricity is then distributed in the terminal closure via distribution electrical lines 156. Distribution electrical lines 156 emanate from the terminal closure and are directed to the consumer's dwelling, e.g., a circuit breaker box in the dwelling.

[0028] The present invention can be used with non-insulated power cables. In such application, an effective approach to deterring the unauthorized use of electricity would involve retrofitting a portion of the non-insulated line with an insulation tape. A suitable tape is commercially available from 3M Company, St. Paul, Minnesota under product designation 3M™ 27 Glass Cloth Electrical Tape. Other tapes can be used. The terminal is hung a sufficiently long distance away from an electrical pole. The non-insulated cable between the terminal and the pole is insulated. The terminal would be attached to the non-insulated power cable as described above.

Claims

What is claimed is:

1. A terminal (10) for a power cable (151), the terminal comprising: a splice closure (12) comprising at least two bridging electrical cables (116), a first and a second; a terminal closure (14) joined to the splice closure (12) , the terminal closure (14) comprising means for routing distribution electrical cables (156) out of the terminal closure (14), at least one bus bar (110), and a neutral terminal block (104), wherein the first bridging electrical cable is attached to the bus bar (110) and the second bridging electrical cable is attached to the neutral terminal block (104); and a connection device within the splice closure (12) for establishing electrical communication between the bridging electrical cables (116) and the power cable (151).

2. The terminal of claim 1, wherein the connection device is an insulation piercing connector.

3. The terminal of claim 1, wherein the bus bar is insulated with a coating of polymeric material.

4. The terminal of claim 1, wherein the at least one bus bar (110) and the neutral terminal block (104) comprises a connector (114) or making electrical connection between the bridging electrical cable (116) and the at least one bus bar (110) and the neutral terminal block (104); and at least one port (108) for mounting distribution electrical wires (156).

5. The terminal of claim 1 further comprising a means for locking (90,102) the terminal closure.

6. The terminal of claim 1 further comprising a security tape disposed on a lid and on at least one of the bottom wall and end wall of the terminal closure.

7. The terminal of claim 1, wherein the bridging electrical cable in the splice enclosure has an exposed end that is protected by an end-cap.

8. The terminal of claim 1 attached aerially to the power cable.

9. The terminal of claim 8, wherein a flexible fiberglass knit fabric saturated with a curable resin secures the terminal to the power cable.

10. A kit for distributing electricity from a power cable, the kit comprising: a terminal (10) comprising a splice closure (12) and a terminal closure (14), the splice closure (12) comprising at least two bridging electrical cables (116), the terminal closure comprising at least one bus bar (110), a neutral terminal block (104) , and means for routing distribution electrical cables out of the terminal closure; means for making electrical connection between the power cable and the bridging electrical cable; and means for securing the terminal to the power cable.

11. The kit of claim 10, wherein the means for making electrical connection between the low voltage supply electrical cable and the bridging electrical cable comprises an insulating piercing connector.

12. The kit of claim 10, wherein the means for securing the terminal to the power cable comprises a flexible fiberglass knit fabric saturated with a curable resin.

13. The kit of claim 10, wherein in the terminal closure, the first bridging electrical cable is attached to the bus bar and the second bridging electrical cable is attached to the neutral terminal block.

14. The kit of claim 13, wherein the at least one bus bar and the neutral terminal block comprises a connector for making electrical connection between the bridging electrical cable and the at least one bus bar and the neutral terminal block; and at least one port for mounting distribution electrical wires.

15. The kit of claim 10 further comprising security tape for attaching on a lid and on at least one of the bottom wall and end wall of the terminal closure.

16. A method for distributing electricity from power cables, the method comprising the steps of: providing the terminal of claim 1, temporarily hanging the terminal from the power cable using cable ties that attach at each end of the terminal to the power cable; making electrical connections between the power cable and the terminal and between the terminal and distribution electrical cables; securing the terminal to the power cable; and removing the cable ties from the terminal and power cable.

17. The method of claim 1 wherein the securing the terminal to the power cable comprises using a flexible fiberglass knit fabric saturated with a curable resin.

18. The method of claim 1 wherein the terminal comprises means for locking the terminal closure to minimize unauthorized access therein and the method further comprises applying a security tape to a lid and at least one bottom or at least one end wall of the terminal closure.