What this RC unit is for
The Siemens SENTRON 5SM9346-0 is a residual current unit (RC unit) designed to mount below a 5SL4 miniature circuit breaker, forming a combined RCBO. It is a 4-pole, type AC device rated at 63 A and 30 mA tripping current at 400 V AC.
Rated at 63 A AC and 30 mA residual tripping current, this unit handles full-load circuits up to 63 A while providing ground-fault protection at 30 mA — the standard threshold for personal protection against electric shock. The 400 V AC rated voltage suits three-phase 4-wire systems (L1, L2, L3, N) common in European industrial and commercial panels. The unit accepts solid conductors from 0.75 to 35 mm² and stranded conductors from 0.75 to 25 mm², with a tightening torque of 2.5 to 3 N·m. That range covers most distribution wiring up to 35 mm² — enough for a 63 A feeder on a 400 V system.
The supply cord connects at the top, above the miniature circuit breaker. Installation depth is 70 mm, matching the depth of the 5SL4 breaker it pairs with.