The Siemens 5SV5344-0 is a SENTRON 4-pole residual current circuit breaker (RCCB), Type AC, rated 40 A with 30 mA sensitivity at 400 V AC. The 30 mA trip threshold covers personnel protection (hand-to-ground fault path) while avoiding nuisance trips from normal cable capacitance on shorter runs.
Rated at 40 A continuous and 400 V AC phase-to-phase, this RCCB handles the full load of a typical 40 A sub-distribution board feeding lighting, socket outlets, and small HVAC equipment. The 30 mA sensitivity is the standard for personnel protection in most IEC-based installations. It will trip within 300 ms at rated residual current, faster at higher fault currents. The device is instantaneous — no intentional time delay — so it coordinates with upstream delayed-type RCCBs in a selective scheme only if the upstream device is marked S (selective) with a higher rating.
Depth is 70 mm, which leaves clearance in standard 100 mm deep enclosures. Silicon-free construction is a detail worth noting for automotive paint-shop or coating-line panels where silicone outgassing can cause adhesion failures.