The Siemens 5SU9604-1KK32 is a 1P+N RCD-operated circuit breaker (RCBO) from the SENTRON family, combining overcurrent protection and residual current detection in a single 18 mm wide module. Rated 32 A with a 10 kA breaking capacity per EN 60898 and IEC 60947-2, it trips on both overload/short-circuit (C-curve) and earth leakage at 300 mA, Type AC. That 300 mA trip threshold means it catches sinusoidal AC fault currents to ground — standard for general-purpose socket circuits and lighting final subcircuits where DC-sensitive electronics aren't present.
One modular width unit (18 mm) on standard DIN rail. Depth 77 mm, height 125 mm, installation depth 70 mm. Mounting position any — no derating for horizontal or inverted orientation. IP20 with conductors connected, so it lives inside a distribution board or enclosure, not exposed. Touch protection built in. Supply feed from top or bottom; no forced polarity on the line side.
Derating and thermal reality
At 40 °C it's 30.08 A; at 45 °C, 29.12 A; at 50 °C, 27.84 A; at 55 °C, 25.92 A. If your panel ambient runs 50 °C, size the upstream breaker for 28 A continuous, not 32. The 75 °C maximum and -40 °C minimum cover storage and operation — the -40 °C floor matters for unheated seasonal enclosures.
Current production — no phase-out or NRND flag on this order code. No official successor listed; this is the active variant.