The Siemens 5SU1354-6LB13 is a SENTRON RCBO (residual current circuit breaker with overcurrent protection) in a 1P+N configuration, protecting one live pole and switching the neutral. It is rated 13 A at 30 °C with a Type B tripping characteristic, meaning it trips on short-circuit currents between 3 and 5 times the rated current — standard for general-purpose resistive and small inductive loads in residential and commercial final circuits.
Breaking capacity and selectivity
The 5SU1354-6LB13 carries a 10 kA breaking capacity per EN 60898 and 20 kA per IEC 60947-2. The EN 60898 rating applies to the standard household and light commercial installation; the IEC 60947-2 rating is the industrial-performance figure, giving the device a higher fault-interruption ceiling when installed in an industrial distribution board. The 20 kA figure is the one to use for SCCR coordination studies under IEC 60947-2. The design is short-time delayed G and super resistant K, which means the residual-current trip has a deliberate delay (G characteristic) to coordinate with downstream RCDs and avoid nuisance tripping on transient leakage, while the K characteristic provides immunity to high-frequency leakage from connected electronics.
Thermal derating and installation constraints
The 13 A rating is at 30 °C ambient. At 40 °C the continuous current must be derated to 12.48 A, at 50 °C to 11.96 A, and at 70 °C to 10.01 A. In a crowded DIN-rail enclosure with multiple RCBOs ganged, the internal temperature rise can easily exceed 40 °C; the derating curve per the datasheet is the correct basis for the BOM current assignment, not the 30 °C figure. Mounting position is any, and the supply can enter from either top or bottom. The device occupies 2 modular width units (36 mm) on a DIN rail, with a depth of 77 mm and an installation depth of 70 mm. The IP20 rating applies only when the distribution board is installed with connected conductors — the terminals are not touch-safe when exposed.