What this RCCB does and where it fits
The Siemens SENTRON 5SM3312-6BA is a 2-pole residual current circuit breaker (RCCB) rated 25 A at 230 V AC, with a 30 mA trip sensitivity and type A residual current detection — meaning it catches sinusoidal AC faults plus pulsating DC faults from rectified loads like VFDs, switching power supplies, or LED drivers. The instantaneous design (no short-time delay) suits it for general-purpose shock protection in residential and light commercial distribution boards. It snaps onto a DIN rail (REG) and occupies 2 modular width units (36 mm), with a 70 mm installation depth that fits standard SENTRON enclosures.
Temperature range and mounting
Rated for ambient operation from -25 °C to 45 °C, with storage extremes from -40 °C to 75 °C. The IP20 rating applies only when the distribution board is installed and conductors are connected — this is a panel-internal device, not for wet or outdoor locations. Mount it in any position on the DIN rail; the supply can enter from top or bottom.