The Siemens 3RV1031-4BA15 is a SIRIUS motor protection circuit breaker rated for 20 A continuous current and 7.5 kW at 400 V AC-3, making it the right thermal-magnetic fit for a 7.5 kW motor on a 400 V three-phase line.
Breaking capacity and fault clearing
At 240 V it clears 100 kA; at 500 V it drops to 12 kA, and at 690 V to 5 kA. For a panel fed by a transformer with a 50 kA prospective short-circuit current at 400 V, this breaker alone handles the fault — no series fuse coordination needed.
The main circuit uses screw-type box terminals; stranded wire from 0.75 to 35 mm² single or 2× 25 mm² fits. Auxiliary and control circuit terminals accept solid 0.5 to 2.5 mm² or stranded 0.75 to 2.5 mm². Zero clearance at the sides and rear means no extra air gap between adjacent breakers — the 55 mm width per pole is the only space consumed. IP20 on the front protects against finger contact; the interior of the panel must provide the rest of the enclosure rating.