The Siemens Circuit breaker size S00 for transformer protection A-release 5.5…8 A N-release 163 A Spring-type terminal Standard switching capacity Circuit breaker SIRIUS 3RV2 For transformer protection for the reliable protection of transformers against short-circuit and overload. Thanks to their low heat loss, the compact and climate-resistant circuit breakers are optimized for use in load feeders, and also for IE3/IE4 motors, of course, and equally for the switching of direct current. Worldwide approvals (e.g. IEC and UL/CSA) and applications in hazardous areas (ATEX or IEC Ex) are a matter of course.