GB870953A - Improvements in or relating to the screening of high-tension electric cables - Google Patents

Abstract

870,953. Cables. PIRELLI S.p.A. March 26, 1959 [July 9, 1958], No. 10579/59. Class 36. A high-tension cable is provided with a screen between the dielectric 5 and the metal element of the cable, i.e. the conductor 1 and/or sheath. The screen consists of two tapings, the first comprising a pair of tapes 2 and 3 of substantially equal thickness S, wound to the same pitch and having mutually interposed convolutions with intervening gaps N, one tape 2 being of conductive material and the other 3 having a conductive layer 3a and an insulating layer 3b, the layer 3a being in contact with the conductor or sheath and the second taping 4 comprising a single tape with a conductive layer 4a and an insulating layer 4b, the layer 4a being in contact with the first taping and the width of the tape being sufficient to cover entirely the conductive tape 2 and the adjacent gaps. Preferably the two tapes 2 and 3 of the first taping are of equal width and the width of tape 4 is equal to twice this plus the width of a gap. The conductive material may be metal, or conductively loaded paper or synthetic material, and the insulating layers may be paper or synthetic material such as polyethylene, polystyrene or polyethyleneterephthalate.