What this MCB is and where it fits
The Siemens 5SY8316-8 is a SENTRON miniature circuit breaker with a D tripping characteristic, rated 16 A at AC and built for 3-pole (3P) isolation. The D curve means it tolerates the high inrush currents typical of motor starters, transformers, and discharge lighting — it won't nuisance-trip on a motor start but clears fast on a hard fault. It snaps onto a DIN rail and occupies 3 modular width units (54 mm wide), so it drops into any standard distribution board or control panel.
Breaking capacity and selectivity
Rated 30 kA per IEC 60947-2 at 440 V AC, and 15 kA at DC up to 72 V. That 30 kA figure is the interrupting rating — it can safely clear a fault current up to that level without welding contacts or rupturing the case. For a panel fed by a transformer with a high available fault current, this breaker gives you headroom for selective coordination downstream.
Environmental and mounting notes
Rated for ambient temperatures from -40 °C to +75 °C, with derated current values at elevated temps (15.5 A at 50 °C, 14.99 A at 55 °C). The housing is halogen-free and silicon-free, which matters for clean-room or food-grade zones where outgassing is a concern. IP20 with conductors connected — standard for enclosed distribution boards. Mounts in any position; quick-assembly system for busbar stacking.