The Siemens 3RV2031-4EA15-ZW96 is a SIRIUS motor protection circuit breaker — the class of device that combines a contactor with overload and short-circuit protection in one DIN-rail package. It's designed for motor protection, meaning it handles the inrush and running load of a three-phase motor and trips on a locked-rotor or fault condition before the motor windings cook. Rated breaking capacity hits 30 kA at 400 V AC — that's enough to clear a hard fault on most industrial distribution without the upstream breaker having to coordinate. Trip class is CLASS 10, so it disconnects within 10 seconds at seven times the thermal setting, fast enough for standard motor starts but not so fast it nuisance-trips on normal acceleration.
Mounting and panel fit
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715 — the standard rail in every panel I've ever opened. Any mounting position works, so you can orient it to fit the gland plate or busbar layout. Dimensions are 149 mm deep, 55 mm wide, 140 mm tall; that 55 mm width is a single-module footprint on the rail, leaving room for the contactor and overload block alongside. Clearance requirements: 50 mm upward and downward, 10 mm at the sides. That upward gap matters if you're stacking breakers in a tight enclosure — the arc chute needs that space to vent hot gases. No forward clearance needed.
Ratings and what they mean in the field
Main contact terminal size is M6 — takes 2x (0.5 to 1.5 mm²) solid or stranded, or 2x (0.75 to 2.5 mm²). Rated value spans 20 to 690 V. Breaking capacity varies with voltage: 100 kA at 240 V, 30 kA at 400 V, 5 kA at 500 V, 2 kA at 690 V. At 480 V it's rated 32 A continuous — that's the same current as the 600 V rating. The 30 kA at 400 V is the number most integrators will check first for a standard 400 V MCC. Operating temperature range is -20 to +60 °C; storage and transport handle -50 to +80 °C.
Lifecycle status is current production — no end-of-life notice on this order code. That means it's still the active design, not a phase-out or NRND part. Sourcing is straightforward: it's quoted to order against an RFQ through independent distribution, with availability and current pricing confirmed at quote time.