To prevent faults from propagating, protection devices in feeders and motor control centers must be coordinated in what way?

• A. Prevent faults from propagating beyond the source
• B. Increase the likelihood of simultaneous trips
• C. Increase energy efficiency
• D. Reduce the need for insulation

Answer: (A)

Protection devices must be coordinated so that a fault is cleared by the device closest to it, isolating the fault at its source and preventing the disturbance from spreading through feeders and the motor control center. This selective tripping keeps the rest of the system powered and limits damage, while downstream devices operate quickly for local faults and upstream devices wait, avoiding unnecessary widespread outages.

The other ideas don’t fit: making trips more likely to happen at the same time would defeat selectivity; protecting efficiency isn’t the goal of coordination; and insulation needs aren’t determined by how protective devices are coordinated.