The Siemens 5SU9306-0KK10 is a 1P+N RCD-operated circuit breaker from the SENTRON 5SU9 series — a combined overcurrent and residual current device (RCBO) that fits a single 18 mm width unit on the DIN rail. It's rated 10 A with a B tripping characteristic, meaning it trips between 3 and 5 times rated current for fast magnetic release on short circuits, and it handles fault currents up to 6 kA per EN 60898 and IEC 60947-2.
Above that, the continuous current must be derated: 9.4 A at 40 °C, 9.1 A at 45 °C, 8.7 A at 50 °C, and 8.1 A at 55 °C. If the distribution board runs warm — common in a crowded enclosure — factor the actual load against the derated figure, not the 30 °C headline number.
Wiring and installation
Terminals accept solid or stranded conductors from 0.75 mm² up to 35 mm² — covers everything from 1.5 mm² lighting circuits up to 10 mm² submain tails. Touch protection is built in.