GB1012097A - Multiconductor plastic insulated telephone cables - Google Patents

Abstract

1,012,097. Electric cables. STANDARD TELEPHONES & CABLES Ltd. Jan. 10, 1963, No. 1218/63. Heading H1A. A multi-conductor telephone cable comprising a number of pairs each consisting of two conductors 1, 2 (Fig. 3) embedded in and separated by a web of plastics insulation is constructed in such a way that the total amount of insulation required for each conductor pair in the cable is less than that required for each conductor pair in a cable having conventional pairs (Fig. 1, not shown) and having the same mutual capacitance. The web of each pair is of such a length and thickness that the lower mutual capacitance it provides directly between the conductors of the pair as compared with that directly between the conductors of conventional pair having concentric insulation compensates for the increase in mutual capacitance due to neighbouring pairs and an earthing screen, if one is is provided, which increase arises from the decrease in thickness of the insulation surrounding the conductors. The pairs which are individually twisted may be bunched or stranded together and enclosed within a helical winding of plastics material 3 (Fig. 4) and an outer covering 4. Fins may be included in the shape of the insulation to space the pairs apart and the thickness of the web is chosen to be in accordance with mechanical and extrusion requirements.