The Siemens 5SU9654-7KK32 is a 1P+N RCBO — a combined residual-current device and miniature circuit breaker in one DIN-rail module. It's rated 32 A with a C-trip curve and a 10 kA breaking capacity, so it protects branch circuits against both overload and earth leakage in a single panel slot. The Type A residual-current element detects pulsating DC faults, not just pure AC sine-wave leakage, which covers modern electronics and variable-speed drives on the line.
Ratings and what they mean on the panel
The 300 mA sensitivity is a common choice for final subcircuits supplying socket outlets in commercial or industrial panels where nuisance tripping from inrush or leakage from multiple loads is a concern — it's less likely to drop out on cable capacitance than a 30 mA unit. The C-curve means the magnetic trip fires at 5 to 10 times rated current (160–320 A for this 32 A breaker), so it handles motor and transformer inrush without false trips. The 10 kA Icn (rated short-circuit capacity) at 230 V AC is the standard domestic and light-commercial fault level in most European installations; it safely interrupts a bolted fault up to that current without welding the contacts.