Ring Main Unit(RMU)

Modernise your grid with the smart RMU

A ring main unit (RMU) is a factory assembled, metal enclosed set of switchgear used at the load connection points of a ring-type distribution network. It includes in one unit two switches that connect both sides of the load to the main conductors and a fusible switch or circuit breaker that tee-off to feed a distribution transformer medium voltage to low voltage (MV to LV).The smart ring main unit (RMU) is an innovative solution that makes it easier for you to answer the evolving challenges of electrical distribution. As an all-in-one solution, the smart RMU is easy to purchase, install and maintain, helping to reduce operational costs. Its robust design fits even the harshest environments.


Gas-Insulated Ring Main Unit up to 24 kV.Fully SF6-insulated RMU switchboard for secondary distribution networks, available in compact or extensible installation footprints to best suit to your application

Features :

Gas-Insulated Switchgear

The FBX is a fully SF6-insulated switchboard for secondary distribution networks.

In its compact version (FBX-C), it acts as a Ring Main Unit, includes up to five different functions into a single tank and can be easily integrated into a substation or wind tower mast.

In its extensible version (FBX-E), it becomes a fully modular switchboard suitable for industrial applications.

Both innovative and safe, it is insensible to environment, virtually maintenance free and very easy to install and operate.

  • SF6-insulated switchgear for secondary distribution network
  • SF6 switch-disconnector
  • Protection through fuse combination or vacuum circuit-breaker 
  • Two versions : FBX-C (Compact), FBX-E (Extensible)
  • Compliant with IEC 62271-200
  • Rated Voltage: 12 / 17.5 / 24 kV
  • Bus-bar Rated Current: 630 A
  • Feeder Rated Current: 630 A
  • Rated Short Time Withstand Current : up to 21 kA 3s (up to 25 kA 1s for 12 kV)
  • Internal Arc Containment : up to 25 kA 1s
  • Dimensions W x H x D in mm: 2 switch-disconnectors + circuit-breaker or fuse protection functions:
    • 1000 x 1380 x 750
  • Option : can be remotely controlled and monitored through a RCX-ITI remote terminal

Contractual warranty

Period : 18 months

Benefits :
  • Simple Installation & Operation
    • Very compact with small dimensions
    • Easy installation and extension with plug-in connection
    • Very clear user panel with position indicators
    • Large front cable compartment for easy access to bushings
  • Improved continuity of service
    • Continuity of service LSC2A
    • Can be remotely controlled and monitored
    • Flood proof
    • Independent from environmental conditions even in highly polluted areas
    • Maintenance free
  • Improved personnel safety
    • Internal Arc Withstand
    • Integrated interlocks for fool-proof protection
    • Padlocking available for all operations
  • Environmentally friendly and fully recyclable
Applications :
  • Transformer protection by fuse (T1 function)
  • Transformer protection by vacuum circuit-breaker (T2 function)
  • Protection by O-C-O vacuum circuit-breaker (CB or CBb function)
  • Switchboard to fit many secondary distribution applications such as:
    public distribution, industry, infrastructure or renewables