Cables jackets are formed by extruding discontinuities in a main cable jacket portion. The discontinuities allow the jacket to be torn to provide access to the cable core. The discontinuities can be longitudinally extending strips of material in the cable jacket, and can be introduced into the extrudate material flow used to form the main portion through ports in the extrusion head. The discontinuities allow a section of the cable jacket to be pulled away from a remainder of the jacket using a relatively low peel force.