The interrupting ratings climb to 187 kA at 240 V AC and 121 kA at 415 V AC, so it handles high available fault current on a 400 V distribution board without needing a current-limiting fuse upstream.
At 55 °C it drops to 39 A, at 65 °C to 38 A, at 70 °C to 37 A. That's a gentle slope; most panel builders can leave it at 40 A unless the cabinet runs hot. The interrupting rating at 415 V (121 kA) is the one that matters for a 400 V distribution board — it's well above typical 25–65 kA SCCR requirements, so you get selectivity headroom without stacking fuses. Power loss is 10.8 W max, which is modest for a 40 A MCCB — helps keep the enclosure heat budget under control.
Physical fit and auxiliary wiring
The breaker measures 130 mm high, 76.2 mm wide, 70 mm deep — standard 3-pole MCCB footprint for a 40 A frame. It ships with two factory-installed HQ auxiliary switches (form C, rated for control-circuit duty), so you don't need to order and snap them on separately. That's another SKU I don't need to track. The base switch is the 3VA11405EF320AA0 variant — this order code adds the aux switches at the factory.