Siemens SENTRON 5SU9104-1KK25 — RCD-operated circuit breaker, 25 A, C-curve, 10 kA
The Siemens 5SU9104-1KK25 is a 1P+N RCD-operated circuit breaker from the SENTRON 5SU9 series, combining overcurrent and residual current protection in a single 18 mm wide unit. Rated 25 A at 30 °C with a C tripping characteristic, it clears faults up to 10 kA per EN 60898 and IEC 60947-2. The instantaneous design means no intentional time delay on the RCD element — it trips on residual AC fault currents immediately. Rated current derates with ambient temperature: 23.5 A at 40 °C, 22.75 A at 45 °C, 21.75 A at 50 °C, and 20.25 A at 55 °C. For a panel running at 40 °C ambient, the effective continuous load limit is 23.5 A — not the 25 A nameplate. Plan your branch circuit load accordingly. The 18 mm width (one width unit) fits standard DIN-rail enclosures. Depth is 77 mm, installation depth 70 mm. Halogen-free and silicon-free construction, with touch protection on the terminals. Energy limiting class 3. Overvoltage category III. Ambient operating range -25 to +45 °C; storage range -40 to +75 °C.