SIRIUS 3RV1342-4DC10 — Motor Circuit Breaker for Starter Combinations
The Siemens 3RV1342-4DC10 is a SIRIUS circuit breaker designed specifically for starter combinations, providing motor and short-circuit protection in a single device. It carries a continuous rated current of 25 A and is rated for 11 kW motor power at 400 V AC-3 duty, which means it directly protects a motor load of that size without an additional fuse upstream for coordination type 1 or 2, depending on the upstream breaker. Breaking capacity is 100 kA at 240 V and 400 V AC, dropping to 30 kA at 500 V and 12 kA at 690 V. At 690 V the rated voltage maximum for AC-3 operation, the device still clears 12 kA — sufficient for most industrial distribution panels where the fault current at the motor branch is typically lower than at the main bus. The 100 kA at 400 V means this breaker can be installed downstream of a transformer with high fault current without requiring a current-limiting fuse ahead of it, simplifying panel layout. Mounting is via screw and snap-on onto a 35 mm DIN rail per EN 50022, with zero clearance required at the back or sides — no derating for side-by-side installation in a crowded enclosure. The IP20 front protection means it is finger-safe from the front but not sealed against dust or moisture; it belongs in a panel, not in a washdown zone. Terminals are screw-type with box terminals for the main circuit, accepting 2x (2.5…16 mm²) solid or 2x (10…50 mm²) stranded, with a single conductor up to 70 mm² stranded. This wire range covers standard motor feeder cables from 2.5 mm² for small motors up to 50 mm² for the 25 A rating, with headroom for parallel feeds. Auxiliary and control circuits also use screw terminals, consistent with the main circuit.
Lifecycle & Sourcing
Compliance documentation includes RoHS substance prohibitance dated July 1, 2006, indicating the part meets the EU RoHS directive for lead, mercury, cadmium, and other restricted substances. The part carries no ground fault or phase failure detection — it is a straight thermal-magnetic motor circuit breaker, not a multifunction electronic protector.
Integration Notes
Dimensions are 70 mm wide, 165 mm high, 174 mm deep. The 70 mm width is three 18 mm module spaces on a DIN rail, matching the footprint of a standard 3-pole motor circuit breaker. The 174 mm depth includes the screw terminals and any protruding conductors — ensure 200 mm clearance in front of the rail for wiring access. Power dissipation is 21 W total in hot operating state, or 7 W per pole. In a sealed enclosure with multiple devices, this heat must be considered for thermal management; forced ventilation or a larger enclosure may be needed if several breakers are ganged. Operating frequency is limited to 15 switching operations per hour at AC-3 maximum. This is typical for a motor circuit breaker — it is not designed for frequent switching like a contactor. For applications requiring more than 15 starts per hour, use a contactor for the switching duty and the breaker only for protection. Shock resistance is 25g for 11 ms, adequate for most industrial environments including conveyor systems and machine tools. The device can be mounted in any position, simplifying panel layout.