Siemens SENTRON 5SM3346-0LA01 — 2-pole RCCB, 63 A, 30 mA, Type AC
The Siemens SENTRON 5SM3346-0LA01 is a 2-pole residual current operated circuit breaker (RCCB) from the 5SM3 series, designed for 230 V AC single-phase networks at 50 Hz. The short-time delayed characteristic (selective type K per IEC/EN 61008) provides coordination with downstream devices, preventing nuisance tripping from transient leakage currents typical of connected electronics or long cable runs.
The 63 A rated current matches the main incoming supply for a typical residential or small commercial single-phase board; it is not a branch-circuit device. The short-time delayed design introduces a deliberate trip delay (typically 10–40 ms per IEC 61008-2-2) so that a downstream MCB or RCCB clears a solid fault first, maintaining supply to healthy circuits — essential for selectivity in multi-tier distribution. The 2-pole construction switches both phase and neutral, which is mandatory for single-phase RCCB applications in many national wiring rules (e.g., VDE 0100, BS 7671). The neutral pole is not switched on the 5SY MCB peers — this RCCB does. Tightening torque is 2.5 to 3 N·m, typical for a 25 mm² terminal — use a torque screwdriver to avoid terminal heating.
Mounts on DIN rail (REG) per EN 60715, occupying 4 width units (72 mm at 18 mm/module). Installation depth is 70 mm, fitting standard 100 mm deep enclosures. The mounting position is unrestricted — horizontal, vertical, or inverted all work, though top-feed is conventional. Supply connection can be top or bottom, which simplifies busbar or cable routing in a crowded board.
The device is silicon-free, relevant for potting or conformal-coating processes in certain industrial or automotive panel builds. The product includes thermal overload protection, which is unusual for an RCCB and provides additional protection against sustained overcurrents that could damage the device.