Motor Protection Circuit Breaker — Siemens SIRIUS 3RV2031-4RA15
The Siemens 3RV2031-4RA15 is a SIRIUS motor protection circuit breaker designed for screw and snap-on mounting onto a 35 mm DIN rail per DIN EN 60715. It is rated for motor protection with phase failure detection and a Trip Class 10, meaning it will trip within 10 seconds under a locked-rotor condition — matching the thermal withstand of standard IEC induction motors during start-up. Breaking capacity is 30 kA at 400 V, which determines whether this breaker can clear a fault without upstream fuses in a given panel SCCR. The rated operational voltage spans 20 to 690 V, covering most low-voltage industrial motor circuits. Mounting position is any; clearance requirements are 50 mm above, 50 mm below, and 10 mm to the side — tight enough for dense DIN-rail layouts in motor control centers.
Dimensions and Panel Fit
Width is 55 mm, depth 149 mm, height 140 mm. The 55 mm width is a standard three-module footprint on 35 mm DIN rail, so it occupies three adjacent 18 mm slots. Verify back-panel depth clearance — the 149 mm projection includes the screw terminals and arc chamber. Main circuit terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded copper, terminated with M6 screws. This covers typical motor feeder sizes up to around 2.5 mm² for a 15 hp motor at 230 V.
Lifecycle and Sourcing
Operating temperature range is -20 to +60 °C, storage and transport range is -50 to +80 °C. This covers most indoor industrial environments without derating.