The Siemens 3RV6021-4BA15 is a SIRIUS motor protection circuit breaker, size S0, rated for 20 A operational current at 690 V AC-3. The magnetic short-circuit release handles fault clearing independently. Clearance requirements: 50 mm upwards and downwards, 30 mm at the sides, zero forwards or backwards. Screw-type terminals on both main and auxiliary circuits accept 2x (0.5…1.5 mm²) solid/stranded or 2x (0.75…2.5 mm²) with ferrules; AWG equivalents 2x (16…12) and 2x (14…8) for main contacts.
Rated operational current of 20 A at AC-3 governs motor sizing — pair this breaker with a motor whose full-load current does not exceed 20 A. The 690 V rated insulation voltage and 6 kV surge voltage resistance cover industrial transient environments. The magnetic short-circuit trip responds instantaneously to fault currents, providing Type 2 coordination with upstream contactors when properly selected. Typical power loss of 8 W total — relevant for thermal management in densely populated enclosures. Operating temperature range -20 to +60 °C with 10-95% relative humidity; storage range -50 to +80 °C. Shock resistance 25g / 11 ms per IEC 60068-2-27.
Integration & Compliance
The 3-pole design (3 main poles) with transverse auxiliary switch configuration allows integration of early-warning or trip-indication contacts into the control circuit. Screw terminals with tightening torque 2…2.5 N·m for main contacts. Substance prohibitance date of 05/01/2012 aligns with RoHS and REACH compliance timelines. The IEC ratings (surge voltage, shock, humidity) indicate design for international standards compliance.