CompTIA Network+ (N10-009)Network ImplementationEasy
A technician needs to run network cabling through the space above a drop ceiling that is also used as a return-air path for the building's HVAC system. Which type of cable MUST be used in this space to comply with fire code?
- ADirect burial cable
- BPVC-jacketed riser-rated cable
- CPlenum-rated cable
- DShielded twisted pair with a standard PVC jacket
Show answer & explanationAnswer & explanation
Correct answer: C. Plenum-rated cable
Plenum spaces used for air circulation require plenum-rated cable, which has a jacket that produces less smoke and toxic fumes when burned, as mandated by fire codes. PVC cable releases toxic gas when it burns and is not permitted in plenum spaces.
Why the other options are wrong
- A. Direct burial cable is designed for underground installation, not indoor plenums.
- B. Riser-rated cable is for vertical shafts between floors, not plenum spaces.
- D. Standard PVC jacket cable emits toxic smoke and is prohibited in plenum spaces.
Plenum-Rated Cable
Cabling with a fire-resistant, low-smoke jacket required for installation in plenum spaces (air ducts/return-air spaces) per fire code.
- Plenum spaces circulate breathable air
- PVC cable is prohibited there due to toxic smoke
- Plenum cable costs more but is code-required
Memory trick: Plenum air, plenum cable — no toxic smoke allowed.