PTFE/Teflon insulation is commonly used for which purpose in cables?

• A. Insulation for plenum-rated cables
• B. Conductor insulation for power cables
• C. Outer jacket for outdoor coax
• D. Fill material for fiber optic cables

Answer: (A)

PTFE insulation is chosen for plenum-rated cables because these cables must meet strict fire and smoke safety requirements in air‑handling spaces. PTFE has excellent electrical insulation properties and, importantly, very low smoke and toxic gas production if it burns. That combination lets cables carry electrical signals safely in plenums without compromising air quality or safety codes, which is why PTFE insulation is the common choice for this use.

The other options don’t fit as well: the outer jacket for outdoor coax is typically a weather- and UV-resistant material, not selected for minimizing smoke in plenums; filler material for fiber optic cables is usually gels, air, or aramid yarn rather than PTFE insulation; and power cables use insulation like XLPE or PVC rather than PTFE, which is more costly and not standard for general power applications.