SIRIUS 3RV2 Circuit Breakers Siemens SIRIUS 3RV2 Circuit Breakers are motor starter protectors that reliably protect equipment during a short circuit. When a short-circuit event (>,13 times the rated current) occurs, the short-circuit releases isolate the faulty load feeder from the power supply within milliseconds. This quick response avoids fire damage and other significant harm to components. Siemens SIRIUS 3RV2 Circuit Breakers feature a lockable operating mechanism for manual closing/opening that prevents unauthorized access and ensures trouble-free operation. These motor starter protectors come in various sizes and are designed for flexible assembly using screw and spring-type terminals. These circuit breakers cover all the tasks of protecting motors, starters, transformers, and UL 489 applications.