Which statement correctly describes plenum cables relative to riser cables?

• A. Riser Cables Have Stricter Fire Load Requirements Than Plenum.
• B. Plenum Cables Have Stricter Fire Load Requirements Than Riser.
• C. Fire Load Requirements Are Identical For Both.
• D. Plenum Cables Are Not Designed For Fire Retardancy.

Answer: (B)

Plenum spaces are used for heating, ventilation, and air distribution, so cables placed there must limit flame spread and smoke production because air moves quickly through those spaces and could carry fire and toxic fumes. Because of this, plenum-rated cables are required to meet stricter fire performance standards (lower flame spread, lower smoke density) than riser-rated cables. That’s why the statement that plenum cables have stricter fire load requirements than riser cables is correct. Riser cables are allowed somewhat less stringent requirements since they are not in the air-handling paths, though they still must be fire-retardant. The other options don’t fit because riser cables aren’t required to meet stricter limits than plenum cables, the fire load requirements aren’t identical, and plenum cables are indeed designed for fire retardancy.