The Siemens 5SM1346-0 is a 4-pole residual current circuit breaker (RCCB) from the SENTRON family, rated 63 A at 400 V AC with a 30 mA trip threshold and Type AC fault-current detection. It is instantaneous — no intentional short-time delay — so it clears earth faults as fast as the waveform lets it, which matters for personnel protection in standard commercial and light-industrial distribution boards. The 30 mA sensitivity is the common shock-protection level for socket-outlet circuits in most IEC-based installations. Mounts on DIN rail (REG), 4 width units wide, and can be installed in any position. The IP20 rating applies once the distribution board is closed and conductors are connected — it is not a standalone outdoor device. Finger and back-of-hand safe against accidental contact (protection against electrical shock). Rated short-circuit current withstand is 10 kA (per IEC 61008-1), though the EN 60898 conditional rating is listed at 0.8 kA — the lower number governs selectivity in a domestic-style board where the upstream MCB limits let-through energy. The I²t withstand is 70 000 A²·s; the let-through current is listed at 7 500 A (likely a typographical unit — that figure is in A, not kA, given the class). Keep the 10 kA SCCR as the coordination target for industrial panels, but verify the upstream device's let-through stays under the RCCB's I²t limit.
Temperature derating — the real current rating in a warm cabinet
This RCCB carries a full 63 A at 40 °C and 45 °C ambient, but above that the current must be derated: 60.48 A at 50 °C, 57.96 A at 55 °C, 55.44 A at 60 °C, 52.92 A at 65 °C, and 50.4 A at 70 °C. If the distribution board sits in a hot machine cabinet or near a solar inverter, use the 50 °C or 55 °C column for sizing — the un-derated 63 A label on the front will mislead you in a 55 °C ambient. The permissible storage range is wider: -40 °C to 60 °C, but the operating range is -5 °C to 45 °C (maximum 45 °C, minimum -5 °C). That -5 °C floor means it is not rated for unheated outdoor sheds in freezing climates without a cabinet heater.
What the approvals mean for panel acceptance
Rated according to IEC 61008-1 and EN 60898, overvoltage category III. The silicon-free marking (Product Feature / Silicon-Free: Yes) matters for automotive or paint-shop panels where silicone outgassing can cause adhesion or coating defects. If the downstream load includes variable-speed drives, UPS systems, or LED drivers that generate pulsed DC fault currents, a Type A or Type B RCCB is needed instead. This Type AC unit is correct for resistive and standard motor loads with no power-electronics front end.
Mechanical and installation details
Installation depth is 55 mm. Test circuit requires minimum 100 V AC.