Siemens 5SU1353-7KV25 FI/LS Protector, Type A, 30mA, 25A C-c

The 5SU1353-7KV25 is a combined residual-current device (RCD) and miniature circuit breaker (MCB) — an FI/LS protector — in a single 1+N-pole unit. The Type A designation means it detects both sinusoidal AC fault currents and pulsating DC fault currents, which covers modern electronics and variable-speed drives that can generate pulsed DC leakage. The 30 mA sensitivity is the standard for personal protection against electric shock (per IEC 60364). The C-curve (25 A rated current) trips at 5–10× In, so it handles motor and lighting inrush without nuisance tripping while still protecting against short circuits.