Medium voltage · Secondary distribution
Secondary distribution, sealed for life, ready for the grid that runs itself.
Our RMU family covers three insulation technologies: air-insulated, air-insulated with SF6 switches (AIS), and fully gas-insulated (GIS). Sealed for the asset's service life, smart-ready via Modbus or IEC 61850, and engineered for the secondary distribution networks that Vision 2030's smart grid programme is built on.
- Voltage
- 12 / 17.5 / 24 kV
- Continuous current
- 630 A
- Short-time current
- Up to 25 kArms · 4 s
- Endurance class
- E3 · M1
The range
Three insulation technologies. One sealed-for-life standard.
From traditional air-insulated to fully gas-insulated, each technology serves a different deployment context. All three share the same E3/M1 endurance classification and the same smart-grid readiness.
Up to 24 kV · Air-insulated01 / 3Air ring main unit
Air-insulated RMU type-tested per the latest IEC 62271 series. Encapsulated extinguishing device, current interruption without visible arc. The reference choice for traditional secondary distribution where air insulation is specified.
12 / 17.5 / 24 kV · 630 A · 25 kA / 4 s · E3 · M1
Up to 24 kV · SF6 switches02 / 3Air-insulated SF6 ring main unit
Air-insulated busbar with SF6 gas-insulated switch compartments. Modular four-compartment construction: cable, busbar, mechanism, and low-voltage compartments, each metal-separated for safety and serviceability.
12 / 24 kV · 630 A · 25 kArms · 63 kApeak
Up to 24 kV · Fully gas insulated03 / 3Fully gas-insulated SF6 ring main unit
Maintenance-free
Fully gas-insulated, sealed-for-life RMU with a four-element construction: electrical switching, drive mechanism, fuse, and cable. Compact and maintenance-free for transmission, distribution, and solar collection networks.
12 / 24 kV · 630 A · 25 kArms · Sealed for life
Side-by-side specifications
Full technical comparison across the RMU range.
| Specification | Air RMU | AIS RMU | GIS RMU |
|---|---|---|---|
| Insulation | Air | Air + SF6 switches | Fully SF6, sealed |
| Rated voltage | 12 / 17.5 / 24 kV | 12 / 24 kV | 12 / 24 kV |
| Frequency withstand, 1 min | 28 / 38 / 50 kVrms | 50 kVrms | 50 kVrms |
| Impulse withstand | 75 / 95 / 125 kVpeak | 125 kVpeak | 125 kVpeak |
| Rated frequency | 50 / 60 Hz | 50 / 60 Hz | 50 Hz |
| Rated current | 630 A | 630 A | 630 A |
| Short-time withstand | Up to 25 kA / 4 s | Up to 25 kArms | Up to 25 kArms |
| Peak withstand | 63 kA | 63 kApeak | 63 kApeak |
| Electrical endurance | E3 | E3 | E3 |
| Mechanical endurance | M1 | M1 | M1 |
| Maintenance | Periodic | Reduced | Maintenance-free |
| SCADA-ready | Supported | Supported | Supported |
| Footprint | Standard | Compact | Most compact |
| Indoor / outdoor | Indoor / outdoor | Indoor / outdoor | Indoor / outdoor |
Air RMU
- Insulation
- Air
- Rated voltage
- 12 / 17.5 / 24 kV
- Frequency withstand, 1 min
- 28 / 38 / 50 kVrms
- Impulse withstand
- 75 / 95 / 125 kVpeak
- Rated frequency
- 50 / 60 Hz
- Rated current
- 630 A
- Short-time withstand
- Up to 25 kA / 4 s
- Peak withstand
- 63 kA
- Electrical endurance
- E3
- Mechanical endurance
- M1
- Maintenance
- Periodic
- SCADA-ready
- Supported
- Footprint
- Standard
- Indoor / outdoor
- Indoor / outdoor
AIS RMU
- Insulation
- Air + SF6 switches
- Rated voltage
- 12 / 24 kV
- Frequency withstand, 1 min
- 50 kVrms
- Impulse withstand
- 125 kVpeak
- Rated frequency
- 50 / 60 Hz
- Rated current
- 630 A
- Short-time withstand
- Up to 25 kArms
- Peak withstand
- 63 kApeak
- Electrical endurance
- E3
- Mechanical endurance
- M1
- Maintenance
- Reduced
- SCADA-ready
- Supported
- Footprint
- Compact
- Indoor / outdoor
- Indoor / outdoor
GIS RMU
- Insulation
- Fully SF6, sealed
- Rated voltage
- 12 / 24 kV
- Frequency withstand, 1 min
- 50 kVrms
- Impulse withstand
- 125 kVpeak
- Rated frequency
- 50 Hz
- Rated current
- 630 A
- Short-time withstand
- Up to 25 kArms
- Peak withstand
- 63 kApeak
- Electrical endurance
- E3
- Mechanical endurance
- M1
- Maintenance
- Maintenance-free
- SCADA-ready
- Supported
- Footprint
- Most compact
- Indoor / outdoor
- Indoor / outdoor
Where it's deployed
The secondary distribution layer of every modern Saudi network.
