400 A MCCB with ground-fault and comms — what you need to know
It carries a trip unit adjustable from 600 A to 4 000 A, so you can fine-tune the overload threshold to match your transformer or feeder without swapping hardware.
The interrupting rating drops as voltage rises — expected for any MCCB. At 240 V it clears 440 kA; at 415 V and 440 V it holds 330 kA; at 500 V it still manages 220 kA; at 690 V it's 52.5 kA. For a 400 A frame these are strong numbers, especially the 330 kA at 415 V — typical for large transformer secondaries or industrial service entrances where fault current can exceed 200 kA.
Above that it derates: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. The storage limit matters if you're holding spares in a non-conditioned warehouse — keep them above -40 °C and below 80 °C and they'll be fine on the shelf for years.