What this 1-pole MCCB is for
At 415 V AC the interrupt rating drops to 7.5 kA, so you'll want to check available fault current before landing it on a 400 V bus.
The 25 A rating holds steady from 40 °C through 50 °C, then steps down to 24 A at 55–60 °C and 23 A at 65–70 °C. That's a gentle slope — you don't lose much headroom in a warm enclosure. The 2.83 W maximum power loss is low enough that you can pack several of these on a DIN rail without cooking the adjacent breakers.
Panel fit and physicals
The 3VA1125-3ED16-0AA0 measures 70 mm deep, 25.4 mm wide (1 inch), and 130 mm tall.