Dis Sub-12 SF6 Gas-Insulated RMU (12kV)
RAYDAFON Dis Sub-12 SF6 Gas-Insulated RMU delivers 12kV distribution switching with SF6 gas sealed in a stainless steel tank at 0.04 MPa — annual leakage ≤0.01%, IP67-rated. Load switch, vacuum circuit breaker, and electrified busbar are all encapsulated for 30-year maintenance-free operation. Supports up to 5 modules per tank with busbar extension. Suitable for 12kV ring network or terminal power supply systems in flood-prone, coastal, and contaminated environments.
What Is an SF6 Gas-Insulated RMU?
An SF6 gas-insulated RMU (Ring Main Unit) uses sulfur hexafluoride as the primary insulating and breaking medium. The RAYDAFON Dis Sub-12 seals the load switch, vacuum circuit breaker, and electrified busbar inside a hermetically welded stainless steel tank filled with SF6 at 0.04 MPa. SF6 has about three times the dielectric strength of air, allowing a much more compact tank and higher ratings in the same footprint. The sealed construction delivers IP67 protection — blocking moisture, dust, salt spray, and flood water — making it ideal for outdoor installations, underground vaults, and coastal substations.
SF6 Insulated · 0.04 MPa 12kV / 630A / 20kA IP67 Sealed Tank 30-Year Maintenance-Free
Inside the SF6 Tank — Why Gas Insulation Wins
SF6 Gas Performance at a Glance
Leakage Rate Below Industry Standard
0.01% max per year
Sealed Tight — Verified by Laser-Welded Tank Design
The Dis Sub-12 uses a laser-welded stainless steel tank that is pressure-tested before assembly. The tank is equipped with a pressure gauge and gas-filling port for periodic verification, and the annual SF6 leakage ratio is capped at 0.01% — well below the IEC 62271-1 standard threshold.
Actual Leakage≤ 0.01% / year
IEC Standard Limit≤ 0.5% / year
Three-Layer Sealed Protection
Why the Sealed Tank Outperforms Air-Insulated Designs
LAYER 01 — OUTER ENCLOSURE IP67 Stainless Steel Cabinet Blocks flood water, salt spray, dust, and industrial contamination
LAYER 02 — INSULATION MEDIUM SF6 Gas at 0.04 MPa 3× dielectric strength of air · arc-quenching medium · no oxidation
LAYER 03 — PRIMARY CIRCUIT Fully Encapsulated Switching Core Vacuum interrupter + three-station switch + busbar
Why Choose SF6 Gas-Insulated Over Air-Insulated?
- Compact footprint — SF6's high dielectric strength allows a much smaller gas tank and enclosure. Same 12kV rating in less space.
- Harsh environment ready — IP67 sealed tank resists flood water, salt spray, dust storms, and chemical atmospheres. No periodic cleaning required.
- Zero exposure — the primary circuit is completely isolated from ambient air. No condensation, no oxidation, no external contamination.
- Longer service life — sealed switching core operates for 30 years without maintenance, ideal for unmanned remote sites.
- Coordinated protection — mechanical interlocks and simulation identification on the cabinet panel prevent misoperation.
- Full remote monitoring support — compatible with RAYDAFON Remote-9001 for cloud-edge SCADA integration. See remote monitoring →
Product Features
- Maintenance-Free 30 Years — SF6 gas, movable and fixed contacts, arc-extinguishing chamber, and busbar are sealed in one gas box. No periodic gas topping-up, cleaning, or contact inspection required.
- Reliable Mechanical Interlock — Multiple mechanical interlocks and simulation identification on the cabinet panel ensure safe operation and prevent misoperation between load switch, breaker, and grounding switch.
- Full-Sealed and Insulated In/Out Cables — Full-sealed insulated cable connectors matched to user requirements. Electrified display functions show each circuit status precisely.
- Modularized and Expansible — One gas tank holds up to 5 modules. Additional modules connect through busbar extension for larger substation configurations.
- Multiple Connection Schemes — Load switch, load switch + fuse, or vacuum circuit breaker combinations for various incoming and feeder line circuits.
- Visible Open Contacts — Observation window on the panel shows the open contacts of the load switch and the position of the grounding switch.
- Electric Operation and FTU-Ready — Special voltage transformers collect power for the operating mechanism and FTU. Dedicated battery and charging modules ensure continuous power supply.
