GMSG Vacuum Circuit Breaker

Why GMSG Vacuum Circuit Breaker?

GMSG vacuum circuit breakers are drawout medium-voltage circuit breakers designed for use in Siemens GM-SG and GM-SG-AR metal-clad switchgear. The breaker uses vacuum interrupters with a stored-energy operator, electrical controls, interlocks, and primary and secondary disconnects. With voltage ratings from 5 kV to 27 kV, interrupting ratings to 63 kA, and continuous current ratings up to 3000 A (increased capabilities with fan cooling in applicable switchgear configurations). GMSG vacuum circuit breakers support reliable switching, simplified maintenance access, and coordinated application in medium-voltage power distribution systems.

Key benefits

Simplify maintenance

The front-mounted operating mechanism is readily accessible to support inspection, and maintenance to reduce service complexity. No lift truck is needed to insert or remove GMSG circuit breakers in the lower cells at floor level.

Enhance safety

Improved operator safety with vacuum interruption technology, integrated interlocks, and compatibility with the Siemens Integrated Electrical Racking System (SIERS) for remote breaker racking.

Standardize operations

A common stored-energy operator across Siemens MV breaker families simplifies training and maintenance, while interlock logic enables a single spare breaker to support multiple applications, simplifying spare-parts management.

Featured capabilities

Broad range of ratings

Available with voltage ratings from 5 kV to 27 kV, interrupting ratings up to 63 kA, with continuous current ratings up to 4,000 A (in specific configurations), supporting a wide range of medium-voltage distribution applications.

Proven vacuum switching technology

Leverage Siemens vacuum interrupters for reliable switching performance and long service life.

Drawout design with integrated interlocks

GMSG circuit breakers use drawout construction, with automatic and self-aligning primary and secondary disconnects, and racking interlocks to support safe and reliable operation within GM-SG and GM-SG-AR switchgear.