GB2201847A

GB2201847A - Joining extruded cable to impregnated lapped cable

Info

Publication number: GB2201847A
Application number: GB08803410A
Authority: GB
Inventors: Miguel Angel Rivero Ortiz; Carmine Taralli
Original assignee: Pirelli SA Compania Industrial Brasileira
Current assignee: Pirelli SA Compania Industrial Brasileira
Priority date: 1987-02-16
Filing date: 1988-02-15
Publication date: 1988-09-07
Anticipated expiration: 2008-02-15
Also published as: GB2201847B; AR241350A1; GB8803410D0; BR8701026A

Abstract

A metal sheathed cable A with impregnated lapped insulation is connected to a cable B having extruded insulation by fitting C comprising an elongate conductor disposed within a moulded insulating body 9, extending from one end 9a of the body 9 and being connected end-to-end with the conductor 1 of the cable A. The other end 9b of the fitting C is formed with a coupling part which is coupled to a coupling D of the cable B. An annular flange 14 extends radially outwardly of the body 9 of the fitting C and forms a closure of an open end of an elongate metal casing 13 which surrounds the end-to-end connection. The other end 13b of the casing is sealingly joined to the metal sheath 5 of the cable A. <IMAGE>

Description

CABLE JOINTING This invention relates to cable jointing and in particular connecting a metal sheathed cable provided with impregnated lapped insulation to a cable provided with extruded insulation.

To facilitate the connection of such cables, the present invention provides a fitting comprising an elongate conductor disposed within a moulded insulating body, one end of the fitting being formed with a male or female coupling part for coupling said fitting conductor with a female or male coupling of a cable provided with extruded insulation, said fitting conductor extending from the body at the other end of the fitting for connection end-to-end with a conductor of the metal sheathed cable, and an annular flange extending radially outwardly of the body for forming a closure for an open end of an elongate metal casing which is adapted to surround said end-to-end connection and be sealingly joined at its other end to the metal sheath of the cable provided with impregnated lapped insulation.

Preferably the moulded body has a substantially frusto-conical outer surface between the flange and said other end of the fitting, the diameter of said outer surface decreasing in a direction away from the flange.

The invention also includes a metal sheathed cable provided with impregnated lapped insulation which is fitted with a fitting as defined above, the conductor of the cable being connected end-to-end with the conductor of the fitting, and having an elongate metal casing surrounding the end-to-end connection, one end of the casing being sealingly joined to the metal sheath of the cable and the other end being sealingly connected to the flange of the fitting.

Preferably, insulating compound is provided within the casing.

The invention also includes an arrangement comprising a metal sheathed cable as defined above and a cable provided with extruded insulation, wherein the latter cable is provided with a female or male coupling which is coupled to the male or female coupling part of the fitting fitted to the metal sheathed cable whereby said cables are interconnected.

Preferably in an arrangement as defined above, the coupling of the cable provided with extruded insulation is releasably maintained in coupling engagement with the coupling part of the fitting by means comprising tie rods extending between the fitting flange and the coupling of the couple provided with extruded insulation.

The invention also includes a metal sheathed cable as defined above connected with at least two cables provided with extruded insulation, wherein each of said at least two cables is coupled at one end to a junction unit so as to be electrically connected to a coupling length of cable provided with extruded insulation which coupling is also coupled at one end to the junction unit, the other end of said coupling length being coupled to the coupling part of the fitting fitted to the metal sheathed cable.

In the arrangement defined in the last preceding paragraph, the junction unit may comprise a male or female coupling which is releasably coupled to a female or male coupling at said one end of said coupling length and at least two further male or female couplings, which are respectively releasably coupled to a female or male coupling at an end of each of said at least two cables.

The invention also includes a method of connecting a metal sheathed cable provided with impregnated lapped insulation to a cable provided with extruded insulation, which method comprises fitting a fitting as defined above to the metal sheathed cable such that the fitting conductor is connected end-toend with the conductor of the metal sheathed cable, surrounding said end-to-end connection with an elongate metal casing, sealingly joining one end of said casing to the metal sheath of the metal sheathed cable and sealingly connecting the other end of said casing to the flange of the fitting.

