SecoRMU - Secondary Distribution Gas Insulated Switchgear

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SecoRMU gas insulated ring main unit is a compact, modularized, extendable or fixed gas insulated ring main unit with the primary conductive system sealed in a stainless SF6 gas tank, providing customers a safe, reliable, high-performance and maintenance-free product.

SecoRMU provides integrated solutions for most switching applications in urban-rural power cable upscale, power distribution network, wind farm, industry, O&G, underground installation, as well as municipal construction, commercial buildings, residential and other construction fields. 


  • Rated voltage: up to 24kV
  • Rated short-circuit breaking current: from 20kA up to 31.5 kA
  • Rated current: 630A
  • Basic functional module units with uniform dimensions
  • Internal arc classified 20kA/1s
  • Less than 0.1% annual leakage rate
  • Each unit can extend to the left or right freely
  • One gas tank can accommodate up to 5 modules combined freely
  • Low maintenance
  • Tested in accordance with the IEC international standards

Small and Compact

SecoRMU uses a vacuum circuit breaker and adopts SF6 gas as the insulated medium in the gas tank. SF6 has excellent dielectric insulating performance. Its insulating strength is approximately 2-3 times the strenght of air in an uniform electric field. The excellent insulating performance of SF6 gas Maintaince free helps SecoRMU to realize its small and compact structure, as well as safety and reliability.

Safe and Reliable

Both the gas tank and the cable compartment are internal arc classified (20kA/1s), in order to ensure maximum personal safety. Three position switch for natural interlocking.

Fully Modular Design/Extendable

The basic functional module units have uniform dimensions: 350×800×1380mm (width ×depth× height). Convenient for system design, flexible replacement and upgrading. Each unit can extend to the left or right freely. Specially designed busbar connectors make the combination and extension of SecoRMU switchgear simple, safe and reliable. The big cable compartment also ensures a convenient cable installation and connection.

Environment Independent/ Very Low Maintenance

SecoRMU is environment independent because its primary conductive system is fully sealed in the SF6 gas tank and will not be influenced by the outside world. Its sealing is systematically checked by automatic helium leakage detection process at the factory, ensuring less than 0.1% annual leakage rate. The gas tank passed water immersed testing, reaching IP67 protection grade. Besides, SecoRMU realizes no clearance splicing for installing an extension, independent of the impact of dew, dust, salt fog, small animals, chemical substances, etc. Therefore, SecoRMU is free of maintenance.