The breaking capacity is 121 kA at 240 V AC and 75.6 kA at 415 V AC, which gives solid fault-clearing headroom for most industrial secondary distribution boards.
Thermal derating — what the 40–70 °C table tells you
At 55 °C it derates to 31 A, at 65 °C to 30 A, and at 70 °C still carries 30 A. That's a shallow curve — only 2 A lost over a 30 °C rise — so it's well suited for a warm panel near a kiln or furnace line where ambient climbs but you can't oversize the breaker.
The breaker measures 70 mm deep, 50.8 mm wide, and 130 mm high. That 50.8 mm (2-inch) width per pole is standard for SENTRON 3VA MCCBs — it occupies roughly two 18 mm module spaces on a DIN rail. Maximum power loss is 7.06 W, so no special ventilation is needed in a typical steel enclosure.