In order that the invention may be well understood, some embodiments thereof, which are given by way of example only, will now be described with reference to the accompanying drawings, in which: Figure 1 is a part-fragmentary and part-axial cross-sectional view illustrating an arrangement comprising a metal sheathed cable provided with impregnated lapped insulation connected with a cable provided with extruded insulation; Figure 2 illustrates an arrangement, wherein a metal sheathed cable provided with impregnated lapped insulation is connected with two cables provided with extruded insulation; and Figure 3 illustrates an arrangement, wherein a metal sheathed cable provided with impregnated lapped insulation is connected with three cables provided with extruded insulation Referring first to the arrangement shown in Figure 1, a single core, metal sheathed cable provided with impregnated lapped insulation and generally ixldicated by A is connected to a single core cable B provided with polymeric extruded insulation. This connection is achieved using a fitting C which is fitted to the end of the metal sheathed cable C and which is formed with a coupling part which is coupled to a coupling D provided on the cable B.

In more detail, the cable A comprises a central conductor 1, a semi-conducting screen 2 over the conductor, impregnated lapped paper insulation 3 over the screen 2, a semi-conducting screen 4 over the lapped insulation, a metal sheath 5 over the screen 4, and a further protective sheath 20 over the metal sheath. The end of the cable A is stripped back over successive increasing lengths to its conductor 1, screen 2, lapped insulation 3, screen 4, and metal sheath 5 as illustrated in Figure 1. Further, the lapped insulation 3 is stripped over the end portion thereof to present a substantially frusto-conical outer surface 6 tapering from the outer surface of the insulation 3 down to the outer surface of the screen 2.

The fitting C comprises a moulded insulating body 9 formed of an epoxy resin, within which an elongate conductor is disposed. The fitting conductor extends from the body 9 at the end 9a thereof and is connected end-to-end with the conductor 1 of the cable A for example by a compression ferrule 7 as illustrated or by welding.

The moulded body 9 has a substantially frustoconical outer surface between an annular metal flange 14 which extends radially outwardly of the body, and its end 9a, the diameter of the outer surface decreasing in a direction away from the flange.

Semi-conducting tape 8 is wound onto the fitting conductor extending from the end 9a of the body 9 to form a layer over the conductor having the same thickness as the screen 2 over the conductor 1 of cable A.

Layers 10 of insulation formed from insulating tape, for example paper insulating tape, are provided over the end-to-end connection of the fitting and cable conductors and extend axially over the lapped insulation 3 of cable A and the insulating body 9 of fitting C as illustrated in Figure 1. The layers 10 of insulating tape are then covered by a layer of semi-conductive tape and a copper mesh 11 which is connected to the metal sheath 5 of the cable A.

The thus formed joint between the conductors of the cable A and the fitting C is surrounded by an elongate metal casing 13. The flange 14 of the fitting C forms a closure for an open end 13a of the casing which open end is sealingly connected to the flange by suitable metal fastening trim or clamping means. The other end 13b of the casing is sealingly joined to the metal sheath 5 of cable A for example by being plumbed thereto. It will be appreciated that the casing would be slid onto cable A and along the length thereof away from the illustrated end prior to the conductors of the cable A and fitting C being connected end-to-end and subsequently slid back over the end to the position illustrated in Figure 1. The space 12 remaining within the casing 13 is filled with insulating compound which is compatible with the insulating compound used to impregnate the insulation 3.It will be appreciated that a leak proof assembly is achieved by the sealing connection of the casing 13 to the sheath 5 and to the flange 14.

The fitting C is formed at its end 9b with a coupling part for coupling the conductor of the fitting with the coupling D provided on cable B to connect the conductor of that cable to the fitting conductor. As illustrated the coupling part of the fitting C is a male coupling part and the coupling D is a female coupling part. However it is to be understood that the coupling part could be a female coupling part and the coupling D could be a male coupling part. Further it is to be understood that the male coupling part may merely comprise an end portion of the fitting conductor extending from the body 9.

The coupling D is releasably maintained in coupling engagement with the coupling part of the fitting C by means comprising tie rods 16 extending between the flange 14 of the fitting and an annular ring 16a located on the coupling D in engagement with a shoulder 15a formed on a flange extending radially outwardly of a rubber insulating body 15 of the coupling D.

Figures 2 and 3 respectively illustrate arrangements in which the metal sheathed cable A is connected with two and three cables B provided with extruded insulation. In each of these arrangements, each of the cables B is coupled at one end to a junction unit so as to be electrically connected to a coupling length E of cable provided with extruded insulation which coupling length is also coupled at one end to the junction unit. The other end of the coupling length E is coupled to the coupling part of a fitting C fitted to the metal sheathed cable A in the manner of the arrangement shown in Figure 1.

The junction unit 18 shown in Figure 2 comprises a male coupling 18a which is releasably coupled to a female coupling F provided at the end of the coupling length E which is coupled to the cable A. The unit 18 additionally comprises two further male couplings 18b which are respectively releasably coupled to female couplings G and H coupled to the ends of the cables B.

