What this SIRIUS breaker does on the line
The Siemens 3RV1031-4DA15 is a SIRIUS motor protection circuit breaker rated for 25 A continuous and 11 kW at 400 V AC-3 duty. That 11 kW figure tells you the motor load it can handle in a standard three-phase 400 V line — sized for a 15 hp (approx.) induction motor, common on pumps, fans, and small conveyors in food-and-bev or packaging lines. That's fast enough to protect a standard squirrel-cage motor from locked-rotor heating without nuisance tripping on normal start-up current. If your line has high-inertia loads that need a slower trip curve, this isn't the breaker for that — CLASS 10 is for general-purpose motor starts. Short-circuit breaking capacity: 100 kA at 240 V AC, 50 kA at 400 V AC, 12 kA at 500 V AC, and 5 kA at 690 V AC. That saves panel space and wiring.
Mounting and wiring — fits the standard rail
Width is 55 mm, height 140 mm, depth 149 mm. That 149 mm depth is a bit deeper than some compact breakers — check your enclosure depth if you're retrofitting into a shallow gland plate. Zero clearance needed at the back or sides for cooling; mounting position is any orientation. Main circuit terminals: screw-type box terminals accepting 2x (0.75 to 25 mm²) stranded or 1x (0.75 to 35 mm²). Solid wire: 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²). AWG equivalents: 2x (18 to 2) or 1x (18 to 2). That's generous — covers most motor feeder cables up to 35 mm² without needing reducers. Auxiliary and control circuit terminals are also screw-type, with transverse auxiliary switch design.
Protection features and compliance
Ground fault detection is not included (no). That's typical for a motor-protective breaker; ground fault is usually handled by a separate RCD or GFCI upstream. Front protection class IP20 — finger-safe when mounted in a closed panel. Rated insulation voltage 690 V. Maximum operating frequency at AC-3 is 15 operations per hour. Substance prohibition date per RoHS: July 1, 2006 — compliant with EU RoHS requirements. No UL or CSA marks in the evidence, but the IEC ratings (EN 50022 rail, IP20, 690 V insulation) align with common international panel standards. If you need specific UL listing for a North American panel, verify that separately.