What this 400 A MCCB does for your main feeder
The interrupting ratings are serious: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V — so it handles high available fault current without cascading upstream. This breaker includes a communication function and comes with one auxiliary switch plus one trip alarm switch. The ETU560 trip unit gives you adjustable protection curves and a local trip indicator so when it does open, you know why.
Thermal derating — what 400 A really means at your ambient
At 55 °C it's still good for 375 A, at 60 °C for 350 A, and so on down to 300 A at 70 °C. If your switchroom runs hot, this gives you a clean derating curve to work with instead of guessing.