What it is and what it does
The Siemens 5SV5312-0MB is a 2-pole residual current operated circuit breaker (RCCB) from the SENTRON family, Type AC, rated 25 A with 30 mA trip sensitivity for 230 V AC circuits. It is an instantaneous-trip device — no intentional short-time delay — so it clears ground-faults as fast as the waveform allows, which is the standard choice for general-purpose socket and lighting circuits in residential and commercial distribution boards. The 30 mA sensitivity is the common threshold for personal protection against direct contact. The 6 kA short-circuit current rating (SCCR) means the device can safely interrupt a fault up to that level.
Panel integration and mounting
Snaps onto DIN rail (REG) and occupies 2 modular width units (36 mm). The 70 mm installation depth leaves clearance behind a standard enclosure gland plate. Mounting position is unrestricted. Supply can enter from top or bottom; the design is symmetrical for wiring convenience. IP20 rating applies only when the distribution board is installed with all conductors connected — the front face is touch-safe, but the terminals are not sealed against dust ingress until the board cover is on.