The 250 A rating holds across 40 °C to 50 °C (–), then derates linearly to 213 A at 70 °C — so if your panel ambient runs hot, you'll need to account for that. Breaking capacity drops from 242 kA at 240 V to 187 kA at 415 V and 6 kA at 690 V; the 690 V figure is low, so this breaker is best suited for 240–480 V systems where the high interrupt rating matters.
The 3-pole frame mounts via screw terminals or plug-in base; no DIN-rail mounting on this class. Plan for 48 W maximum power loss in the enclosure thermal budget.