The Siemens SENTRON 5SU9304-1KK10 is a combined RCD and MCB in one 18 mm-wide module — an RCBO (residual-current-operated circuit breaker) that saves a DIN-rail position compared to a separate RCD + MCB pair. It protects a single-phase final subcircuit against both overload/short-circuit (C-curve, 10 A rated) and earth leakage (30 mA, Type AC). The 30 mA sensitivity is the standard for personal protection against indirect contact in residential and commercial installations.
Derating and installation constraints
At 40 °C it derates to 9.4 A, at 45 °C to 9.1 A, at 50 °C to 8.7 A, and at 55 °C to 8.1 A (–). The IP20 rating applies only when the distribution board is installed with conductors connected — so it's not a standalone outdoor device. Depth is 77 mm, installation depth 70 mm; verify gland-plate clearance in shallow enclosures.