What this 400 A MCCB delivers — and what to watch
Interrupting capacity is the real selector here: 242 kA at 240 V, 187 kA at 415/440 V, 121 kA at 500 V, and 7.5 kA at 690 V. That 242 kA figure at 240 V means it can sit on a high-fault transformer secondary without cascading upstream — useful for a main breaker in a 240 V delta or 277/480 V wye panel where the available fault current is north of 100 kA. This is a line-protection design (not motor-protection), so the trip curve is set for cable and bus protection.
Dimensions: 248 mm height, 138 mm width, 110 mm depth — that's a 9.76 x 5.43 x 4.33 inch footprint. Power loss is 96 W maximum at rated current. That's not trivial — in a sealed, non-ventilated enclosure, that heat has to be factored into the thermal budget. If you are packing multiple breakers side by side, derate per the manufacturer's grouping factors or add forced ventilation.