Patent 7105749 was granted and assigned to Pirelli on September, 2006 by the United States Patent and Trademark Office.
An electric cable for power transmission at low voltage has at least one conductor and an insulating coating surrounding the at least one conductor. The insulating coating has at least two insulating layers. In a radial direction from the inside toward the outside of the electrical cable, the insulating coating has at least one insulating layer made of a non-expanded polymeric material and at least one insulating layer made of an expanded polymeric material.