Circuit breaker size S0 for transformer protection A-release 3.5...5 A N-release 10...40 A screw connection. Standard switching capacity circuit breakers SIRIUS 3RV2 for transformer protection to ensure safe protection of transformers against short circuits and overloads. The compact and climate-resistant circuit breakers are optimized for use in consumer branches due to their low heat dissipation, and are naturally suitable for IE3/IE4 motors as well as for switching direct current. Worldwide approvals, such as IEC and UL/CSA, and applications in explosion-prone environments (ATEX or IEC Ex) are standard. Device variants are available for motor protection (also with overload relay function), plant protection, short circuit protection of starter combinations, transformer protection, as main and emergency stop switches, and for use in IT networks. They come with screw or spring terminals for quick, maintenance-free, and vibration-resistant connections, and optionally with an integrated auxiliary switch. The comprehensive accessories, such as auxiliary switches, auxiliary releases, signaling switches, etc., are uniform for all sizes. The use of various power supply options, such as the associated power supply system SIRIUS 3RV29, significantly reduces the main circuit wiring. The 3RV2 circuit breakers replace the proven series 3RV1. Simple, efficient, always up to date - the SIRIUS system modular concept.