GB2270992A

GB2270992A - Cable containing separable electrical conductors and optical fibres

Info

Publication number: GB2270992A
Application number: GB9216571A
Authority: GB
Inventors: Malcolm Owen Jones; Bryan Davies
Original assignee: Prysmian Cables and Systems Ltd
Current assignee: Prysmian Cables and Systems Ltd
Priority date: 1992-08-04
Filing date: 1992-08-04
Publication date: 1994-03-30
Anticipated expiration: 2012-08-04
Also published as: GB2270992B; GB9216571D0

Abstract

A cable 10 is provided with electrical conductors 11, 12 and optical fibres 13. The conductors 11,12 are provided in one section 15 of the cable and the optical fibres 13 are provided in another section 14 thereof. Each of these sections is surrounded by a respective sheathing means 17, 16. These sheathing means are separably interconnected longitudinally at region 22 so that whilst the optical fibres and electrical conductors are within a single cable and so can be laid in a single cable run, they can be separated from each other along an end portion of the cable to facilitate termination of the conductors and optical fibres at separate termination points. The cable may be armoured (31, 32 Fig. 2). <IMAGE>

Description

CABLES This invention relates to cables.

The use of optical fibre cables to supply services such as telecommunications, television and data transmission is well known and the use of electrical conductor cables to supply electrical power, telecommunications, television and data transmission is also well known.

An object of the present invention is to provide a cable having both electrical conductors and optical fibres whereby only one cable run is required to supply services by both optical fibres and electrical conductors.

The invention provides a cable having electrical conductors and optical fibres, said cable being separable longitudinally into separate sections each surrounded by a respective sheathing means, at least one of the sections having optical fibres therein and at least one other of the sections having electrical conductors therein.

Preferably the or each section having optical fibres therein has no electrical conductors therein, and preferably also the or each section having electrical conductors therein has no optical fibres therein.

A layer of armouring may be provided about the optical fibres and/or electrical conductors in each section inwardly of the sheathing means thereof.

The respective sheathing means may be separably interconnected longitudinally and may be formed from a common extrusion having for example a substantially figure of eight cross-section.

The invention also includes a cable comprising electrical conductors in one section and optical fibres in another section, and an extruded sheath providing first sheathing means surrounding the conductors of said one section and second sheathing means surrounding the fibres of the other section and separably connected to the first sheathing means along the length thereof.

In the preferred embodiments of the invention described hereinafter the electrical conductors are electrical power conductors. These. embodiments are particularly useful for supplying services to domestic premises, since domestic premises have to be supplied with an electrical power service which requires an electrical cable to be run to the premises, and presently services to be supplied to domestic premises via optical fibres require a separate optical fibre cable installion.

In order that the invention may be well understood, two embodiments thereof, which are given by way of example only, will now be described with reference to the accompanying drawings, in which: Figure 1 and 2 are schematic cross-sections of respective cable comprising electrical conductors and optical fibres.

Referring first to Figure 1, there is shown a cable 10 having electrical conductors 11, 12 and optical fibres 13. The cable is separable longitudinally into separate sections 14, 15 each surrounded by a respective sheathing means 16, 17.

The section 14 has optical fibres 13 therein and the section 15 has electrical conductors 11, 12 therein.

In the illustrated embodiment section 14 has no electrical conductors therein and section 15 has no optical fibres therein.

The electrical conductors of section 15 are electrical power conductors. Conductor 11 is a phase conductor for example of stranded copper wire or solid aluminium and is sheathed with a suitably colour-coded insulating layer 18 of plastics material. Conductors 12, which are typically copper wires, are laid up concentrically over the insulating sheath 18 to form a layer thereabout. The conductors 12 act as neutral/earth conductors. A binding 19, for example formed by a layer of polyester tape is provided over the conductors 12. In the other section 14, the optical fibres 13 are provided in respective so-called 'loose tubes' 20. Each tube 20 accommodates at least one and preferably a plurality (for example 2 to 8 fibres) with the fibres being a loose fit in the tube so as to minimise axial strain during cabling and/or installation operations.Alternatively the optical fibres may be present in section 14 in the form of fibre ribbons or single-ruggedised fibres. The fibres may be single or multi-mode. In the illustrated cable, a binding 21 is provided over the tubes 20 to bind them together.

The sheathing means 16, 17 surrounding the sections 14, 15 are separably interconnected along the lengths thereof in the region 22. The sheathing means are formed from a common extrusion of a suitable plastics material such as PVC and as shown this extrusion has a substantially figure of eight crosssection.

As will be appreciated, the cable 10 enables electrical power to be supplied via the electrical conductors and communication services to be supplied via the optical fibres to premises in a single cable run thereto. Furthermore, advantageously, since the sheathing means 16, 17 surrounding each of the cable sections 14, 15 are separable along the region 22 thereof the two sections can be separated at the end portion of the cable thus facilitating termination at separate points within the premises of the electrical conductors and the optical fibres respectively.

As mentioned previously the electrical conductors can be utilised to supply electrical power to the premises and the optical fibres to supply communications services such as telecommunications, television and data transmission. In connection with the latter, it is envisaged that the, or at least some of the, optical fibres can be used to transmit data regarding the usage of electrical power at the premises to a central station to allow automatic metering/billing of the electrical supply.

Referring now to Figure 2, there is shown an alternative cable 30 which is similar in construction to cable 10 but which is provided with armouring.

Parts of the cable 30 corresponding to like parts of the cable 10 have been given like reference numerals.

The construction of the cable 30 differs from that of cable 10 in that respective layers 31, 32 of armouring are provided about the optical fibres 13 in cable section 14 and about the electrical conductors 12 in cable section 15. The layers of armouring 31, 32 are provided inwardly of the sheathing means 16, 17 of the sections 14, 15 and outwardly of respective inner sheaths 33, 34 of these sections. The inner sheaths 33, 34 are preferably formed of the same material as the sheathing means 16, 17.

The armouring 31, 32 may comprise galvanised steel wire, galvanised steel tape, corrugated steel tape or like armouring materials. In certain circumstances it may be desirable only to provide armouring in one of the two cable sections.

Claims

CLAIMS:

1. A cable having electrical conductors and optical fibres, said cable being separable longitudinally into separate sections each surrounded by a respective sheathing means, at least one of the sections having optical fibres therein and at least one other of the sections having electrical conductors therein.

2. A cable as claimed in claim 1, wherein the or each section having optical fibres therein has no electrical conductors therein.

3. A cable as claimed in claim 1 or 2, wherein the or each section having electrical conductors therein has no optical fibres therein.

4. A cable as claimed in any one of the preceding claims wherein a layer of armouring is provided about the optical fibres and/or electrical conductors in each section inwardly of the sheathing means thereof.

5. A cable as claimed in any one of the preceding claims wherein said respective sheathing means are separably interconnected longitudinally.

6. A cable as claimed in claim 5, wherein said separably interconnected sheathing means are formed from a common extrusion.

7. A cable as claimed in claim 6, having two of said sections and wherein said common extrusion has a substantially figure of eight cross-section.

8. A cable comprising electrical conductors in one section and optical fibres in another section, and an extruded sheath providing first sheathing means surrounding the conductors of said one section and second sheathing means surrounding the fibres of the other section and separably connected to the first sheathing means along the length thereof.

9. A cable as claimed in any one of the preceding claims wherein said electrical conductors are electrical power conductors.

10. A cable having electrical conductors and optical fibres, and substantially as herein described with reference to Figure 1 or Figure 2 of the accompanying drawings.