Six Configurable Module Types
CCircuit Breaker
FLoad Switch + Fuse
VVacuum CB
PTVoltage Transformer
MMetering
DBus-Tie
Key Performance at a Glance
Dis Sub-12 SF6 — Core Parameters
12kVRated Voltage
630ARated Current (Main)
20kAShort-Time Withstand / 4s
50kAPeak Withstand Current
42kVPower Freq. Withstand (Ph-G)
75kVLightning Impulse (Ph-G)
0.04MPaSF6 Rated Pressure (20°C)
≤0.01%SF6 Annual Leakage Ratio
Full Technical Parameter Table
| Item | Unit | Parameter |
|---|---|---|
| Rated Voltage | kV | 12 |
| Rated Current (Main) | A | 630 |
| Rated Frequency | Hz | 50 (60 optional) |
| Power Freq. Withstand — Phase-Earth / Phase-Phase / Break | kV | 42 / 48 |
| Lightning Impulse — Phase-Earth / Phase-Phase / Break | kV | 75 / 85 |
| Short-Time Withstand Current — Main & Ground Circuit | kA | 20 |
| Peak Withstand Current | kA | 50 |
| Short-Time Withstand Duration | s | 4 |
| Rated Thermal Stability Current | kA | 20 |
| Rated Dynamic Current | kA | 50 |
| Rated Current — Fuse Circuit (Max) | A | 125 |
| Rated Transfer Current | A | 1,700 |
| Breaking Capacity — Vacuum Circuit Breaker | kA | 20 |
| Mechanical Life — Load Switch | ops | 10,000 |
| Mechanical Life — Vacuum Circuit Breaker | ops | 10,000 |
| Mechanical Life — Grounding Switch | ops | 5,000 |
| SF6 Rated Pressure (20°C) | MPa | 0.04 |
| SF6 Annual Leakage Ratio | % | ≤ 0.01 |
| Operating Power Supply Voltage | V | DC 24 / 48; AC 220 |
Industry Applications
- Outdoor Distribution Substations — The IP67 sealed tank resists rain, dust, and temperature extremes. The Dis Sub-12 is ideal for pad-mounted, pole-mounted, and outdoor kiosk substations.
- Underground Vaults & Basements — Sealed construction prevents moisture ingress in high-humidity underground environments.
- Coastal & Marine Installations — Salt spray resistance extends switchgear life in ports, offshore platforms, and coastal industrial parks.
- Ring Network Distribution — The 12kV rating matches urban and industrial ring main configurations. See full RMU range →
- Industrial Plants & Petrochemical Sites — Sealed tank blocks chemical vapors and contaminants that would degrade air-insulated switchgear.
- Rail & Metro Substations — Compact dimensions suit underground stations and traction power rooms.
- Renewable Energy Collector Systems — Wind and solar farm collector substations with sealed switchgear protection. See ESS range →
- Prefabricated Substation Integration — Designed to fit into RAYDAFON YBM prefabricated substations. See prefabricated substations →
SF6 vs. SF6-Free vs. Air-Insulated: Which RMU Fits Your Project?
- SF6 Gas-Insulated (this product) — Most compact footprint, IP67 sealed tank, best for harsh environments (coastal, underground, flood-prone) and highest reliability. Environmental regulatory risk in some regions.
- SF6-Free Gas-Insulated — Uses dry air + eco-gas instead of SF6. Same IP67 sealed construction, GWP ≈ 1, compliant with future regulations. Ideal for ESG-sensitive projects. See SF6-free RMU →
- Air-Insulated — Simple, maintenance-friendly, fully recyclable. Lower cost, but larger footprint (no sealed gas tank). Best for indoor box substations where space is not critical. See air-insulated RMU →
Why Choose RAYDAFON as Your SF6 Gas-Insulated RMU Manufacturer
- 20+ Years of Power Equipment Experience — RAYDAFON Technology Group has served the electrical equipment industry for over two decades, with products deployed across 40+ export countries.
- Integrated Switchgear & Substation Manufacturing — We manufacture RMUs, switchgear, prefabricated substations, and monitoring units under one roof. The Dis Sub-12 integrates directly with our YBM prefabricated substations for turnkey projects.
