The Siemens 5SM3346-4 is a 4-pole residual current circuit breaker (RCCB) from the SENTRON family, type B, short-time delayed, rated 63 A with 30 mA sensitivity on a 400 V AC supply. The 10 kA short-circuit current rating (SCCR) means it safely interrupts faults up to that level without cascading upstream — critical for coordination in a distribution board. Type B detection covers AC, pulsating DC, and smooth DC fault currents, which is what you need when variable-speed drives or UPS equipment sit downstream.
Panel fit and mounting
Snaps onto DIN rail (REG), occupies 4 modular width units (72 mm wide), and can be mounted in any position. Depth is 77 mm with a 70 mm installation depth — verify the enclosure depth if retrofitting into a shallow gland plate. IP20 with connected conductors, so it belongs inside a distribution board, not in a wet location.