The Siemens 3RV2021-0JA10-0DA0 is a SIRIUS 3RV2 motor starter protector in size S0, designed for system protection without phase failure protection. The A-release adjustable from 0.7 to 1 A sets the overload trip threshold for the motor's full-load current — set it to match the motor nameplate FLA, not the breaker's maximum. The fixed short-circuit release at 13 A clears bolted faults fast enough to protect the downstream contactor and cable, so selectivity with an upstream feeder breaker depends on that 13 A magnetic trip being lower than the feeder's instantaneous pickup. Screw terminals and standard switching capacity keep this a direct swap for existing S0-frame installations. The 3RV2 family covers motor protection from fractional to about 15 kW at 400 V; this variant sits in the lower end of that range, sized for small pumps, fans, or conveyor drives drawing under 1 A full-load.
RoHS compliance dates from October 1, 2009, and REACH candidate-list information is published by Siemens — standard regulatory documentation for EU-market installations. No UL or CSA listing is stated in the evidence, so verify site-specific approval requirements separately if the panel requires third-party certification.
Size S0 mounts on DIN rail in a standard control panel — the 102 x 49 x 102 mm footprint matches the S0 cutout and rail spacing used across the SIRIUS 3RV2 range. Screw terminals accept copper conductors typical for motor circuits at this current level; torque to the values printed on the device side. No phase-failure protection means the breaker relies on the upstream supply or a separate phase-monitoring relay if single-phasing is a risk on the line.