The Siemens SENTRON 5SU1353-1WM32 is a 1P+N RCBO combining overcurrent and residual current protection in a single 2-module-wide unit. Rated at 32 A with a C tripping curve and 30 mA AC-type residual sensitivity, it handles the common residential and light-commercial branch circuit where both short-circuit and earth-fault protection are needed in one DIN-rail slot. The C-curve (5–10× In) suits inductive loads like small motors, pumps, and fluorescent lighting banks that produce moderate inrush without nuisance tripping. Breaking capacity is rated at 4.5 kA per EN 60898 for domestic distribution boards and 15 kA per IEC 60947-2 for industrial panel applications — a useful headroom gap that lets this RCBO serve both a final-sub circuit and a sub-distribution board with higher prospective fault current. The 30 mA residual threshold provides supplementary protection against direct contact in standard dry environments. Mounts in any position on a DIN rail, accepts solid or stranded conductors from 0.75 to 35 mm², and the screw terminals call for 2.5 to 3 N·m torque. The 70 mm installation depth fits standard SENTRON distribution boards and most generic enclosures. Supply feed can enter from top or bottom — no orientation restriction during panel build.
Integration notes
Two width units (36 mm at 18 mm/module) on the DIN rail. The 1P+N configuration switches the phase and disconnects the neutral — the neutral conductor is switched internally, so no separate neutral bar connection is needed downstream of the RCBO for the protected circuit. Overvoltage category III rated, suitable for fixed-installation distribution boards downstream of the utility meter. IP20 protection applies once the distribution board is installed with conductors connected — the front face is touch-protected (finger-safe terminals). Ambient temperature range -25 to +55 °C, storage -40 to +75 °C. Maximum power dissipation 11.4 W at rated load; factor into enclosure thermal calculations if multiple RCBOs are ganged in a sealed board. Halogen-free and silicon-free construction — relevant for clean-room or high-reliability installations where outgassing or silicone contamination is a concern. Surge current withstand 1 kA (8/20 μs waveform), energy limiting class 3. Mechanical endurance 10 000 switching cycles typical.
Coordination and selectivity
The C-curve characteristic (tripping between 5× and 10× In) coordinates with upstream SENTRON S-series or 3VA moulded-case breakers in a selective scheme — the RCBO clears downstream faults before the upstream device sees the full let-through, provided the upstream breaker is sized at least 1.6× the RCBO rating and the fault current stays within the RCBO's breaking capacity. For full selectivity tables, refer to Siemens' SENTRON coordination documentation. The 30 mA residual element is AC-type — detects sinusoidal AC earth faults only. For pulsating DC or smooth DC fault currents (common with VFDs, LED drivers, or EV chargers on the circuit), an A-type or F-type RCBO would be required. This is a standard AC-type unit suited to resistive and inductive loads without rectified electronics downstream.