Siemens 3RV1421-1JA10 is a three-pole Sirius motor protection circuit breaker (size S0) designed for transformer protection and 690 V systems, with a nominal current rating of 7–10 A. It combines thermal-magnetic protection with a short-circuit release rated around 208 A and can be equipped with an auxiliary switch; main circuit connections use screw terminals. The front enclosure is IP20 protected, and the device is designed for installation at elevations up to 2,000 meters above sea level. As part of the Siemens Sirius 3RV14 family, it serves as a compact protective device for motors and transformers in industrial control panels.
