The Siemens 3RV1031-4GA10 is a SIRIUS motor protection circuit breaker rated for 45 A continuous current with a Class 10 trip characteristic. It's built for 3-phase motor circuits up to 22 kW at 400 V AC. Breaking capacity runs 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 — so on a 400 V line you've got plenty of headroom for high-fault panels. It snaps onto a 35 mm DIN rail per EN 50022 and can be mounted in any position. The screw-type box terminals on the main circuit accept up to 35 mm² stranded, and there's room for an auxiliary switch. Phase failure detection is built in; ground fault detection is not. Front IP20 keeps fingers out of the live terminals.
What the ratings mean on the line
Class 10 trip means the breaker will open within 10 seconds at 7.2× rated current — that's the standard for protecting standard squirrel-cage motors during a stall or locked-rotor condition. A slower class (e.g. Class 20) would let the motor cook longer; a faster one (Class 5) might nuisance-trip on start-up inrush. The 45 A continuous rating and 22 kW at 400 V match up with a 45–50 A motor full-load current on a 400 V supply. If your motor nameplate says 48 A FLA, this breaker is sized right.
Lifecycle and sourcing reality
If you're filling a BOM line or replacing a failed unit on a live panel, this is the current-production direct fit. Availability and current pricing are confirmed at quote time against an RFQ.
Panel fit and wiring
Width is 55 mm, height 140 mm, depth 149 mm — that's a standard 3-pole MCCB footprint on DIN rail. Zero clearance needed at the back or sides for heat dissipation. Terminals accept 2x (0.75–16 mm²) solid or 2x (0.75–25 mm²) stranded, plus a single up to 35 mm² stranded. That covers most motor circuit feeds up to around 10 mm² per phase; for larger conductors you'd step up to the next frame size. Finger-safe touch protection (IP20 front) means the panel builder doesn't need additional covers over the terminals for basic shock protection.