Abstract: A cable for telephone or other communication circuits comprises a number of conductor arrays, specifically pairs or quads of helically intertwined conductors, each conductor having a metal core coated with a thermoplastic sheath in which a multiplicity of short cellulose fibers are embedded; the fibers have an average length of about 1 mm and project generally radially from the sheath over the greater part of their length. The fibers of the twisted wires interpenetrate and form a mat in the intervening spaces which swells in the event of water penetration through a defective envelope, thereby limiting the propagation of moisture along the cable.