SIRIUS S2 motor protection circuit breaker — 3RV2031-4UB10-0BA0
The Siemens 3RV2031-4UB10-0BA0 is a SIRIUS motor protection circuit breaker in the S2 frame size, designed for protecting three-phase motors against overload and short-circuit. It delivers 11 kW at 230 V and carries a Trip Class 20 characteristic, meaning it allows a 20-second thermal trip at 7.2× rated current — suited for motor starts with moderate inertia like pumps and compressors. Rated operational voltage spans 20 to 690 V. Breaking capacity at 400 V reaches 25 kA (50 kA at the same voltage for the AC variant), which covers most industrial distribution panels. At 690 V the breaking capacity drops to 2 kA (6 kA AC) — verify the available fault current at the point of installation. Phase failure detection is built in, so the breaker will trip on loss of one phase — a common failure mode in motor circuits that can cause single-phasing damage. No ground-fault detection on this variant.
Mounting and integration
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The S2 frame occupies 55 mm width, 140 mm height, 149 mm depth — a standard footprint that fits alongside SIRIUS contactors in a motor starter lineup. Mounting position is any orientation. Clearance requirements: 50 mm upwards and downwards, 10 mm at the sides. No additional fuse is required at 240 V; at 400 V the upstream fuse is gG 125 A, at 500 V gG 100 A, at 690 V gG 80 A. Screw-type terminals for the main circuit accept 2× (1 to 25 mm²) or 1× (1 to 35 mm²) solid or stranded copper. The screwdriver shaft diameter is 5 to 6 mm, Pozidriv size 2 tip. Main contact screws are M6.