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Live Tank Circuit Breakers

Home > HV/MV Equipment > Circuit Breakers > Live Tank Circuit Breakers

GL 309g, GL 310g, GL 311g and GL 312g
g3 live tank circuit breakers from 72.5 kV up to 145 kV

GE’s GL 309g, 310g, GL 311g and GL 312g live tank circuit breakers for outdoor installation are designed for temperatures down to -30°C. These SF6-free breakers use GE’s g3 to replace SF6 as switching gas. They feature the latest technologies in interrupting chambers and spring-operated mechanisms. They are based on GE’s latest double motion technology which effectively reduces the needed opening energy.

Using g3 instead of SF6 allows GE to keep same performances as SF6 products while reducing the CO2 equivalence of the gas in the equipment by 99%. In addition, thanks to the high dielectric rating of g3, HV products are of the same dimensions. This combination of having a low global warming gas and same quantity of material gives g3 products the lowest environmental impact compared to other SF6-free technologies over the life-time of the equipment. GL 309g, 310g, GL 311g and GL 312g can be delivered as one pole (one spring mechanism per phase) or three pole (one common spring mechanism for the 3 phases) operated circuit-breaker

GE’s live tank circuit-breakers provide a high level of reliability, even under extreme conditions and climates, or in highly active seismic areas. The circuit breakers are completely assembled before delivery, allowing for quick, easy installation and commissioning with long intervals between maintenance. The interrupter chamber can be independently disassembled without having to remove the entire pole column, and the pole units are pre-filled at the factory before shipping.

GE Advantage

High Quality Components

The GL 3109g, GL 310g, GL 311g and GL 312g live tank circuit breakers provide high reliability based on high quality components, including:

  • Interrupter chamber with integral double motion technology and self-blast system
  • Composite insulator and pressure relief system for passive protection of both substation and personnel
  • Field-proven, temperature-compensated density monitor with two-stage transducer and three-color dial
  • Easy access to the g3 filling connection (DILO type with g3 specific thread)
  • g3 non-return (check) valve on each pole column
  • Hot-dip galvanized steel parts
  • Rust free mechanism housing made completely of aluminum
  • Reliable spring-operated mechanism with position indicator clearly visible from outside
  • CBWatch gas monitoring available on request (optional)

Installation, Operation and Maintenance

  • As easy on-site installation as with SF6 CB
  • Preset at factory before shipping; no adjustments necessary during installation and commissioning
  • Pole units pre-filled with g3  at factory before shipping
  • Independent disassembly of the interrupter chamber without having to remove the entire pole column

Advanced Testing

Our live tank circuit breakers meet the requirements of national and international standards. This has been confirmed by comprehensive type tests according to the latest IEC standards.

Certified Quality

The entire development and production procedures for our live tank circuit breakers are fully compliant with the latest ISO 9001, ISO 14001 and OHSAS 18001 quality standards. This ensures the high quality of our products and services, which is confirmed by regular audits.


Breaker type GL 309g F1/4031
GL 309g F3/4031
GL 310g F1/4031
GL 310g F3/4031
GL 311g F1/4031
GL 311g F3/4031
GL 312g F1/4031
GL 312g F3/4031
Rated voltage 72.5 kV 100 kV 123 kV 145 kV
Rated frequency 50 Hz 50 Hz 50 Hz 50 Hz
Rated normal current up to 3,150 A up to 3,150 A up to 3,150 A up to 3,150 A
Rated short-circuit breaking current up to 40 kA up to 40 kA up to 40 kA up to 40 kA
Rated short-circuit making current 104 kA 104 kA 104 kA 104 kA
Rated duration of short-circuit 3 s 3 s 3 s 3 s
Opening time 31 ms 31 ms 31 ms 31 ms
Break time 50 ms 50 ms 50 ms 50 ms
Closing time 100 ms 100 ms 100 ms 100 ms
Average ambient temperature -30 °C up to +40 °C -30 °C up to +40 °C -30 °C up to +40 °C -30 °C up to +40 °C
Design altitude* 1,000 m.a.s.l. 1,000 m.a.s.l. 1,000 m.a.s.l. 1,000 m.a.s.l.

* Standard values according to IEC; Higher design altitudes available on request


GL 309g, 310g, GL 311g and GL 312g

Other dimensions available on request.