Siemens 3RV1021-0KA10 Molded Case Circuit Breaker

Siemens 3RV1021-0KA10 is a three‑pole molded‑case circuit breaker (size S0) intended for motor protection in 3‑phase power circuits. It provides a thermal‑magnetic release with Class 10 trip characteristics and an adjustable thermal release setting from 0.9 to 1.25 A, complemented by an instantaneous short‑circuit release rated at 16 A. Designed for DIN rail mounting, it uses screw‑terminal connections for reliable panel wiring and is suitable for 220–690 V AC three‑phase systems, with typical motor ratings around 0.37 kW at common line voltages. Siemens lists this model as no longer available and notes the preferred successor in the Sirius 3RV2 family as 3RV2011-0KA10. The device is intended for motor protection in control panels and motor control centers, delivering overload protection for small motors while maintaining compatibility with legacy Siemens equipment and the 3RV form factor.