The 5SM3347-4BG is a 4-pole Type B residual current circuit breaker (RCCB) rated 80 A and 30 mA sensitivity on a 400 V AC system. The Type B characteristic detects smooth DC fault currents and high-frequency AC — common in VFD-fed motors, UPS systems, and EV charging stations where a standard Type A or AC RCCB would be blind to DC fault components. The short-time delayed (S-type) rating means it withstands short inrush without nuisance tripping, so it coordinates downstream on a distribution board feeding motor starters or drives. The 80 A rating covers the incomer for a sub-panel or a large single load; the 30 mA trip threshold provides personnel protection (touch-current limit per IEC 60364).
Deployment context
Mounts on standard DIN rail inside a panel enclosure. The 4-pole format connects L1, L2, L3, and N; the Type B detection coil monitors all conductors including the neutral for residual current. In a typical motor control centre fed by a VFD, this breaker sits at the sub-distribution board ahead of individual drive feeds — the S-type delay prevents it dropping out on drive capacitor charging current.