| Brand | ROCKWILL |
| Series | RMR,RGIS,REC |
A 24kV class ring main unit with no sulfur hexafluoride — insulated by pure/dry air or solid dielectric, interrupted by vacuum, and engineered as a direct, low-environmental-impact replacement for urban secondary distribution.
24kV is the standard urban medium-voltage ring voltage in many networks — and the voltage where the largest installed base of SF6 ring main units is reaching replacement age.
A 24kV SF6 free RMU lets you renew those rings without reintroducing SF6. It keeps the same 24kV rated insulation level, the same ring-and-transformer feeder logic, and a compatible footprint — while switching to a zero-GWP SF6 alternative RMU insulated by pure air, dry air or solid dielectric. No greenhouse gas means no leakage reporting, no F-gas exposure and a cleaner net-zero tender story.
Purpose-built for 24kV secondary rings feeding distribution transformers in cities and industrial parks.
Matches conventional RMU footprints and cable arrangements, so retrofit projects stay simple.
Sealed vacuum interrupters — independent of the insulation medium, proven over decades.
24kV stresses the dielectric more than 12kV, which is why the insulation design matters. Our air/solid systems are dimensioned and type-tested for the 24kV class.
Choose a pure air insulated RMU for the lowest environmental footprint and breathable, safe on-site conditions; choose dry-air or solid insulation where footprint, pollution or humidity demand a more compact construction. Every unit pairs the insulation system with a sealed vacuum interrupter, giving you the SF6-free RMU performance that 24kV rings require — without the gas.
Representative values; the certified datasheet is prepared on request — contact us.
| Parameter | Typical value |
|---|---|
| Rated voltage | 24kV |
| Power frequency withstand | 50kV (1 min) |
| Lightning impulse withstand | 125kV |
| Rated frequency | 50 / 60 Hz |
| Busbar rated current | 630A (up to 1250A on request) |
| Rated short-time withstand | 20kA / 3s (25kA on request) |
| Insulation medium | Pure/dry air or solid — SF6-free, GWP 0 |
| Breaking device | Sealed vacuum interrupter |
| Configuration | Ring incomers + transformer feeder (switch-fuse / VCB) |
| Standard | IEC 62271-1, -102 / -103 |
Send us your ring layout, fault level and cable schedule. We will return a configuration, certified datasheet and export quote within one working day.
We are the factory, not a trading company. As an experienced SF6-free RMU manufacturer, we own design, fabrication, vacuum-interrupter assembly, type testing and export packing under one roof.
Distributors, EPC contractors and switchgear brands work with us under OEM/ODM: your nameplate, your manuals, your packaging, engineered from your single-line diagram. Alongside our RMUs we supply dry air switchgear for industrial incomers and feeder schemes — so you can source the whole SF6-free secondary network from one certified partner.
Yes, Rockwill provides comprehensive OEM/ODM programs for the RAR series SF6 Free Switchgear. However, we are selective in our partnerships; we specifically seek technically capable manufacturers and local partners who possess strong engineering backgrounds and local service capabilities. Our goal is to collaborate with entities that can not only distribute but also technically support our advanced pure-air insulation technology in their regions.
Yes. It is rated to the same 24kV class with matching withstand levels and feeder logic, and is designed around conventional footprints so retrofit work stays minimal.
When the system is dimensioned and type-tested to the 24kV withstand levels, dry air or solid insulation provides reliable phase-to-earth insulation — combined with vacuum interruption.
Zero GWP insulation means no SF6 leakage to report, no F-gas compliance burden and no gas-recovery cost at end of life.
Yes. We manufacture 24kV SF6-free RMUs for distributors and EPCs under OEM/ODM with your nameplate and documentation.
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