Patent ID: 8294029

Claim:
An expandable electric cord having a structure at least comprised of a core portion, a conductor portion and a sheath portion; wherein, the core portion is an elastic cylinder comprised of an elastic body and an intermediate layer covering the outer periphery thereof, the elastic body is an elastic long fiber having ductility of 100% or more and a converted diameter of 0.01 to 10 mm, or a coil spring having ductility of 50% or more and an outer diameter of 0.02 to 30 mm, the thickness of the intermediate layer is within the range of 0.1 Ld (Ld: converted diameter of the elastic long fiber or outer diameter of the coil spring) or 0.1 mm, whichever is smaller, to 10 mm, the conductor portion contains a conductor wire comprised of narrow stranded wires, with the conductor wire being coiled and/or braided around the outer periphery of the elastic cylinder, and the sheath portion is an outer sheath layer comprised of an insulator that covers the outer periphery of the conductor portion, and the 30% stretch load is 5000 cN or less.