The Siemens 5SV3344-6LA is a 4-pole residual current circuit breaker (RCCB) from the SENTRON family, rated at 40 A and 400 V AC at 50 Hz.
That is unusual for a thermal-magnetic device; here the RCCB's electronic sensing does not drift with ambient heat the way a bimetallic strip does. The 10 kA SCCR at 400 V AC is the conditional rating per IEC 61008-1, backed by a 0.8 kA rated short-circuit capacity per EN 60898. For practical panel coordination, the 10 kA figure governs: if the upstream breaker can limit let-through energy to that level, this RCCB holds. The Type A waveform detection covers the gap between a plain AC type (sinusoidal only) and a Type B (full DC-sensitive). If your load includes a VFD, a UPS, or LED drivers with front-end rectifiers, Type A is the minimum you should specify. The instantaneous trip design means no intentional time delay — it clears fast on a fault, which is correct for personnel protection but means you cannot coordinate selectively downstream without a time-delay S-type RCCB. Overvoltage category III and finger/back-of-hand touch protection confirm it is rated for fixed-installation distribution boards, not just plug-in portable gear. The silicon-free construction matters for automotive or paint-line panels where silicone outgassing can cause adhesion failures.
Snaps onto DIN rail (REG profile) and occupies 4 width units at 72 mm wide. That is standard for DIN-rail components; the enclosure provides the environmental seal.