MCCB for line protection — 400 A continuous, 4800 A frame
Rated 400 A continuously across the full 40 °C to 70 °C ambient range (no derating needed up to 70 °C), it carries a 4800 A frame that gives headroom for selectivity coordination with smaller downstream breakers. Short-circuit breaking capacity is voltage-dependent: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 9 kA at 690 V. The 5 kA limited-to-1-second rating is the short-time withstand for selective coordination — the breaker can hold closed under fault for up to 1 s to let a downstream device clear first. Maximum power loss is 66 W.