Ring Main Unit

Our new RMU

The RMU switchboards of the Bonomi Group, insulated in gas, allow the connection, power supply and protection of transformers for open or radial ring networks. Transformer protection can be achieved:
  • with a combination of fuses and switches for transformers up to 2,000 kVA.
  • via a switch with a protection relay for transformers up to 8,000 kVA.
Thanks to line protection with 630A circuit breakers, network switching via disconnectors and integrated remote power control devices, our RMUs allow for various connections.



  • Generation: wind energy, solar energy
  • Distribution: compact substations, RMU network protection
  • Private measurement
  • Large transformer substation
  • Separate MV substation


  • Tunnels, airports, seaports, metro stations, urban railways


  • Commercial buildings: hospitals, shopping malls, hotels, office buildings, data centers, schools
  • Residential buildings: houses, apartments


  • Acqua e acque di scarto, estrazione mineraria, minerali, automotive
  • Acciaierie, cementifici industrie del petrolio

Our solutions Smart Grid