In protective coordination, which statement describes the desired outcome?

• A. It ensures all devices open at fault.
• B. It ensures the device with the highest rating opens first.
• C. It ensures only the device nearest the fault opens.
• D. It uses automatic reclosing.

Answer: (C)

Selectivity in protection means the device closest to the fault should operate to clear it, so only that section is opened and the rest of the system remains energized. This minimizes the area that loses power and keeps service intact for as many customers as possible. Upstream devices should stay closed unless the local device fails to trip or the fault extends beyond its protection zone. The other statements don’t describe this outcome: tripping all devices would cause unnecessary outages, tripping the highest-rated device first would disrupt the intended sequential clearing, and automatic reclosing is a separate control action, not the fundamental aim of coordination.