Flame retardant inside wiring cable made with an annealed metal sheath
AssigneeGeneral Cable Corporation
InventorWilliam J. Brorein
Life of this patent
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Abstract
This inside wiring cable has insulated conductors surrounded by one or more layers of heat-resistant tape covered by a protective metal sheath which is preferably made of longitudinally folded metal strip with the seam welded and the tube metal then reduced in diameter down into intimate contact with the core and annealed. The cable is fire-resistant so that it does not spread fire. The metal sheath prevents any "afterburn."
Claims14
An electrical cable for use as fire-resistant, low voltage communication and signal circuits inside of buildings including in combination a cable core having a multitude of electrical conductors that are individually insulated by a surrounding layer of insulation material, each insulated conductor being crowded together in contact with other insulated conductors of said core, the insulation including inorganic material to reduce flammability of the cable core, said conductors being bunched together in the core with individual conductors located at various and random distances from the outside limits of the core, said core having a heat barrier layer surrounding the bunched conductors and of a thickness substantially less than the radius of the bunch of conductors comprising the core, and an annealed flexible metallic sheath fitting snugly around the core over the heat barrier layer for protecting the core from flames in the vicinity of the cable, said metallic sheath constituting the outermost layer of said cable.
An assembly of electrical cables for use as fire-resistant, low voltage communication and signal circuits inside of buildings including in combination a plurality of first cables each comprising a cable core having a multitude of electrical conductors that are individually insulated by a surrounding layer of insulation material, the insulation including inorganic material to reduce flammability of the cable core, said conductors being bunched together into a core with individual conductors located at various and random distances from the outside limits of the core, said core having a heat barrier layer surrounding the bunched conductors and of a thickness substantially less than the radius of the bunch of conductors, and an annealed flexible metallic sheath fitting snugly around the core over the heat barrier layer for protecting the core from flames in the vicinity of the cable, said metallic sheath constituting the outermost layer of said cable and a plurality of second structurally independent wiring cables each of similar construction to said first cables but with plastic outer protective jackets substituted for the metallic sheaths of the first cables, the cables with the plastic jackets being adjacent to the cables with the metallic sheaths, so that the metallic sheaths serve as heat shields for adjacent cables having the plastic outer jackets in the event that the assembly is exposed to flames.
Dependencies are inferred from the claim text.