The Siemens 5SU1356-0DA16 is a combined residual-current device and miniature circuit breaker (RCBO), known in the trade as an FI/LS-protector. It pairs Type AC earth-leakage detection at 30 mA with a B-curve overcurrent trip at 16 A, all in a single 1+N-pole module rated for 6 kA breaking capacity. The pig-tail neutral connection simplifies wiring in distribution boards where the neutral bar is already landed.
The 30 mA residual-current threshold is the standard for personal shock protection in residential and commercial final circuits — it catches leakage through a person touching a live conductor. The B-curve 16 A overcurrent trip handles general-purpose socket outlets and lighting circuits where inrush is moderate. The 1+N-pole format switches the line and disconnects the neutral in a single module, saving a DIN-rail width compared to separate RCD and MCB.