What this part is and where it goes
The Siemens 3RV2031-4EA15-0BA0 is a SIRIUS motor-protection circuit breaker designed for motor protection duty. It snaps onto a 35 mm DIN rail per DIN EN 60715, so it integrates directly into a standard control-panel layout alongside contactors and overload relays. Rated operating voltage spans 20 to 690 V, and the breaker is rated for a motor output of 7.5 kW at 230 V. The Trip Class 10 characteristic means it will trip within 10 seconds at 7.2× the thermal setting — fast enough to protect standard induction motors during a stall or locked-rotor condition.
Breaking capacity and fault handling
Breaking capacity at 400 V AC is 50 kA, which gives solid headroom for most industrial distribution panels where the prospective fault current is under that level. At 240 V AC it also delivers 50 kA; at 690 V AC the rating drops to 2 kA, so verify the available fault current at the point of installation if running at higher voltages. Phase failure detection is built in — the breaker will trip if one phase drops out, preventing single-phasing damage to the motor. Ground fault detection is not included, so a separate ground-fault relay or RCD is needed if that protection is required.
Dimensions and wiring
The unit measures 149 mm deep by 55 mm wide by 140 mm tall. The 55 mm width is a standard 3-module footprint on a DIN rail, so it occupies three 18 mm slots. Clearance requirements: 50 mm above and below for ventilation, 10 mm at the sides. Main circuit terminals accept screw-type connections — 2×(0.5 to 1.5 mm²) or 2×(0.75 to 2.5 mm²) solid or stranded. The main contact terminal size is M6. Auxiliary contact ratings: 1 A at 24 V, 0.15 A at 60 V, 0.5 A at 230 V. The auxiliary contacts are rated for 0 A at 110 V, 125 V, and 220 V — meaning they are not intended for use at those voltages.