The Siemens SENTRON 5SU1353-1KL25 is a 2-pole RCBO (residual current circuit breaker with overcurrent protection) rated 25 A at AC, C-curve, with a breaking capacity of 4.5 kA per EN 60898.
Current derating and ambient range
Rated 25 A at 30 °C, the unit derates to 23.5 A at 40 °C, 22.75 A at 45 °C, 21.75 A at 50 °C, 20.25 A at 55 °C and 60 °C, and 19.25 A at 65 °C, down to 18.25 A at 70 °C. For a panel running near 40 °C ambient, plan for a 23.5 A continuous load — the 25 A rating is a 30 °C benchmark, not a hard limit.
Integration notes
The supply cord can enter from either top or bottom. Halogen-free and silicon-free construction suits environments with sensitive electronics or low-smoke requirements. Instantaneous design (no intentional delay) for direct fault clearing.