The secondary power supply capacity must account for which loads during transfer?

The secondary power supply capacity must account for which loads during transfer?

• A. All loads not automatically disconnected during transfer
• B. All loads that are automatically disconnected during transfer
• C. Only life-safety loads
• D. Only non-essential loads

Answer: (A)

When the system switches to the backup power source, you size that backup to cover exactly the loads that stay energized after the transfer. Some nonessential loads may be automatically disconnected to conserve power, but any loads that remain connected during the transfer must be supported by the secondary power supply. That’s why the capacity must account for all loads that are not automatically disconnected during transfer. This typically includes life-safety and other critical circuits, but the key point is the residual, still-on load, not just a subset of loads.

When the system switches to the backup power source, you size that backup to cover exactly the loads that stay energized after the transfer. Some nonessential loads may be automatically disconnected to conserve power, but any loads that remain connected during the transfer must be supported by the secondary power supply. That’s why the capacity must account for all loads that are not automatically disconnected during transfer. This typically includes life-safety and other critical circuits, but the key point is the residual, still-on load, not just a subset of loads.