GB1270732A - Improvements in or relating to the jointing of electric cables - Google Patents

Abstract

1,270,732. Cable joints. PIRELLI GENERAL CABLE WORKS Ltd. 15 April, 1970 [25 April, 1969], No. 21331/69. Heading H2E. A cable joint is encased by a sleeve 8 fitting over a pair of plastics end members 6, 7 cast in situ and hardenable resin 17 is bonded to the adjacent external surfaces of sleeve and end members to seal the joint. For ease in reopening the joint, a release device comprising turns of wire 20 is wound around the surface of the end members prior to sealing as described in Specification 1,270,733. A winding of strong ductile wire may be pulled out to break the seal, or when soft wire is used the seal may be readily broken by hammer blows without damaging the end members. The sleeve may be metal, polyethylene or P.V.C. and in the case of a polyethylene sleeve (or sheath) layers 19 of aluminium foil may be bonded to it as described in Specification 1,087,061. The end members 6,7 are preferably of epoxy resin, and are cast around the cable core using a sleeve the same diameter as sleeve 8 and a cap, pierced by the cable core, at one or both ends of the sleeve (Figs. 2, 3, 4, not shown). These mould members are subsequently removed. The end members may be so formed that the cable sheath terminates within them, i.e. they are also moulded directly on to the cable core, and thus aid in preventing ingress of moisture. Seal 17 is also preferably epoxy resin and is delimited by adhesive tape bands 18. An earth continuity wire 27 may be provided as shown, or it may pass outside sleeve 18 via preformed passages in the end members. For a fluid filled joint a tube passing through an end member may be provided (Fig. 3, not shown), Preferably an epoxy resin primer is applied before and after the application of the release windings and also over aluminium foil 19.