It provides both earth leakage and short-circuit/overload protection for a single-phase final subcircuit. The Type A residual-current detection handles pulsating DC faults and sinusoidal AC — covers modern electronics and switched-mode power supplies common in lighting and appliance circuits.
The 30 mA residual sensitivity is the standard for personal protection against electric shock in socket-outlet circuits per IEC 60364. The 1P+N format switches the phase only and breaks the neutral without switching it — typical for single-phase final circuits in TN or TT earthing systems.