What the ratings mean for fit
The 5SU9336-7CN20 is a combined residual-current circuit breaker with overcurrent protection (RCBO) in a single 1P+N module. The 6 kA breaking capacity (Icn) is the rated short-circuit capacity at 230 V AC — sufficient for most domestic and light commercial distribution boards where the prospective fault current stays under that threshold. The Type A RCD detects sinusoidal AC and pulsating DC fault currents, which covers modern electronics and rectified loads; the 30 mA sensitivity provides supplementary protection against direct contact (30 mA is the standard threshold for personal shock protection per IEC 60364). The C-curve MCB characteristic (magnetic trip between 5× and 10× In) is sized for loads with moderate inrush — think lighting banks, small motors, or control transformers — where the 20 A rated current (In) carries the steady-state load.
Deployment context
The RCBO snaps onto a standard DIN rail inside a consumer unit or sub-distribution board. The 1P+N format protects one line conductor and switches the neutral, fitting the common single-phase final subcircuit layout in IEC markets.