Siemens SENTRON 5SM3346-0LA — 4-pole RCCB, 63 A, 30 mA, Type AC
The Siemens SENTRON 5SM3346-0LA is a 4-pole residual current operated circuit breaker (RCCB) rated at 63 A with a 30 mA tripping residual current, designed for 400 V AC systems at 50 Hz. The 30 mA sensitivity provides personal protection against direct contact, while the 63 A rating handles the full load current of a large submain or a group of downstream circuits.
Rated at 63 A and 400 V AC, this RCCB is sized for a three-phase four-wire sub-distribution board. With thermal overload protection built in, the 5SM3346-0LA combines residual current detection with overcurrent sensing in a single unit — it will trip on sustained overload as well as on earth fault, reducing the number of devices needed in the panel. The 30 mA residual current setting is the standard threshold for personal protection against electric shock (IEC 60364-4-41), making this unit appropriate for final circuits supplying socket outlets or portable equipment where direct contact risk exists.
Mounts on DIN rail (REG) and occupies 4 width units of panel space. Screw-type terminals accept solid or stranded conductors from 1.5 mm² up to 25 mm², with a recommended tightening torque of 2.5 to 3 N·m — enough for the 63 A rated current without oversizing the terminal. Installation depth is 70 mm, matching the standard depth of modular DIN-rail devices, so it sits flush with adjacent breakers and contactors.
Silicon-free construction matters for applications where silicone outgassing can contaminate sensitive surfaces, such as in paint shops or electronics assembly areas.
It is part of the Siemens SENTRON 5SM3 series of RCCBs, which are widely specified in European-standard distribution boards and are available through standard industrial distribution channels.