RCD-operated circuit breaker, 1P+N, C20, 10 kA
The Siemens SENTRON 5SU9604-1KK20 is a 1P+N RCD-operated circuit breaker — an RCBO — combining overcurrent and residual-current protection in a single 1-MWU (18 mm wide) package. Rated 20 A at 30 °C with a C-curve tripping characteristic, it breaks fault currents up to 10 kA per EN 60898 and IEC 60947-2. That 10 kA SCCR means it can interrupt a bolted fault at the panel without upstream coordination worries in most residential and light commercial distribution boards. Supply can land top or bottom; the unit mounts in any position on a DIN rail. The 77 mm depth (70 mm installation depth) fits standard 125 mm tall enclosures. Halogen-free and silicon-free construction matters for clean-room or high-reliability spec — no corrosive off-gassing if the device faults.
Derating and ambient range
The 20 A rating holds at 30 °C ambient. At 40 °C it derates to 18.8 A, at 45 °C to 18.2 A, at 50 °C to 17.4 A, and at 55 °C to 16.2 A. If the panel runs hot — say a crowded enclosure near a boiler line — size the load side for the derated figure, not the 30 °C number. The operating range spans -40 °C to 75 °C, with 95% humidity tolerance, so it handles outdoor enclosures in cold climates or humid process areas.