What it is and what it does
The Siemens SENTRON 5SU1656-7KK32 is a combined residual current circuit breaker with overcurrent protection (RCBO) in a 2-module-width (36 mm) housing. It protects a single-phase final subcircuit against both overload/short-circuit (via the C-characteristic magnetic/thermal trip) and earth leakage (via the 300 mA Type A residual current sensor). The 6 kA breaking capacity per EN 60898 is adequate for most domestic and light commercial distribution boards where the prospective fault current at the point of installation stays under that threshold.
Ratings and their meaning for the buyer
Rated at 32 A at 30 °C ambient, the RCBO derates linearly as panel temperature rises: 30.4 A at 40 °C, 28.8 A at 50 °C, 27.2 A at 60 °C, and 24.64 A at 70 °C. If the distribution board runs warm — say 50 °C inside the enclosure — the continuous load must not exceed 28.8 A, not the 32 A nameplate. The 300 mA residual trip threshold is a standard value for general-purpose socket-outlet circuits where a lower 30 mA threshold would cause nuisance tripping from cable capacitance or inrush. Type A detection covers sinusoidal AC and pulsating DC residual currents, which is the minimum requirement for circuits with single-phase rectified loads (e.g., washing machines, LED drivers).
Panel integration and mounting
Snaps onto 35 mm DIN rail per EN 60715. The 36 mm width (2 modular units) fits standard distribution board cutouts. Supply can enter from either top or bottom, and the RCBO can be mounted in any orientation. The IP20 rating applies only when installed in a distribution board with connected conductors — the device itself is not sealed for exposed installation. Halogen-free and silicon-free materials suit environments where outgassing must be minimized (e.g., clean rooms, medical facilities).