What it is and what it does
The Siemens 3RV2031-4EA10-ZX95 is a SIRIUS motor protection circuit breaker designed for motor protection. Trip Class 10 means it trips within 10 seconds at 7.2× the thermal setting — standard for protecting standard 4-pole induction motors against overload and stall conditions. Phase failure detection is built in, so a lost phase on the line side shunts the motor off before single-phasing cooks the winding.
Mounting and integration
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The 55 mm width matches the standard SIRIUS 3RV2 footprint — slides into a panel alongside a 3RT2 contactor without adapters. Any mounting position is allowed, so vertical or horizontal busbar runs work. Terminal capacity: accepts up to 2× 25 mm² or 1× 35 mm² solid or stranded at the main contacts, with M6 screw-type terminals for the main current circuit.
Breaking capacity and clearances
Breaking capacity: 100 kA at 240 V, 30 kA at 400 V, 5 kA at 500 V, 2 kA at 690 V. That 30 kA at 400 V is the number most panel builders check — it clears faults up to that level without upstream fuses in most 400 V distribution boards. Required lateral clearance: 10 mm at the side, 50 mm upwards, 50 mm downwards, 0 mm forwards and backwards. At 240 V no clearance is required. Depth is 149 mm, height 140 mm, width 55 mm.