What this part is and what it does
The Siemens 3RV1031-4GB10 is a SIRIUS motor-protection circuit breaker rated for 45 A continuous current with a CLASS 20 trip characteristic, sized for a 22 kW motor at 400 V. It snaps onto a 35 mm DIN rail per EN 50022 and uses screw-type box terminals for the main circuit — 2x (0.75…16 mm²) solid or 2x (0.75…25 mm²) stranded, with a single conductor up to 35 mm² stranded. The 50 kA interrupting rating at 400 V AC means this breaker can clear a bolted fault up to that level without upstream fuses needing to open — useful for high-fault panels where you want to keep selectivity simple. At 690 V the SCCR drops to 4 kA, so verify the available fault current if you're running a 690 V line.
Trip class and protection logic
CLASS 20 means the bimetal trip allows up to 20 seconds at 600% of the full-load current before opening — standard for general-purpose induction motors driving pumps, fans, and compressors where the start-up transient isn't extreme. Phase-failure detection is built in, so a lost phase on the line side will trip the breaker rather than let the motor single-phase and burn. No ground-fault detection here; if you need that, you'd add a separate ground-fault module or use a different frame.
Panel fit and wiring
The 3RV1031-4GB10 occupies 55 mm width on the DIN rail, with 149 mm depth and 140 mm height. Zero clearance needed at the back or sides — you can butt it against other devices without derating spacing. The screw terminals accept AWG 18…2 for the main circuit. Power dissipation runs 29 W total (9.7 W per pole) in hot operating state — factor that into enclosure thermal calcs if you're packing several breakers in a small box.
Environmental and compliance
Operating temperature range is -20 to +60 °C; storage and transport handle -50 to +80 °C. The front face carries IP20 protection — suitable for a closed panel, not for washdown. Shock rated at 25 g / 11 ms. RoHS compliance date is July 1, 2006, so it meets the EU directive.