Siemens Circuit breaker for transformer protection, size S0, 325AProduct Overview The SIRIUS 3RV2 circuit breaker is a specialized, high performance circuit breaker designed specifically for transformer protection with full UL 489 and CSA C22. 2 No. 5 02 approval. This frame size S0 circuit breaker features thermal overload release at 20A and short circuit release at 325A with screw terminal connections and standard switching capacity, optimized for transformer protection applications. Key Features This circuit