What this MCCB brings to a panel
Breaking capacity hits 242 kA at 240 V, 187 kA at 415 V, and still 40 kA at 690 V — that's enough to handle high-fault utility feeds or transformer secondaries without cascading upstream. The auxiliary contact set includes two auxiliary switches plus a separate trip alarm switch (HQ), letting the PLC know exactly when the breaker tripped on a fault versus a manual open.
Thermal derating — what the 400 A rating really means
The 400 A rating holds flat from 40 °C up to 50 °C, then derates gradually: 384 A at 55 °C, 376 A at 60 °C, 368 A at 65 °C, and 360 A at 70 °C. That storage floor matters if the spare sits in an unheated warehouse over winter.