Plenum cable

This invention relates to a communications cable suitable for plenum, riser, and other applications in building structures and, more particularly, relates to an improved construction for such a cable which is capable of meeting burn requirements while at the same time being able to transmit high frequency signals in a local area network. A communications cable having superior electrical characteristics and meeting the burn requirements for plenum applications has a core formed of one or more twisted wire pairs having primary insulation formed of a suitable material, such as high density polyethylene. The core is surrounded by an inner jacket formed of a low smoke, polyvinyl chloride material. As an alternative to or in addition to the inner jacket, the core may be surrounded by a core wrap having adequate electrical properties and burn/flame resistance properties. The inner jacket is surrounded by an outer jacket formed from a material having excellent heat/flame resistance characteristics but which may have less than optimal electrical characteristics, such as a thermoplastic halogenated polymer, for example polyvinylidine fluoride material. A plurality of cores surrounded by individual inner core wraps and/or inner jackets may be surrounded by the outer jacket.