Description
SF6 Gas-Insulated Epoxy Bushing (12/24 kV, 630A)
The SF6 gas-insulated bushing is the part that lets a cable meet a gas-insulated compartment. It passes the Type C 630A interface through the wall of an SF6 enclosure and seals it, so the switchgear inside stays a closed, gas-filled, dead-front volume while a cable connector plugs onto the outside. It is designed for European-type cable branch cabinets and power surrounding supply cabinets, and is used where a European-type cable branch cabinet connects onward to a high-voltage network.
The body is moulded from epoxy resin - an insulating compound with good electrical, thermal and mechanical properties that is environmentally stable - and presents the Type C 630A interface defined by CENELEC EN 50180 and EN 50181.
The bushing that seals the gas
The defining job of this part is not only to insulate - it is to hold gas. In an SF6-insulated cabinet the bushing is a pressure boundary: the inside face lives in the gas compartment, the outside face carries the cable interface, and the epoxy body between them must be gas-tight, dimensionally stable and dielectrically sound in both air and SF6. That is the difference between this bushing and an ordinary air apparatus bushing, and it is why the compound, wall thickness and sealing geometry are specified for gas-cabinet service.
Because the bushing carries the enclosure's gas retention duty, it is fitted once, during cabinet assembly, and stays in place through the life of the equipment while the cable connector is repeatedly plugged and unplugged on the outside.
Two faces, one part: gas side and cable side
| Side | What it presents |
|---|---|
| Gas side | the body and sealing surface that close the SF6 compartment |
| Cable side | the Type C 630A separable interface (EN 50180 / EN 50181) where a compliant cable connector plugs in |
| Screen | a moulded screen point for a drain wire (shield grounding) or a potential / fault indicator |
Construction
Interface - Type C, 630 A, as described by CENELEC EN 50180 and EN 50181.
Insulator - an epoxy compound with excellent electrical, thermal and mechanical properties, environmentally stable.
Screen - a convenient point to connect a drain wire (to ensure grounding of the connector shield) or to connect a potential indicator or fault indicator.
Electrical ratings, 12 kV and 24 kV
| Parameter | 12 kV | 24 kV |
|---|---|---|
| Continuous operating voltage | 10 kV | 20 kV |
| Maximum rating, phase-to-phase | 12 kV | 24 kV |
| AC withstand voltage, 5 min (60 Hz, crest) | 39 kV | 54 kV |
| DC withstand voltage, 15 min | 53 kV | 78 kV |
| Impulse withstand voltage | 95 kV | 125 kV |
| Minimum corona voltage level | 11 kV | 19 kV |
| Partial-discharge minimum extinction voltage | 15 kV | 20 kV |
| Rated current | 630 A | 630 A |
Dimension and mounting
Top connection: M16 × 2.
Bottom stud: M12 × 1.75.
Overall length: 202 mm.
Interface / flange diameters: Φ73 mm and Φ96 mm; locating steps 17 mm and 20 mm.
The kit
Each kit is supplied in a heavy-duty polyethylene bag and contains:
SF6 gas epoxy resin insulated bushing
Installation instruction sheet
Where SF6 gas-insulated bushings are used
Ring main units (RMUs)
The core application. A gas-insulated ring main unit uses SF6 to shrink its footprint and remove exposed live parts; the SF6 bushing is the interface through which the RMU's cable ways are connected while the gas volume stays closed. It is the standard way to give a sealed RMU a pluggable, dead-front cable connection.
Gas-insulated switchgear and compact switchgear (C-GIS)
Cubicle gas-insulated switchgear (C-GIS) and other compact gas cabinets use the same principle at panel level: the SF6 bushing carries the Type C 630A interface out of the sealed gas compartment, so panel builders get a standard separable connection without breaking the gas envelope.
European-type cable branch cabinets and power surrounding supply cabinets
Used in European-type cable branch cabinets and power surrounding supply cabinets where the cabinet itself is gas-insulated - including the case where the cabinet connects onward to a high-voltage network.
Connection to separable cable connectors
The bushing presents the Type C 630A interface, so a compliant (deadbreak) separable cable connector plugs onto its cable side, completing a dead-front joint from the sealed gas compartment to the cable.
Product display
Tell us your cabinet type (RMU / C-GIS / gas cable branch cabinet), voltage class, the connector you will plug in, and your screen requirement - we will confirm the correct bushing and quote the kit.
FAQ
Q. What is an SF6 gas-insulated bushing? It is a bushing that passes the cable interface through the wall of an SF6 gas-insulated compartment, sealing it so the switchgear inside stays a closed, dead-front gas volume while a cable connector plugs onto the outside.
Q. Where is it used (SF6 gas insulated bushing for ring main unit)? Most typically in gas-insulated ring main units, gas-insulated switchgear / compact switchgear (C-GIS) and gas-insulated European-type cable branch cabinets.
Q. How is it different from a standard apparatus bushing? A standard apparatus bushing insulates in air; this one must additionally seal and retain the SF6 gas - it is a pressure boundary as well as an insulator.
Q. What interface does it present? A Type C 630A separable interface per CENELEC EN 50180 / EN 50181, so compliant deadbreak cable connectors mate with it.
Q. What material is it made from? An epoxy resin insulating compound, electrically, thermally and mechanically stable and environmentally stable.
Q. What is the screen for? It provides a point to connect a drain wire (shield grounding) or a potential / fault indicator.
Q. What voltages and current is it rated for? 12 kV and 24 kV classes, 630 A.
Q. What standard is it tested to (SF6 gas insulated bushing IEC 60137)? Production tests follow IEC 60502-4 and IEC 60137.
Q. What is in the kit? The SF6 gas epoxy resin insulated bushing and an installation instruction sheet.
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