What it is and what it does
The Siemens 3RV1031-4FA15-ZX95 is a SIRIUS motor protection circuit breaker designed for motor protection in industrial control panels. It provides overload and short-circuit protection for motors up to 18.5 kW at 400 V AC, with a continuous current rating of 40 A and a CLASS 10 trip characteristic — meaning it will trip within 10 seconds at 7.2× rated current, which is the standard for protecting standard induction motors during start-up.
Breaking capacity and coordination
Rated breaking capacity varies with supply voltage: 100 kA at 240 V AC, 50 kA at 400 V AC, 10 kA at 500 V AC, and 4 kA at 690 V AC. The 50 kA at 400 V AC is the figure most relevant for European 400 V three-phase panels — it means the device can safely interrupt a fault current up to 50 kA without upstream fuses or breakers needing to clear first, which simplifies selectivity coordination.
Mounting and integration
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 50022. Any mounting position is permitted. Dimensions: 55 mm wide, 140 mm high, 149 mm deep. The 149 mm depth is the full body depth including terminals — check clearance behind the panel door if using a shallow enclosure. IP20 on the front (finger-safe), so it suits enclosed panel installation, not washdown environments.
Auxiliary and control circuit ratings
The auxiliary switch (transverse design, field-installable) is rated 1 A at 24 V, 0.5 A at 230 V, and 0.15 A at 60 V. These are the maximum switching currents for the auxiliary contacts — useful for feeding a PLC input or a status lamp. The main circuit uses screw-type box terminals accepting 2x (0.75 … 25 mm²) stranded or 1x (0.75 … 35 mm²) stranded; the auxiliary circuit uses separate screw terminals accepting 2x (0.5 … 1.5 mm²) solid or 2x (0.75 … 2.5 mm²) solid.
Sourcing posture
This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time. For a BOM line that calls out 3RV1031-4FA15-ZX95, the active lifecycle and standard DIN-rail footprint mean no redesign is needed — it drops straight into the panel.