The Siemens 5SV5312-0FB is a SENTRON residual current operated circuit breaker (RCCB) — 2-pole, Type AC, rated 25 A with a 30 mA trip sensitivity, for 230 V AC at 50 Hz.
The 70 mm installation depth matches standard SENTRON enclosures — no panel depth surprises. Mounting position is unrestricted, and supply can enter from top or bottom, which simplifies busbar routing in a crowded distribution board.
The 30 mA trip threshold is the standard residual-current sensitivity for personnel protection (IEC 61008-1). Short-circuit withstand is 6 kA per IEC 61008-1, with a 0.5 kA rated conditional short-circuit current — adequate for most final sub-circuits in a TN or TT system where the prospective fault current at the board is under 6 kA. Overvoltage category III, so it's rated for fixed-installation downstream of the service entrance. Ambient range -25 °C to +45 °C operating, storage down to -40 °C. Silicon-free construction — relevant if the board is in a coating or potting environment where silicone outgassing can cause contact issues. Mechanical service life is 2,000 operating cycles typical — this is a protection device, not a daily-switching contactor; it's designed to sit closed and only open on fault or test.