The Siemens SENTRON 5SM3748-6 is a 4-pole residual current circuit breaker (RCCB), Type A, rated at 100 A with a 500 mA trip threshold on a 400 V AC, 50 Hz supply. It carries a 10 kA short-circuit current rating per IEC 61008-1 and a 1 kA rating per EN 60898 — the lower figure governs selectivity with downstream MCBs in a residential or commercial distribution board. The 500 mA trip suits it for fire-protection or equipment-protection duty rather than personal shock protection (which typically requires 30 mA or lower).
Mounting and panel fit
Snap-on DIN rail (REG) mounting, 4 modular width units (72 mm wide). Depth is 77 mm with a 70 mm installation depth behind the panel surface. Mounting position is unrestricted — horizontal, vertical, or inverted — which simplifies layout in a crowded enclosure. IP20 rating applies once installed with conductors connected; the distribution board itself provides the enclosure seal.