The Siemens 5SM1346-6BA is a Type A residual-current device (RCD) — an FI protector — rated 63 A, 4-pole, with 30 mA sensitivity at 400 V. The 30 mA trip threshold means it provides supplementary protection against lethal shock in personnel-contact scenarios, not just equipment ground-fault. The 63 A continuous rating suits it for a main or submain RCD on a 3-phase distribution board feeding mixed loads.
Deployment context
The Type A designation covers pulsating DC fault currents and AC sinusoidal — typical for circuits with rectifiers, switching power supplies, or single-phase electronics where pure AC-only RCDs might blind-trip or fail to trip.