What this 250 A MCCB does on the line
Breaking capacity is 121 kA at 240 V, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V, so it can interrupt high fault currents on the secondary side of a step-down transformer or at a main distribution board. An undervoltage release (UVR) is built in — if the supply voltage drops below the release threshold, the breaker trips. That's useful for motor circuits where you want the breaker to drop out on a brownout rather than let the motor stall and draw locked-rotor current. The UVR is factory-fitted; no separate module to wire in.
At 40 °C the breaker carries its full 250 A. It holds 250 A up to 50 °C, then derates to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. The 59.5 W maximum power loss also adds heat inside the enclosure; factor it into the thermal budget. Dimensions are 140 mm wide, 158 mm high, 70 mm deep. The 4-pole width is wider than a 3-pole unit; check the enclosure gland plate and busbar spacing before committing.