The Siemens 5SU1354-1KK32 is a SENTRON RCBO combining overcurrent and residual current protection in a single 2-module-width (36 mm) package. Rated 32 A at 30 °C with a C tripping curve, it handles the inrush of motor starters and small transformer loads without nuisance trips. The type AC residual current detection covers sinusoidal AC fault currents — the standard choice for general-purpose final circuits in residential and commercial distribution boards. Breaking capacity is 10 kA per EN 60898 and 15 kA per IEC 60947-2, giving selectivity headroom against upstream 25 kA or 36 kA MCCBs in a typical 230/240 V 50 Hz installation. Overvoltage category III and pollution degree 2 suit fixed-installation switchgear in the distribution board.
Thermal derating and mounting
The 32 A rating applies at 30 °C ambient; at 40 °C the continuous current drops to 30.4 A, at 50 °C to 28.8 A, and at 70 °C to 24.64 A. Mounting position is any, and the supply can enter from top or bottom. Installation depth is 70 mm (overall depth 77 mm). IP20 applies once the distribution board is installed with connected conductors.