What it is and what it does
The Siemens 5SU1356-7KV32 is a combined residual-current device and miniature circuit breaker — an RCBO — in a single 1+N-pole module. It's listed as Type A (sensitive to pulsating DC fault currents up to 6 mA), with a rated residual current IΔN of 30 mA and a short-circuit breaking capacity of 6 kA. The thermal-magnetic trip curve is C, rated 32 A. That means it protects a final subcircuit against both earth faults and overload/short-circuit, all in one DIN-rail unit.
What the ratings mean for fit
The 30 mA IΔN is the standard threshold for personal protection against direct contact — it's what you spec for socket-outlet circuits, lighting final circuits, and general-purpose power in residential and light commercial panels. The 6 kA breaking capacity (Icn) is adequate for most domestic and small commercial installations where the prospective short-circuit current at the board is under 6 kA. The C-curve (32 A) means the magnetic trip operates at 5 to 10 times rated current, so it's a good fit for circuits with moderate inrush — think small motors, pumps, or groups of fluorescent lighting — without nuisance tripping on start-up.