Patent ID: 7084348

Claim:
A communications cable having minimized smoke generation and flame spread, comprising: a low-smoke PVC jacket defining a core region for housing a plurality of electrical conductors; a plurality of twisted pair conductors disposed within said jacket at said core region; said twisted pair conductors having an electrically conductive metal center and an insulation layer overlying and contacting said metal center; said insulation layer of all of said plurality of said twisted pair conductors being formed of a polyolefin selected from the group consisting of polyethylene and polypropylene, and combinations thereof; said insulation layer further including a flame retardant; and wherein said insulation layer is substantially free of fluoropolymer and said core region contains substantially no fluoropolymer; and wherein said insulation layer has an inner region contacting said electrically conductive metal center, a middle region overlying said inner region and an outer region overlying said middle region: said inner region being formed of a polyolefin selected from the group consisting of solid polyolefins and foamed polyolefins; said middle region being formed of foamed polyethylene; said outer region being formed of unfoamed polypropylene modified to increase fire resistance wherein said outer region has a radial thickness of from about 0.0015 to about 0.005 inch, said middle region has a radial thickness of up to about 0.004 inch and said inner layer has a radial thickness of up to about 0.004 inch, and wherein polyethylene forms from about 15% by weight to about 35% by weight of said insulation layer and polypropylene forms from about 65% by weight to about 85% by weight of said insulation layer.