US Patent 7560646 Profiled insulation and method for making the same

A wire has a conductor and an insulation extruded onto the conductor. The insulation has a plurality of alternating crests and crevasses, where the ratio of the distance from the conductor to a top of the crest to the distance from the conductor to a lowest point in the adjacent crevasse is at least 1.1 and where the ratio is sustained within a tolerance variation of not more than 15% along the length of the wire.