The Siemens 5SU1654-0KV10 is an FI/LS combination unit — an RCBO that integrates a Type AC residual-current device (IΔn 300 mA) and a 10 A B-curve miniature circuit breaker into a single 1+N-pole module. The 10 kA breaking capacity at the rated voltage means it can safely interrupt fault currents up to that level without upstream fuses needing to clear first, which simplifies panel coordination in a domestic or light-commercial distribution board.
What the ratings mean for fit
The B-curve (10 A) trips between 3 and 5 times rated current, so it is sized for resistive and small inductive loads — lighting, socket outlets, control transformers — where inrush is modest. The 300 mA residual sensitivity is a Type AC device, meaning it detects sinusoidal AC earth faults only; it is not suitable for pulsating DC or smooth DC fault currents (those call for Type A or Type F). The 10 kA breaking capacity (per IEC 60898) covers the majority of domestic and light-commercial fault levels; if the prospective short-circuit current at the installation point exceeds 10 kA, a current-limiting upstream MCB or fuse is needed.
Panel integration
The 1+N-pole form factor occupies a single DIN-rail module width (roughly 18 mm per pole, so 36 mm total for the 1+N). The D=70 mm dimension refers to the depth from the DIN rail mounting surface to the front of the enclosure — standard for flush-mounting in a consumer unit or distribution board. Wire-up is conventional: line and neutral through the top terminals, load out the bottom; the neutral is switched and protected internally.