What it is and what it does
The Siemens 5SU1336-7FP16 is a SENTRON RCBO — a combined residual-current circuit breaker and miniature circuit breaker in one 3-pole unit, designed for 400 V AC, 50 Hz systems. The Type C tripping characteristic handles inrush currents from motor and lighting loads without nuisance trips, while the residual-current element provides earth-leakage protection. Rated 16 A at 30 °C ambient, with a 6 kA breaking capacity per both EN 60898 and IEC 60947-2, it covers the standard domestic and light commercial fault-clearing requirement.
Temperature derating — the real-world rating
The headline 16 A rating holds only at 30 °C. Inside a crowded panel where ambient climbs to 40 °C, the continuous current drops to 15.2 A; at 50 °C it's 14.3 A; at 60 °C it's 13.4 A; and at the maximum 70 °C it's 12.5 A. If your load is close to 16 A and the panel runs warm, you need to account for this derating or move up a frame size.
Mounting and integration
Occupies 3 modular width units (54 mm) on a DIN rail, with a depth of 72 mm and height of 85 mm. Mounting position is any orientation; supply can enter from top or bottom. The IP20 rating applies only when installed in a distribution board with conductors connected — this is a panel-internal device, not for exposed or wet locations.