What this breaker does in a motor circuit
The Siemens 3RV1021-1GA15-ZX95 is a SIRIUS motor protection circuit breaker rated for 6.3 A continuous current, sized to protect a 2.2 kW motor on a 400 V three-phase line. It carries a CLASS 10 trip characteristic, meaning it will disconnect within 10 seconds at 7.2x the thermal setting — fast enough to keep a locked-rotor condition from cooking the windings on a standard squirrel-cage motor. Phase failure detection is built in, so if one leg drops out on a delta-connected motor, the breaker trips instead of letting the motor single-phase and overheat. That's the kind of thing you want on any pump, conveyor, or compressor circuit where a lost phase would mean a rewind bill. Breaking capacity runs 100 kA at 240 V, 400 V, and 500 V AC, dropping to 6 kA at 690 V. That 100 kA figure means it can safely interrupt a bolted fault at the panel's main bus level without welding its contacts shut — important when this breaker sits downstream of a transformer or a high-capacity distribution board.
Mounting and wiring on the rail
Snaps onto 35 mm DIN rail per DIN EN 50022, screw and snap-on fastening. No tools needed for the rail; the screw terminals on both main and auxiliary circuits take solid wire from 0.5 to 1.5 mm² (two conductors per clamp) and stranded from 1.0 to 2.5 mm², with a second range up to 6 mm² for larger feeds. For AWG, main contacts accept 2x (14 to 10). The auxiliary switch is designed transverse and the product extension allows adding a separate auxiliary contact block if the built-in contacts aren't enough for your PLC feedback or status lamp. Mounting position is any orientation, and the breaker is rated for 25g shock at 11 ms — it'll hold up on a vibrating conveyor panel or a compressor skid without nuisance tripping from mechanical shock.
Environmental and compliance notes
Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. The IP20 front protection means it's suitable for installation inside an enclosed panel, not for washdown or outdoor exposure without an additional enclosure. RoHS compliance date is marked as 01.05.2012, indicating the product has been compliant with the RoHS directive since that date. Ground fault detection is not included — this is a motor protection breaker, not a residual-current device. Power dissipation in hot operating state is 7.25 W at rated current — factor that into your enclosure thermal budget if you're packing several of these on a rail.