The Siemens 5SV9316-0PK40 is a SENTRON RCD-operated circuit breaker — an RCBO combining overcurrent and residual current protection in a single 18 mm-wide module. Rated 40 A at 50 Hz with a Type B tripping characteristic, it clears faults up to 6 kA per EN 60898 and IEC 60947-2. The 1P+N configuration protects one live conductor while switching the neutral, common in single-phase final subcircuits where you want both poles isolated on a fault.
The 40 A rating is the continuous current at 30 °C ambient; it derates to 38 A at 40 °C and 36 A at 50 °C, so if your panel runs hot, factor that in. Type B trips at 3–5× rated current, meaning it handles modest inrush from resistive and small motor loads but will nuisance-trip on high-starting-current equipment — that's the right call for general-purpose socket circuits and lighting, not for large drives or transformers. It detects AC-type residual currents only — sinusoidal AC earth faults. That covers most general wiring, but if your loads include variable-speed drives, UPS systems, or switched-mode power supplies that generate pulsed or DC fault currents, you need a Type A or Type B RCD instead.
Snaps onto a standard 35 mm DIN rail, occupies one width unit (18 mm), and accepts solid or stranded conductors from 0.75 mm² up to 16 mm² — enough for the 40 A feed. The supply connects from below per the datasheet. Depth is 77 mm, installation depth 70 mm, so it clears most shallow enclosures. IP20 with the distribution board installed and conductors connected — it's not a standalone outdoor device. Mounting position is any, which helps in tight panels. Power dissipation maxes at 9.68 W — not negligible if you pack a dozen of these in a sealed enclosure; account for the heat.