What the ratings mean for your panel
The 5SU9346-7CR40 is a 1P+N RCBO combining overcurrent protection and residual current detection in a single DIN-rail module. Its 6 kA breaking capacity (Icn) at 230 V AC means it can safely interrupt a fault current up to that level without welding its contacts or cascading damage upstream — adequate for most domestic and light commercial final circuits where the prospective short-circuit current stays under that threshold. The Type A RCD element (30 mA sensitivity) detects sinusoidal AC residual currents plus pulsating DC residual currents up to 6 mA smooth DC superimposed — the standard choice for circuits with single-phase rectified loads like washing machines, LED drivers, or small VFDs. The C-curve (40 A In) means the magnetic trip fires at 5 to 10 times rated current (200–400 A), so it holds through motor inrush and capacitive loads without nuisance tripping.