What this FI/LS protector does on the panel
The Siemens 5SU1353-0KV06 is a combined residual-current device and miniature circuit breaker (RCD/MCB combo) — one unit, one DIN-rail footprint, one pair of terminals in and out. It saves a module width over separate devices and eliminates the wiring between them. The Type AC detection handles sinusoidal AC earth faults; the 30 mA trip threshold covers personnel protection (additional protection per IEC 60364). The B-curve 6 A thermal-magnetic side clears overcurrents on resistive or light inductive loads — lighting circuits, small control transformers, socket outlets in commercial or residential sub-distribution.
What the ratings mean for fit
4.5 kA breaking capacity at the rated voltage — adequate for domestic and light commercial sub-distribution where the prospective short-circuit current stays under that level. The 1+N-pole format switches the line conductor and opens the neutral; the neutral pole is not a switched pole in the overcurrent sense but provides isolation. The 70 mm depth (D=70MM) is the installed depth from the DIN-rail front face — check enclosure depth clearance if retrofitting into a shallow box.