Thermal derating — the real-world number
At 60 °C it derates to 955 A, at 65 °C to 885 A, and at 70 °C to 815 A.
Trip unit and adjustable settings
The ETU350 release gives you adjustable long-time pickup Ir from 0.5 to 1.0 x Iu (500 to 1000 A), short-time delay tsd from 0.04 to 0.4 s, and instantaneous pickup Ii adjustable up to 10 000 A. That range lets you coordinate downstream feeders while keeping the main breaker selective — useful on a distribution board where you don't want a branch fault taking the whole panel dark.
The 3VA2510-5HN32-0DL0 measures 120 mm deep by 210 mm wide by 320 mm tall — that's about 8.3 x 12.6 inches in the old measure. Front protection is IP40, meaning it's sealed against tools and wires but not against washdown; keep it inside the enclosure, not on the door.