From kiosk substations to solar collection plants, RMUs sit at the layer where the medium-voltage distribution grid meets the load.
- 01
Municipal distribution networks
The backbone of urban and suburban distribution. RMUs in kiosk substations feed residential blocks, commercial zones, and public infrastructure across Saudi cities.
- 02
Housing and real-estate developments
Vision 2030 housing initiatives require thousands of distribution kiosks. Compact GIS RMUs are specified where land area is constrained or aesthetics matter.
- 03
Renewable energy plants
Solar PV collection networks. Sealed-for-life GIS RMUs at maintenance intervals matched to the inverter station service life reduce lifetime cost across distributed plants.
- 04
Industrial facilities
Secondary distribution within factory campuses, process plants, and logistics hubs.
- 05
Commercial buildings
Service entrance and distribution for shopping centres, office complexes, and mixed-use developments.
- 06
Smart grid programmes
SCADA-integrated RMUs with remote control and protection coordination. Compatible with the IEC 61850 substation automation standard.
Typical kiosk substation arrangement: TEPCO RMU bay feeding a distribution transformer, with LV outgoing feeders on a BlokSeT panel.
Engineered to standard
Type-tested. Sealed for life. Smart-ready.
The RMU family is designed and type-tested against the IEC switchgear series, with the certifications a Saudi industrial buyer expects.
IEC standards compliance
- IEC 62271-1Common specifications for HV switchgear and controlgear.
- IEC 62271-100High-voltage AC circuit-breakers.
- IEC 62271-102HV AC disconnectors and earthing switches.
- IEC 62271-103Switches above 1 kV up to 52 kV.
- IEC 62271-105AC switch-fuse combinations.
- IEC 62271-200AC metal-enclosed switchgear above 1 kV up to 52 kV.
- IEC 60265High-voltage switches.
- IEC 60298AC metal-enclosed switchgear, legacy AIS reference.
Management systems and protocols
- ISO 9001 : 2015
- ISO 14001 : 2015
- ISO 45001 : 2018
- IEC 61850 · SCADA
Documentation
Everything your engineering team needs to specify, install, and commission.
Datasheets, dimensional drawings, type-test certificates, and installation manuals, released on engagement to the named project team.
Family datasheet
PDF · ~6 MB
All three RMU variants, full specifications, and single-line diagrams.
Request copy
Dimensional drawings
PDF + DWG · ~9 MB
CAD-ready drawings including kiosk substation integration.
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Type-test certificates
PDF · ~5 MB
Independent IEC type-test certificates from accredited international laboratories.
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Installation manual
PDF · ~3 MB
Installation procedures, commissioning checklists, and SF6 handling protocols.
Request copy
RMU documentation is released under non-disclosure to qualified buyers. Send your project reference and we will return the bundle within one working day.
Often deployed together
Related products in the TEPCO portfolio.
The families most often specified alongside ring main units on Saudi distribution projects.
Integrated solution
Package substations
Integrate RMUs with the transformer and LV panel in a factory-assembled compact substation.
View substations
Primary distribution
Medium voltage switchgear
RMUs sit downstream of primary MV switchgear in larger distribution hierarchies.
View MV switchgear
Digital
Smart grid and automation
Add IEC 61850 protection and SCADA to any RMU installation for full network visibility.
View smart grid
Ready to specify ring main units?
Send us your network configuration or technical requirement. Our Madinah engineering team will respond within 24 hours.