Which wiring method is a two-hour rated method?

• A. Type FPLP-CI cable
• B. Type NM-B
• C. Type AC cable
• D. Type THHN in conduit

Answer: (A)

Two-hour rated wiring means the cable or assembly is listed to maintain circuit integrity for two hours in a fire-resistance-rated wall or ceiling. FPLP-CI cable is designed for that purpose and is listed as a fire-rated option capable of meeting a two-hour rating when installed in the approved rated assemblies. Other common wiring methods—NM-B, AC cable, or THHN in conduit—are standard installations and are not inherently rated to provide a two-hour fire rating on their own; they would require additional fire-rating measures to achieve the same requirement. When a two-hour rating is needed, selecting a listed two-hour rated cable like FPLP-CI and following the listing’s installation instructions is the appropriate approach.