What is a purpose of the automatic bus transfer device shown in the illustration? Illustration EL-0014

Correct Answer: Option A — Provide power to the 450 VAC emergency bus from the emergency generator in the emergency mode.

Automatic bus transfer devices ensure continuous power availability for vital loads. In the emergency mode, the ABT automatically switches to provide power from the emergency generator to the 450 VAC emergency bus upon loss of normal main switchboard power.