Which standard covers plenums usage for communication cabling?

Which standard covers plenums usage for communication cabling?

• A. All cables may be installed in plenums.
• B. Only non-plenum-rated cables may be installed in plenums.
• C. Plenum-rated cables only may be installed in plenums.
• D. Any cable type may be installed in plenums as long as shielding is adequate.

Answer: (C)

In plenums—the air‑handling spaces of a building—the way a fire behaves is the limiting factor for what cables can be used. Because air moves through these spaces, cables must meet strict fire and smoke safety standards, which is why cables installed there must be plenum-rated. That rating is defined by standards such as UL 910 and is referenced by the NEC for wiring in air‑handling spaces. So only plenum-rated cables may be installed in plenums; using non-plenum cables isn’t allowed due to higher smoke and flame risks, and shielding alone doesn’t substitute for the required rating.

In plenums—the air‑handling spaces of a building—the way a fire behaves is the limiting factor for what cables can be used. Because air moves through these spaces, cables must meet strict fire and smoke safety standards, which is why cables installed there must be plenum-rated. That rating is defined by standards such as UL 910 and is referenced by the NEC for wiring in air‑handling spaces. So only plenum-rated cables may be installed in plenums; using non-plenum cables isn’t allowed due to higher smoke and flame risks, and shielding alone doesn’t substitute for the required rating.