Type B Selective RCCB for 400 V Three-Phase Feeders
The Siemens 5SM3647-5BG is a 4-pole residual current operated circuit breaker (RCCB) rated for 80 A continuous load at 400 V AC, with a 300 mA trip sensitivity and type B, selective response curve. Type B detection covers AC, pulsating DC, and smooth DC fault currents up to the rated frequency — essential where variable-speed drives, UPS systems, or rectifier loads generate smooth DC leakage that standard AC/type A RCCBs cannot sense. The selective (time-delayed) characteristic coordinates with downstream 30 mA RCDs, letting the feeder RCCB ride through transient earth faults without nuisance tripping while the branch device clears a sustained fault first. DIN-rail mount, 4-pole width for panel integration.