Both twisted-pair and coaxial are made in plenum versions. Most plenum cable and plenum wire products are covered with PTFE or PVC.

Plenum products, including Plenum cable and Plenum wire, are coated with a flame-retardant material, usually PTFE Non-Stick Resin, so that in the event of a fire, it will not emit toxic fumes and smoke as it burns. In some areas of the world, plenum wire is required by law. Because of these requirements, plenum wire and plenum cable tend to be more expensive than non-plenum wire and cable. Plenum wire is also stiff and therefore more difficult to work with than non-plenum products.

In building construction, the plenum space is the area that is used for air circulation of heating and air conditioning systems, usually located between the structural and suspended ceiling or under a raised floor. Plenum Space is where Plenum Wire is installed.

Plenum Wire and Plenum Cable are wire and cable products that can legally be installed in the plenum spaces of a building, typically, the area used to store a building’s communication cables, both for the computer and telephone network.