Electrical Safety Level 2 Practice Test

Incident energy during an arc fault depends on two main factors: the available short‑circuit current and how long the arc lasts before the fault is cleared. A bus arrangement that uses a high‑energy circuit breaker is designed to handle very large fault currents, and depending on the configuration, the arc may persist longer before clearance. That combination means more energy is released in the arc, so the incident energy on the bus is higher.

Other options involve devices or configurations intended for lower energy or faster interruption, so they generally produce less energy during a fault. Therefore, the bus configuration associated with the highest incident energy is the high‑energy circuit-breaker arrangement.