What this 250 A MCCB carries
It's built for line protection — think main feeder or large motor branch in a distribution panel where you need a solid 250 A handle and high interrupting capacity. Breaking capacity hits 121 kA at 240 V, drops to 75.6 kA at 415 V, 25 kA at 440 V, and 11.9 kA at 690 V — so it handles serious fault currents on low-voltage industrial systems without upstream fuses.
The breaker carries full 250 A up to 50 °C ambient; above that it derates to 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. That's a shallow derate curve — you don't lose much headroom in a warm enclosure. Front IP40 protects against tool probes; operating range is -25 °C to 70 °C, storage from -40 °C to 80 °C.