What it is and what it does
The Siemens 3RV2031-4EB15 is a SIRIUS motor protection circuit breaker designed to protect three-phase motors against overload and short-circuit. It integrates phase failure detection, so a lost phase trips the breaker before the motor overheats — a common failure mode in industrial lines. Rated 32 A at 600 V and 32 A at 480 V, with a breaking capacity of 30 kA at 400 V AC. That means it can safely interrupt a fault current up to 30,000 A at 400 V without welding contacts or cascading upstream — critical for panel coordination studies. Trip class is CLASS 20, so it allows a 20-second cold-start overload before tripping. That suits standard induction motors driving pumps, fans, and conveyors — not high-inertia loads that need a longer ramp.
Mounting and integration
Mounts via screw or snap-on onto a 35 mm standard mounting rail per DIN EN 60715. Any mounting position is allowed, so it fits tight enclosures without derating. Dimensions: 55 mm wide, 140 mm high, 149 mm deep — check the depth against your enclosure clearance. Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. The storage limit governs handling, not running — fine for unheated warehouses.
Breaking capacity across voltages
Breaking capacity varies with system voltage: 100 kA at 240 V, 30 kA at 400 V, 5 kA at 500 V, and 2 kA at 690 V. The 30 kA at 400 V is the typical industrial panel rating — most distribution boards are designed around that figure.