What it is and where it fits
The Siemens SENTRON 5SV3354-6 is a 4-pole residual current circuit breaker (RCCB) — Type A, rated 40 A, tripping at 30 mA residual current. It snaps onto a DIN rail (REG) and occupies 4 modular width units (72 mm wide) in a standard 60 mm grid distribution board. The 70 mm depth keeps it flush with adjacent breakers in a typical panel layout.
What the ratings mean for your panel
40 A rated current holds across the full ambient range from -25 °C to 70 °C — no derating needed up to that ceiling. The 30 mA trip threshold covers personnel protection (hand-to-hand or hand-to-ground fault paths) per IEC 61008-1. Type A detection handles pulsating DC residual currents from single-phase rectifiers (common in washing machines, LED drivers, EV chargers) plus sinusoidal AC — so it's the standard choice for mixed-load residential and light commercial panels. The 10 kA short-circuit current rating (SCCR) means the device safely interrupts faults up to that level without welding contacts or cascading upstream; the let-through current is limited to 5 200 A, and the I²t withstand is 58 000 A²·s — both figures matter for coordination with the upstream MCB or fuse.