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Ring Main Units (RMU)
12 Series · 13 Models
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Ring Main Units (RMU) Overview
Ring main units (RMUs) are compact, sealed switchgear that feed and protect medium-voltage ring networks. QDTB RMUs integrate load break switches, circuit breakers, and earth switches in gas-insulated (SF6) enclosures rated 12/24 kV up to 630 A per IEC 62271-200. The sealed-for-life design needs essentially no maintenance and occupies roughly one-third the footprint of conventional air-insulated gear, while modular construction allows additional compartments to be added as the network grows.
Available Series
SRM12 Series
The SRM12 series ring main units with integrated FTU combine primary switching equipment with secondary automation. Factory tested with primary and secondary systems merged into one device for fast deployment in distribution automation projects.
XGN15 Series
The XGN15 series ring main units with integrated FTU combine switching equipment with feeder automation terminals. Primary and secondary systems merged into one factory-tested device for rapid deployment in smart grid distribution networks.
FLN36 Series
The FLN36 series ring main units with integrated FTU represent the convergence of primary equipment and secondary automation. Factory tested with all protection and monitoring functions pre-configured for fast deployment in distribution networks.
Pad-Mounted Ring Main Units Series
American style pad-mounted ring main units (pad-mounted switchgear / vault switchgear) provide dead-front, tamper-resistant switching and protection for underground distribution loops, built to ANSI/IEEE C57.12.28 construction with SF6 or vacuum interruption. Rated 12–38 kV, 600A continuous with loop-feed and tap configurations, suitable for public pad-mount and vault installations.
SM6 Series
The SM6 series SF6 ring main units feature sealed SF6 gas insulation tanks for maintenance-free operation in urban power distribution networks. Modular design with load break switch and fuse or vacuum circuit breaker protection options.
RM6 Series
The RM6 series SF6 gas-insulated ring main units provide reliable medium voltage switching for distribution networks. All-in-one sealed SF6 tank design ensures long-term maintenance-free performance with load break switch and fuse combination protection.
SafeRing Series
The SafeRing series represents ABB-compatible SF6 gas-insulated compact ring main units with advanced safety features. Fully sealed design with SF6 insulation provides excellent performance in harsh environments while ensuring operator safety.
8DJH Series
The 8DJH series SF6 gas-insulated switchgear provides reliable medium voltage switching for urban distribution networks. Features sealed SF6 tank design with load break switch and vacuum circuit breaker protection modules for maintenance-free operation.
GXS Series
The GXS series solid-insulated ring main units represent the next generation of SF6-free, environmentally friendly switchgear. Features epoxy-encapsulated live parts eliminating SF6 gas, ideal for eco-buildings and environmentally sensitive applications.
XGN Series
The XGN series solid-insulated ring main units provide SF6-free, environmentally friendly medium voltage switching. Features epoxy encapsulation of all live parts, eliminating greenhouse gas emissions while maintaining reliable switching performance.
Dry Air Insulated Ring Main Units Series
Dry air insulated ring main units (eco RMU) use clean dry air or nitrogen insulation instead of SF6, eliminating fluorinated greenhouse gas while providing compact ring-main switching and protection. Rated 12–24 kV, 630A, for green buildings, underground networks and SF6-free projects.
VCB Ring Main Units Series
VCB ring main units use vacuum circuit breakers for the transformer and feeder protection ways, providing full breaking capacity instead of load-break switching alone. Rated 12–24 kV, 630–1250 A with circuit-breaker protection modules, for distribution networks requiring fault interruption at each way.
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| Base price (interpolation) | $2,350 |
| × Product factor | ×1.0000 |
| × Country factor | ×1.0000 |
| × Copper-linked factor | ×1.0000 |
| + Options / accessories | $0 |
Complete equipment — no winding copper linkage
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Application Scenarios
Urban Ring Networks
Primary switchgear with automatic fault isolation.
Wind Power
MV switchgear for wind farm collection.
Solar Plants
MV distribution for PV plants.
Commercial
Compact RMU for developments.
Industrial
Factory substation switchgear.
Infrastructure
Railway and airport distribution.
Technical Advantages
Gas-Insulated
SF6/clean air, maintenance-free 30+ years.
Modular
2-6 compartments configurable.
Protection
Complete switching in one sealed unit.
Smart Grid
Motorized operation and remote monitoring.
FAQ - Ring Main Units (RMU)
What is the difference between SF6 and air-insulated RMUs?
How many feeders can an RMU support?
What is the difference between a load break switch and a circuit breaker?
Are RMUs suitable for renewable energy projects?
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