Are copper conductors exclusively required for fire alarm systems?

• A. Yes
• B. No, aluminum is allowed
• C. No, copper and aluminum are allowed
• D. No, copper and steel are allowed

Answer: (D)

Copper conductors are common in fire alarm wiring, but they aren’t the only option. What matters is that the wiring method and the conductors used are listed for fire alarm use and installed per the applicable codes, such as NFPA 72 and NEC 760. In many installed cables, copper carries the signaling current, while steel appears as armor or in the construction of steel‑sheath or armored cables. The steel isn’t necessarily carrying the signal, but it is part of a listed, approved wiring assembly that can be used in a fire alarm system. Because the listing and proper installation govern acceptance, copper conductors are not exclusively required; copper and steel can both be present in a compliant installation.