The Siemens 3RV2031-4JA15 is a SIRIUS motor protection circuit breaker designed for motor protection, with phase failure detection and a CLASS 10 trip characteristic. It is rated for a breaking capacity of 30 kA at 400 V AC, and can handle motor loads up to 18.5 kW at 230 V. The unit mounts via screw and snap-on onto a 35 mm DIN rail per DIN EN 60715, in any mounting position.
Breaking capacity and coordination
The 30 kA breaking capacity at 400 V AC is the key figure for panel coordination — it tells you this breaker can safely interrupt a fault current up to that level without upstream devices needing to clear it first. At 240 V the interrupting rating rises to 100 kA, and at 690 V it drops to 2 kA. For a site electrical engineer sizing selectivity, the 30 kA at 400 V is the anchor point for the downstream coordination study.
Trip class and motor protection
CLASS 10 trip means the breaker will open within 10 seconds at 7.2× the thermal setting — standard for standard-duty motor starting where the inrush transient is brief. Phase failure detection is built in, so a single-phased motor won't cook before the bimetal catches it. Ground fault detection is not included, so if that's required, an external ground-fault module or relay must be added downstream.
Mounting and clearances
The breaker measures 55 mm wide, 140 mm high, and 149 mm deep. It snaps onto a 35 mm DIN rail per DIN EN 60715, and can also be screw-mounted. Clearance requirements: 50 mm above and below, 10 mm at the sides. For a panel OEM wireman, that 55 mm width is a standard SIRIUS footprint — it occupies one 55 mm slot on the rail, matching the contactor below it for a clean motor starter assembly.