The coupling G may be identical to coupling D previously described and be provided with a rubber insulating body 15. The couplings F and H however are formed with rubber insulating bodies 17 forming 900 elbows to allow the cable B and cable length E attached thereto to run perpendicularly to the cable B provided with the coupling G. As will be appreciated the male coupling 18a is electrically connected to the male couplings 18b within the unit 18 and the unit 18 is provided with suitable insulation.

It will also be understood that whilst the unit has been provided with male couplings it may be provided with female couplings for coupling with male couplings provided on the cables B and cable length E.

The junction unit illustrated in Figure 3 comprises one coupling 19a which is releasably coupled to the coupling F of the coupling length E and three further couplings 19b which are respectively coupled to the couplings at the ends of the cables B. As illustrated these couplings comprise two couplings G and one coupling H. The arrangement shown in Figure 3 is otherwise as the arrangement shown in Figure 2 and like references have been used in these two figures to indicate like parts.

Claims

CLAIMS:

1. A fitting for use in connecting a metal sheathed cable provided with impregnated lapped insulation to a cable provided with extruded insulation, said fitting comprising an elongate conductor disposed within a moulded insulating body, one end of the fitting being formed with a -male or female coupling part for coupling said fitting conductor with a female or male coupling of a cable provided with extruded insulation, said fitting conductor extending from the body at the other end of the fitting for connection end-to-end with a conductor of the metal sheathed cable, and an annular flange extending radially outwardly of the body for forming a closure for an open end of an elongate metal casing which is adapted to surround said end-to-end connection and be sealingly joined at its other end to the metal sheath of the cable provided with impregnated lapped insulation.

2. A fitting as claimed in claim 1 wherein said moulded body has a substantially frusto-conical outer surface between the flange and said other end of the fitting, the diameter of said outer surface decreasing in a direction away from the flange.

3. A metal sheathed cable provided with impregnated lapped insulation which is fitted with a fitting as claimed in claim 1 or 2, the conductor of the cable being connected end-to-end with the conductor of the fitting, and having an elongate metal casing surrounding the end-to-end connection, one end of the casing being sealingly joined to the metal sheath of the cable and the other end being sealingly connected to the flange of the fitting.

4. A cable as claimed in claim 3, wherein insulating compound is provided within said casing.

5. An arrangement comprising a metal sheathed cable as claimed in claim 3 or 4 and a cable provided with extruded insulation, wherein the latter cable is provided with a female or male coupling which is coupled to the male or female coupling part of the fitting fitted to the metal sheathed cable whereby said cables are interconnected.

6. An arrangement as claimed in claim 5, wherein the coupling of the cable provided with extruded insulation is releasably maintained in coupling engagement with the coupling part of the fitting by means comprising tie rods extending between the fitting flange and the coupling of the cable provided with extruded insulation.

7. An arrangement comprising a metal sheathed cable as claimed in claim 3 or 4, connected with at least two cables provided with extruded insulation, wherein each of said at least two cables is coupled at one end to a junction unit so as to be electrically connected to a coupling length of cable provided with extruded insulation which coupling length is also coupled at one end to the junction unit, the other end of said coupling length being coupled to the coupling part of the fitting fitted to the metal sheathed cable.

8. An arrangement as claimed in claim 7, wherein said junction unit comprises a male or female coupling which is releasably coupled to a female or male coupling at said one end of said coupling length and at least two further male or female couplings, which are respectively releasably coupled to a female or male coupling at an end of earth of said at least two cables.

9. A method of connecting a metal sheathed cable provided with impregnated lapped insulation to a cable provided with extruded insulation, which method comprises fitting a fitting as claimed in claim 1 or 2 to the metal sheathed cable such that the fitting conductor is connected end-to-end with the conductor of the metal sheathed cable, surrounding said end-toend connection with an elongate metal casing, sealingly joining one end of said casing to the metal sheath of the metal sheathed cable and sealingly connecting the other end of said casing to the flange of the fitting.

10. A fitting for use in connecting a metal sheathed cable provided with impregnated lapped insulation to a cable provided with extruded insulation substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

11. A metal sheathed cable fitted with a fitting as claimed in claim 10 substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

12. An arrangement comprising a metal sheathed cable provided with impregnated lapped insulation connected to at least one cable provided with extruded insulation substantially as hereinbefore described with reference to the accompanying drawings.

13. A method of connecting a metal sheathed cable provided with impregnated lapped insulation connected to at least one cable provided with extruded insulation substantially as hereinbefore described with reference to the accompanying drawings.