Its ultimate breaking capacity (Icu) at 240 V is 187 kA, at 415 V and 440 V it holds 121 kA, at 500 V it drops to 75.6 kA, and at 690 V it still interrupts 9 kA.
Thermal derating — the real ampacity in a hot panel
At 45 °C it derates to 600 A, at 50 °C to 570 A, at 55 °C to 540 A, at 60 °C to 510 A, at 65 °C to 480 A, and at 70 °C to 450 A. That 70 °C figure matches the maximum operating temperature of the breaker itself, so if your panel ambient is near that limit you lose nearly 30 % of the rated current. Plan the enclosure ventilation or upsizing accordingly — this breaker's frame can handle the heat, but the trip unit follows the published curve.
The 138 mm width for a 3-pole 630 A frame is standard for this class.