Which supply fan shutdown scenario is typically scheduled rather than hardwired safety?

• A. Scheduled On/Off
• B. Emergency Stop
• C. Fault Trip
• D. Overload

Answer: (A)

Scheduling vs hardwired safety controls. Supply fans are often managed by the building automation system with a schedule to match occupancy and ventilation needs, turning on and off at set times to save energy. This is a planned operating control, not a fault condition. The other scenarios—emergency stop, fault trip, and overload—are safety protections that must react immediately to unsafe conditions and are typically wired directly into the protection circuits, independent of schedules. They are designed to shut the system down automatically to prevent damage or injury and usually require deliberate reset. Because of that, the on/off scheduling is the scenario that is typically scheduled rather than a hardwired safety action.