The Siemens 3RV1021-1EA15 is a SIRIUS motor protection circuit breaker rated for 4 A continuous current with a Class 10 trip characteristic. It's designed for motor protection in control panels, with a 100 kA breaking capacity at 400 V AC — that's the fault-clearing ability that keeps upstream gear safe during a short circuit. Phase failure detection is built in, so a lost leg won't let the motor single-phase to destruction.
Mounting and integration
Snaps onto 35 mm DIN rail per DIN EN 50022, or screws directly to a backplate. The 45 mm width means it takes one standard module slot in a panel — no surprises when laying out a row of breakers. IP20 on the front, so it's protected against finger contact once the panel door is closed.
Key ratings and what they mean
The 4 A continuous rating sets the motor FLA it can carry without nuisance tripping. Class 10 trip means it will disconnect within 10 seconds at 7.2× rated current — fast enough for most standard induction motor starts, but verify against your motor's start profile if it's a high-inertia load. Breaking capacity holds at 100 kA up through 500 V AC, dropping to 6 kA at 690 V AC; at 400 V, that 100 kA covers virtually any industrial fault level you'll find downstream of a distribution transformer. The 1.5 kW motor power rating at 400 V gives a quick sizing reference for three-phase squirrel-cage motors.
Termination and wiring
Screw-type terminals on both main and auxiliary circuits. The main circuit accepts solid conductors from 0.5 to 1.5 mm² (two per clamp) or 0.75 to 2.5 mm² (two per clamp); stranded goes up to 2.5 mm² (two per clamp) or 2.5 to 6 mm² (two per clamp). That covers most motor branch circuit wiring up to about 4 mm² for the feed. Auxiliary switch contacts are rated 1 A at 24 V, 0.5 A at 230 V, and 0.15 A at 60 V — enough for a PLC input or a contactor coil.