Product category
Ring Main Units for Secondary Distribution
Ring Main Units (RMUs) combine medium-voltage switching and protection functions in compact equipment arrangements for secondary distribution. They support network sectionalising and the connection of distribution feeders or transformers, with specific operation determined by the switchgear configuration.
Equipment options
Compare at a glance
Key catalogue values only. The full approved rating matrix lives on each product page.
| Characteristic | Indoor SF6 RMUCSG I | Indoor/Outdoor SF6 RMUCSG IK | Outdoor SF6 RMUCSG O |
|---|---|---|---|
| Rated voltage | 12 | 24 kV | 12 | 17.5 kV | 12 | 17.5 kV |
| Rated current | 630 | 630 A | 630 | 630 A | 630 | 630 A |
| Rated short-time current | 21 for 3 s | 21 for 3 s kArms | 21 (3 s) | 21 (3 s) kA rms | 21 (3 s) | 21 (3 s) kA rms |
| Protection degree | Mechanism IP2X · Cable compartment IP3X · Tank IP67 · Canopy/enclosure IP54 | RMU IP54 · Tank IP67 | RMU IP54 · Tank IP67 |
01
Select the operating environment
Indoor RMU — for qualified indoor installations. Indoor/outdoor RMU — for applications within the approved installation envelope. Outdoor RMU — for outdoor distribution locations. 33 kV RMU — a separate announced product category requiring its own approved specification.
02
How RMUs fit the network
The number and type of load-break switches, circuit-breaker functions, protection, metering, earthing and remote-control interfaces come from the network's single-line diagram and utility specification.
03
Smart distribution options
Where a product version supports motorisation and suitable communications, an RMU may be integrated into a broader distribution automation scheme. Confirm exact options, control architecture and interoperability.
04
Engineering checklist
- Installation environment
- Network topology
- Voltage class
- Rated current
- Short-circuit duty
- Functional modules
- Protection
- Cable terminations
- Automation requirements
- Utility specification
05
Learning module
- 01What is an RMU?
- 02What is the difference between LBS and circuit breaker functions?
- 03How does ring network sectionalising work?
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