The interrupting capacity tells the real story: 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 5.1 kA at 690 V. The 121 kA at 415 V covers the common industrial distribution voltage in most of the world; the drop to 5.1 kA at 690 V is still respectable for a 250 A frame at that voltage class. Thermal derating is published across the operating range: full 250 A up to 50 °C, then 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C.
Maximum power loss is 50.5 W — account for that heat in your enclosure thermal calculation, especially if you're stacking multiple breakers in a row.
With 20 000 mechanical/electrical endurance cycles, this is a distribution breaker, not a switching device for frequent motor starts — it's designed to sit closed and clear faults, not cycle daily. The ETU350 release gives you LSI (long-time, short-time, instantaneous) protection curves, which lets you coordinate downstream with smaller MCCBs or fuses. The trip indicator gives a visual flag on the front, so a maintenance walk-through catches a tripped breaker without opening the panel door.