The interrupting capacity hits 330 kA at 240 V, 242 kA at 415/440 V, 187 kA at 500 V, and 52.5 kA at 690 V — that SCCR headroom means it can clear a fault without cascading upstream even on high-capacity transformer secondaries or large motor starters. The thermal derating curve is flat from 40 °C to 50 °C (full 400 A), then drops to 384 A at 55 °C, 376 A at 60 °C, 368 A at 65 °C, and 360 A at 70 °C; panel builders should check ambient at the breaker location, not the enclosure inlet. The ETU320 electronic trip unit handles the overcurrent protection curve, and the integrated undervoltage release (UVR) — part 3VA9608-0BB24 — allows a remote safety or E-stop circuit to drop the breaker.
The maximum power loss is 66 W, so factor that into thermal rise calculations for a sealed enclosure. The 15 000 mechanical endurance cycles suit frequent-switching applications like pump or compressor control.