RCCB for 400 V three-phase panels — 63 A, 100 mA trip, type AC
The 5SM3446-0LB: The 10 kA short-circuit current rating (IEC 60947-2) tells you this RCCB can safely interrupt a fault up to 10 kA at the rated voltage without welding contacts or cascading failure upstream. In a panel fed by a transformer with a 10 kA prospective fault level or less, this unit holds its own without needing a backup fuse or upstream MCB to limit the let-through.
DIN-rail fit and conductor termination
Mounts on a standard DIN rail (REG profile) and occupies 4 width units — 72 mm of rail space. The 70 mm installation depth is standard for the SENTRON 5SM3 family, so it aligns with the backplane in a typical distribution board. Any mounting position is allowed, and the supply can enter from top or bottom, which saves fiddling with busbar orientation during panel build. Terminals accept solid or stranded conductors from 1.5 mm² up to 25 mm² — covers everything from a 2.5 mm² lighting circuit tail up to a 16 mm² or 25 mm² main feeder. Tightening torque is 2.5 to 3 N·m, typical for the screw-type terminals on this class of RCCB. The IP20 rating applies once the distribution board is installed with conductors connected; the device itself is finger and back-of-hand safe per the protection against electrical shock listing.
Environmental and mechanical limits
Ambient temperature range for operation is -5 to +45 °C; storage range is -40 to +75 °C. The 10 000 mechanical switching cycles typical is standard for a panel-mounted RCCB — adequate for a distribution board that sees infrequent manual test operations plus occasional fault trips. Silicon-free construction is noted, which matters for potting or conformal-coating processes in certain industrial electronics enclosures.