Excluding outdoor locations, which NFPA 99 requirement for the wiring of each of the two mandatory master alarms?

• A. Wired independently to the initiating device(s) for each signal
• B. Common conductors
• C. Without any splices
• D. Alarms shall be sent to the area alarm panel in the emergency room

Answer: (A)

Two master alarms must be wired with independent conductors from each initiating device for every alarm signal. This setup ensures the alarms remain reliable and fault-tolerant: if one circuit or path to an initiating device fails, the other independent path can still carry the signal and trigger the master alarm. Keeping the wiring separate for each signal prevents a single fault from disabling both alarms, which is essential for timely and clear alerts in a medical gas system. Inside facilities (excluding outdoor locations), shared conductors or splices would introduce common points of failure, and routing alarms to a central area panel isn’t the focus of how the master alarms must be wired.