Telecommunications cable

• US 5,563,377 A
• Filed: 06/16/1994
• Issued: 10/08/1996
• Est. Priority Date: 03/22/1994
• Status: Expired due to Term

• Current Assignee: Belden Inc.
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Arpin, Benoit, Vexler, Gayriel L.
• Primary Examiner(s): Kincaid, Kristine L.
• Assistant Examiner(s): MACHTINGER, MARC DIAMANT
• Application Number:
  US08/261,073
• Time in Patent Office: 845 Days
• Field of Search: 174/110 PM, 174/110 FC, 174/120 R, 174/120 SR, 174/121 A, 174/113 R
• US Class Current: 174/121.00A
• CPC Class Codes: H01B 7/295 using material resistant to flame

Abstract

A telecommunications cable having a cable core in which each conductor is surrounded by an individual dual layer insulation of an inner layer of flame retardant polyolefin and an outer layer of fluorinated ethylene propylene. The cable is for plenum chamber usage in which smoke is to be minimized. Although the flame retardant polyolefin is a known smoke generating substance which does not satisfy plenum test smoke requirements, its use in this structure is entirely suitable for plenum chamber use because little or no smoke is actually generated as the outer layer protects the inner layer from combustion.

Claims

1. A telecommunications cable having a cable core comprising a plurality of electrical conductors each individually insulated with a dual layer insulation having an inner layer of a flame retardant polyolefin and an outer layer of fluorinated ethylene propylene surrounding the inner layer and wherein the inner layer has a volume of at least 30% of the total volume of the dual layer insulation, the core being provided within a jacket of low smoke generating material.

2. A telecommunications cable having a cable core comprising a plurality of electrical conductors each individually insulated with a dual layer insulation having an inner layer of a flame retardant polyolefin and an outer layer of fluorinated ethylene propylene surrounding the inner layer, the outer layer having a minimum thickness of 2 mil and the core being provided within a jacket of low smoke generating material.