What this part is and what it does
The Siemens SENTRON 5SM2435-6 is a 3-pole residual current (RC) unit designed to pair with a 5SY miniature circuit breaker, forming a combined residual current circuit breaker with overcurrent protection (RCBO) in a single DIN-rail footprint. It is rated at 63 A with a 100 mA tripping fault current, type A, for 400 V AC systems at 50 Hz.
Key ratings and what they mean for your panel
The 63 A rating is the nominal current at 40 °C; above that, the unit derates linearly to 50.4 A at 70 °C (–). In a warm enclosure, size the upstream protection for the derated value, not the 63 A nameplate. Type A residual current detection covers sinusoidal AC and pulsating DC fault currents — the standard for single-phase rectified loads like switched-mode power supplies and variable-speed drives. The 100 mA trip threshold suits sub-distribution or feeder protection where 30 mA would nuisance-trip on leakage. Mounts on DIN rail (REG) in any position. The 3-module width and 70 mm depth fit standard distribution boards. IP20 with connected conductors means it's for enclosed panels only — not for wet or dusty environments.