The Siemens 3RV2031-4KA10-ZX95 is a SIRIUS motor protection circuit breaker, designed to protect motors against overload and short-circuit. It carries a Class 10 trip characteristic, which means it will trip within 10 seconds at 7.2× rated current — fast enough to protect standard induction motors during a locked-rotor event without nuisance tripping on normal starting inrush. Rated for motor duty at 22 kW at 230 V, 20 hp at 200/208 V, 25 hp at 220/230 V, and 50 hp at 460/480 V, this breaker covers a broad range of three-phase motor sizes commonly found on pumps, conveyors, and fans in industrial panels.
Breaking capacity and coordination
The interrupting ratings are voltage-dependent: 65 kA at 240 V, 30 kA at 400 V, 5 kA at 500 V, and 2 kA at 690 V. At 400 V — the most common industrial supply in Europe and much of Asia — the 30 kA figure gives solid headroom for most panel SCCR requirements. At 690 V the 2 kA rating is lower; if your fault current at that voltage exceeds 2 kA, you'll need an upstream current-limiting device to coordinate. Phase failure detection is built in, so a lost phase on the line side will cause the breaker to trip — critical for preventing single-phasing damage on delta-connected motors. There is no ground-fault detection, so if you need that, plan on an external GF relay.
Mounting and wiring
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The 55 mm width and 149 mm depth are standard for this SIRIUS frame size. Clearance requirements: 50 mm above and below, 10 mm to the side, zero forward or backward. That means you can pack breakers side-by-side without side gaps, but you need breathing room top and bottom for heat dissipation and arc clearance. Screw-type terminals on the main circuit accept 2×(1–35 mm²) or 1×(1–50 mm²) solid or stranded copper. Torque to M6. That's generous wire range — covers everything from control-circuit taps up to motor feeder cables for a 50 hp motor.
Environmental and lifecycle
Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. The temperature compensation is also rated -20 to +60 °C, so the thermal trip curve stays accurate across the full operating band — important if this breaker sits in a hot panel near a motor or in an unconditioned enclosure.