- 25+ Patents — Proprietary designs across sealed tank geometry, SF6 pressure management, three-station switch mechanism, and modular expansion architecture.
- ISO/IEC Certified Manufacturing — All products manufactured under ISO/IEC quality management systems and tested to IEC 62271-200 standards, with full third-party type-test reports available on request.
- SF6 Handling & Recovery Support — For markets with SF6 regulations, RAYDAFON provides gas-filling documentation, leakage-test certificates, and end-of-life recovery guidance.
- 24-Hour Engineering Response — Dedicated engineering team provides technical selection support and after-sales service within 24 hours.
Frequently Asked Questions
What is an SF6 gas-insulated RMU?
An SF6 gas-insulated RMU (Ring Main Unit) is a medium-voltage switchgear that uses sulfur hexafluoride gas as the primary insulating and breaking medium. The Dis Sub-12 places the load switch, vacuum circuit breaker, and electrified busbar inside a hermetically sealed stainless steel tank filled with SF6 gas at 0.04 MPa. SF6's high dielectric strength (about 3× that of air) allows the gas tank to be far more compact than air-insulated alternatives, while the sealed construction blocks moisture, dust, and flood water.
Why use SF6 instead of air insulation?
SF6 gas has three times the dielectric strength of air, which allows a much more compact gas tank and higher voltage ratings in the same footprint. The sealed tank also fully isolates the primary circuit from the external environment — providing IP67 protection that resists flood water, salt spray, dust, and industrial contamination. This makes SF6 gas-insulated RMUs suitable for harsh outdoor installations, underground vaults, and coastal substations where air-insulated switchgear would require periodic cleaning and inspection.
What is the SF6 leakage rate?
The Dis Sub-12 uses a stainless steel tank that is laser-welded and pressure-tested before assembly, with a rated pressure of 0.04 MPa at 20°C and an annual leakage ratio of ≤0.01%. This is significantly below the IEC 62271-1 standard threshold and comparable to premium imported SF6 switchgear. The tank is also equipped with a pressure gauge and gas-filling port for periodic verification.
What are the electrical ratings?
The Dis Sub-12 SF6 is rated 12kV, 50Hz (60Hz optional), with 630A rated current on the main circuit and 125A on the fuse circuit. Short-time withstand current is 20kA/4s (main and ground circuit). Peak withstand current is 50kA. Power frequency withstand voltage is 42kV (phase-earth) and 48kV (isolated fracture); lightning impulse withstand voltage is 75kV and 85kV respectively. Vacuum circuit breaker breaking capacity is 20kA.
What is the delivery time and MOQ?
Standard configurations ship within 30-60 days from order confirmation. MOQ is 1 unit. Custom voltage ratings, protection schemes, or integrated FTU configurations may require 60-90 days. We accept sample orders for validation testing.
How does SF6 compare with SF6-free gas-insulated?
SF6 gas has higher dielectric strength, resulting in a more compact tank and lower cost for equivalent ratings. SF6-free gas-insulated RMUs use dry air and eco-gas with GWP ≈ 1, compliant with future EU F-Gas regulations. For markets with no SF6 restrictions and the highest priority on compactness and cost, SF6 remains the preferred choice. For ESG-sensitive projects or regions with SF6 regulations, choose our SF6-Free Gas-Insulated RMU →
Related Equipment
For a complete SF6 gas-insulated distribution solution, pair the Dis Sub-12 SF6 with:
- SF6-Free Gas-Insulated RMU — For ESG-sensitive projects and SF6-regulated markets
- YBM Prefabricated Substations — Containerized substations with factory-integrated RMU
- Remote-9001 Monitoring Unit — For smart monitoring and SCADA integration
- Medium Voltage Switchgear — For primary distribution switchgear applications
12kV / 630A / 20kA ratings
SF6 gas at 0.04 MPa sealed pressure
Annual leakage ≤ 0.01%
IP67 sealed stainless steel tank
30-year maintenance-free life
Modular C/F/V/PT/M/D configurations
Ready to Specify Your SF6 Gas-Insulated RMU?
Share your voltage rating, current rating, and module configuration — our engineers will reply with a tailored Dis Sub-12 SF6 configuration and factory-direct quote within 24 hours.
Request Quote NowCompare SF6 vs SF6-Free vs Air-Insulated →
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