Rated 12kV with 11kV as the working voltage in many markets. The busbar is 630A and every way uses a three-position load break switch rated 20kA/3s short-circuit. The complete ring main unit switchgear assembly is type-tested to IEC 62271-200 and ships IP54 for outdoor duty. We also build the SF6-free solid insulated ring main unit if your tender requires it.
Yes, for most utility projects outside the EU. SF6 remains the default dielectric for a gas insulated substation and for the gis substation class of switchgear in Africa, the Middle East, and Southeast Asia. Inside the EU, F-gas rules phase down new SF6-filled equipment, so an SF6 insulated ring main unit there needs registry checks on gas quantity. Sealed-for-life tanks keep leak rates small, which is why SF6 still dominates.
A sealed-for-life SF6 gas insulated switchgear tank needs no internal maintenance for 30 years. The SF6 gas insulated RMU tank is welded shut at the factory, filled once, and never opened in the field. Only external items need checks: cable terminations, enclosure seals, and the motor mechanism, usually every 5 to 10 years. That long interval is the main reason utilities stay with this SF6 gas insulated switchgear design.
Yes. The sealed SF6 tank is an outdoor ring main unit built for pad-mounting, IP54 rated, dust-tight and splash-proof. As an SF6 insulated ring main unit, everything live sits inside the sealed tank, so rain, dust, and coastal humidity stay out. Motor operation is available, which makes it a SCADA-ready remote switching point. No building and no fencing are required, which is what most ring main unit switchgear buyers want.
A gas insulated substation is the larger integrated form: full circuit breakers, disconnectors, and busbars in SF6 enclosures, usually above 33kV. The RMU, which you may see written as gas insulated rmu, is the compact member of the same gis switchgear family for 12kV distribution. Both use SF6 dielectric; the gis substation feeds a region, the RMU switches a ring at the transformer pad.
SF6 gas carries three to four times the dielectric strength of air, so phase spacing shrinks and the cabinet stays compact. That is the whole reason gas insulated switchgear became standard for outdoor distribution, and why our SF6 gas insulated RMU is built as an SF6 gas insulated switchgear unit rather than an air-insulated one. The gas also quenches arcs fast, which makes the three-position switch reliable at 20kA/3s.
It is a compact member of the gis switchgear family, and most buyers call it a gas insulated rmu. Inside a sealed stainless-steel tank, SF6 gas surrounds three-position load break switches with closed, open, and earthed positions. The SF6 gas insulated RMU works at 12kV (11kV), rated 630A busbar with 20kA/3s short-circuit. It does the same job as a ring main unit or ring main unit switchgear but in a smaller footprint.
