At 415 V and 440 V it still holds 121 kA, dropping to 79 kA at 500 V and 5.1 kA at 690 V. The ETU320 is a basic adjustable thermal-magnetic replacement — you get fixed pickup and time-delay curves, no communications or ground-fault module. An undervoltage release (UVR) is integrated as standard (order code for the release sub-assembly is 3VA9608-0BB11). Thermal derating is published for the full range: 250 A continuous up to 50 °C ambient, then 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. Power dissipation maxes at 50.5 W — that's modest for a 250 A frame, so ventilation in a standard IP54 enclosure is usually adequate. No auxiliary contact or shunt trip is fitted as standard; the UVR is the only integrated release.
That's a standard 4-pole MCCB form factor for a 250 A frame — it will bolt directly onto a mounting plate or DIN-rail adapter (the SENTRON 3VA range uses a common screw-fix pattern). Verify the busbar system is rated for the 250 A continuous current and the prospective fault level at the point of installation.