The Siemens SENTRON 5SU1644-6KK82 is a 4-pole RCBO (residual current breaker with overcurrent protection) rated 125 A at 30 °C and 10 kA breaking capacity per EN 60898 and IEC 60947-2.
At 40 °C it derates to 115.62 A, at 50 °C to 106.25 A, and at 60 °C to 96.25 A — so a panel running warm loses roughly 23% of the headline capacity. For a 100 A continuous load in a 50 °C enclosure, the 5SU1644-6KK82 still has headroom; at 60 °C it's marginal.
Snap-on DIN-rail mount, 11 modular width units wide (198 mm). Depth is 77 mm, height 90 mm. The IP20 rating applies once the distribution board is installed with conductors connected — not for open-panel wiring. Mount in any position.