Solid Insulated ring main unit is a RMU which uses solid insulated materials as main insulating medium.

Connect the vacuum arc-extinguishing chamber with its electric conduction, disconnector, earthing switches, main bus, branch main bus and other dominant electric circuits.

After single or combination, cover it with insulated solid medium as one or multiple functional, recombinational or re-extensible models with full insulation or full airtightness. The touchable model surface is coated with a conductive or semi-conductive shielding layer which can be directly and solidly grounded to the ring main unit.

FSRMU Series Solid Insulated Switchgear is independently developed by Farady Electric.

Featuring modular design, this switchgear is small in size, maintenance-free, easy to operate, safe and reliable and environmental-friendly and can meet the demand of different power supply plans to the maximum degree. The switchgear can be installed indoor compact transformer or directly installed outdoor in a box.

Service environment

a) Air temperature:Maximum temperature: +40℃; Minimum temperature:-20℃

b) Humidity:Monthly average humidity 95%; Daily average humidity 90% .

c) Altitude above sea level:Maximum installation altitude: 2000m

d) Ambient air not apparently polluted by corrosive and flammable gas, vapor etc.

e) No frequent violent shake

Application standard

l IEC62271-100: Part 100: Alternating-current circuit-breakers

l IEC 62271200: Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV

l IEC 62271-102 : Part 102: Alternating current disconnectors and earthing switches.

l IEC 62271103 :Part 103: Switches for rated voltages above 1 kV up to and including 52 kV

l IEC 62271105: Part 105 – Alternating Current Switch-Fuse Combinations


  1. Eliminate the use of SF6 gas, thus reducing the emission of greenhouse gases and leakage of hazardous gases generated by SF6 gas decomposition and realizing truly safe, enthronement-friendly, innocuous and harmless application.
  2. Avoid pressure gas tank design, eliminating the possibility of hazardous accidents caused by degrading insulating ability due to SF6 gas leakage.
  3. Air insulation mode is adopted which will not give rise to air leakage and insulating ability degradation.
  4. Live parts are sealed with epoxy to form a fully insulated and sealed structure of high IP grade.
  5. Simple and reliable operating mechanism greatly improves the security.
  6. Intensified phase-to-phase isolation and split-phase insulation design may prevent phase-to-phase faults.
  7. Upper isolation design can realize ground closing and opening through the arc extinction chamber, which is in line with the grid safety design.
  8. The modular structure contributes to loop expansion, unit exchange and plan alteration.
  9. Three phases at the isolation switched fracture are independent and clear and the contact sites are directly visible and LED lighting is provided.
  10. Complete mechanical interlock function, fully meeting interlocking protection requirements. Ensure operational safety.
  11. Coated with semi-conductive shielding layer and reliably grounded, the module is touchable with higher security.
  12. The bus cable adopts special flexible shielded cable, avoiding stress generated due to improper installation, thus improving the operational reliability.
  13. The cabinet structure is reasonably designed and a bushing transformer is used. This significantly lower the level of difficulty for the installation of dual-cable inlet and outlet.

Technical Data

Product Structure

Main Structure
Vacuum Interrupter no SF6 Gas
**Main Connection Embedded in solid insulation **