Breaking capacity is the headline number here: 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. Current rating holds at 125 A from 40 °C through 50 °C ambient, then derates to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. Size the feeder accordingly.
Duty and fit
The 4-pole construction handles three-phase plus neutral switching. Power loss maxes at 28.1 W — not negligible in a sealed cabinet. If you're packing multiple breakers in a small enclosure, factor that heat into the thermal budget or you'll push the derating curve harder than the table shows.