The Siemens 3RV1021-0FA10 is a SIRIUS motor protection circuit breaker rated for 0.5 A continuous current with Trip Class 10 thermal overload protection. It breaks up to 100 kA at 400 V AC, which means it handles high fault currents without cascading upstream — useful when the panel SCCR requirement is stiff and you're feeding a small motor or transformer.
Mounting and fit
Snaps onto 35 mm DIN rail per EN 50022, 45 mm wide, 97 mm tall, 96 mm deep. Screw terminals on both main and auxiliary circuits. Accepts solid or stranded copper: 2x (1…2.5 mm²) or 2x (2.5…6 mm²) per clamp. Zero overhang backwards or at the side — sits flush on the rail, which keeps the gland plate layout predictable.
Protection and ratings
Phase failure detection is built in; ground fault detection is not. Rated for 690 V max (AC-3), 6 kV surge withstand. Operating frequency tops at 15 operations per hour at AC-3. Shock rated 25g / 11 ms. IP20 on the front — fine inside a closed panel, not for washdown zones. Storage temp -50 to +80 °C; operating -20 to +60 °C.