What signal will sound if there is a fault in the fire alarm system?

• A. Alarm signal will sound
• B. Trouble signal will sound
• C. Supervisory signal will sound
• D. None

Answer: (B)

In a fire alarm system, signals are used to convey different situations, not just “fire.” When there’s a fault in the system, the trouble signal sounds. This tells responders that something is not functioning correctly—like a power loss, a wiring fault, a damaged device, or a problem with the supervision circuit—that could prevent the system from operating properly. It’s different from an alarm signal, which indicates a real fire condition, and from a supervisory signal, which indicates a monitored condition that must be kept in a specific state (such as a valve or a protected device). So, a fault triggers the trouble signal to alert maintenance and ensure the issue is addressed.