Air insulated switchgear
High-quality AIS – air insulated switchgear: DF-2(+)
We engineer reliable switchgear built on safety and durability
It’s our most popular product: the “DF-2”, is a metal-clad and high-quality AIS switchgear solution. A modular concept which combines all medium voltage functions. It allows us to provide “made-to-measure” solutions for all your medium voltage needs.
Modular design
2-position load break switch
Arc-killer option
The DF-2 system is a modular concept based on the “building blocks” principle, which means that cubicles are produced in series. As a result, the modular DF-2 concept meets the highest technical standards in a rational, economically sound way.
The combination of cubicles is unlimited. Very complex diagrams of distribution and transformer switchgear can be compiled through this extensive spectrum of possibilities. Our AIS solutions are always extendable, compartmentalized and can handle up to 24 kV.
The DF-2 cubicles and associated air insulated switchgear solutions offer a wide range of applications and can be used worldwide in many industries. DF-2 cubicles can be utilized with distribution and dispersion switchgear, electrical sub- stations and medium voltage engines, wind generators, cogeneration, and much more.
The DF-2-concept provides a solution for all your needs and demands: it can replace obsolete installations and extend existing installations, and it is also perfectly suitable for entirely new constructions.
Moreover, it’s built to withstand extreme conditions, maximize the life of your switchboard and guarantee operator safety.
Modular air insulated switchgear: The DF-2 system
- Air Insulated Switchgear: metal enclosed AIS cubicles with galvanized steel sheets 2mm and between the compartments 4 mm
- Modular system – expandable - combination is unlimited
- High operator safety
- Switching in SF6 for switch or vacuum circuit breaker
- Stand alone cubicles – high continuity
- Built to withstand extreme weather conditions
- Can be equipped with a wide range of optional features
Equipped with a robust two-position load break switch RV-44 (open or closed), that is sealed for life. Can withstand a pressure of 800 A and optional 1250 A (double busbar system). DF-2 ’s modular design allows you to create rational, economical & custom-made combinations of medium voltage cubicles (with a rated voltage 12,17 or 24 kV). The position of the load break switch is clearly indicated in the single line diagram. The position can be controlled at all times, not only by the synoptic but also through the two inspection windows integrated in the front door of the cubicles. This kind of load break switch has large contacts and can withstand the voltage with pressure.
Internal arc resistance
The DF-2 is designed to resist internal arcs, protecting both the operator and the installation. Through a strategic pressure release system, the internal arc is restricted to the compartment where it originated, and it does not propagate towards the operator or to other compartments. A short-circuit or another malfunction can create an internal arc. An internal arc in a classic MV cubicle, could severely damage the installation and possibly injure the operator and electrocute him or her. With built-in ARC-killers SGC aims to protect its users and operators.
The anti-arc kit of DF-2 cubicles is specifically designed to minimize the consequences of an internal arc. By default, all provided cubicles are fitted on the rear side with overpressure valves pointing downward. Moreover, all SGC – SwitchGear Company cubicles are internal arc resistant. The DF-2 cubicles were tested at KEMA IAC (AFL) FOR 20 kA/1s as well at a rated voltage of 17,5 kV/24kV according to IEC 62271-200, appendix A and met the 5 criteria.
How can you protect yourself from electric arcs? Read more here.


Our DF-2 AIS product line
Discover the product that’s right for you. SGC helps you choose the best solution. Our DF-2 range is our most popular product range, and it’s popular for a reason. Our DF-2 range is especially designed and built to withstand extreme weather conditions. It’s applicable in all parts of the world, whether there are extreme cold or extreme hot temperatures. It’s built to last: all components are robust and of the highest quality.
Guaranteed operator safety, co-engineering and long-lasting quality are some of the reasons why SGC is a preferred partner. Want the top of the range with built-in ARC-killer? Then go for the the DF-2+. The DF-2+ includes the arc-killer SV-25, a system for detecting and extinguishing an internal arc.
A DF-2+ is a metal-enclosed cubicle of the DF-2 type combined with a shaft at the rear of the cubicle. The shaft absorbs the gasses (in case of an internal arc) that escape through the overpressure valves. As a result, the expansion of hot gasses in a room can be reduced to an absolute minimum. The arc-killer extinguishes the arc by directing it to a metal earthed short circuit. The arc is extinguished in less than 50 ms.
Want more information? Our team is here to help.
Want more information? Our team is here to help.
Technical specifications
Rated voltage | kV | 12 | 17.5 | 24 |
Impulse withstand voltage 1.2 / 50 μs: | ||||
- To earth and between phases | kV | 75 | 95 | 125 |
- Over the insulated distance | kV | 85 | 110 | 145 |
Power frequency withstand voltage: | ||||
- To earth and between phases | kV | 28 | 38 | 50 |
- Over the insulated distance | kV | 32 | 45 | 60 |
Rated frequency | Hz | 50/60 | 50/60 | 50/60 |
Rated current | A | 800/1250 (*) | 800/1250 (*) | 630/800 |
Rated short-time current 1s | kA | 25 | 25 | 20 |
Rated peak value of the current | kA | 63 | 63 | 50 |
Breaking capacity RV44 (class E3): | ||||
- Mainly active load | A | 800/1250 (*) | 800/1250 (*) | 630/800 |
- Closed loop | A | 800 | 800 | 630/800 |
- Load cable charging | A | 18 | 18 | 18 |
- Making current | k | 63 | 63 | 50 |
- Earth fault | A | 100 | 100 | 100 |
- Earth fault cable charging | A | 30 | 30 | 30 |
Internal arc 1s | kA | 16/20 (**) | 16/20 (**) | 16/20 (**) |
Degree of protection | IP4X | IP4X | IP4X | |
Mechanical durability c/o | 1000 | 1000 | 1000 | |
Standards: IEC 62271-100, IEC 62271-1, 62271-102, -103, -105, 62271-200 and IEC 61243-5 | ||||
Certificats: KEMA/IPH |
(*) According to IEC 62271-103, class E1 / (**) Option Arc-killer
Our DF-2 cubicles can be used in a wide range of configurations
DF-A
Incoming cubicle or cable field with load break switch and interlocked earthing switch
DF-P
Transformer protection cubicle with load break switch/fuse combination
DF-C-750
Metering cubicle
DF-K
Cable cubicle and/or rail shaft
Digital Protection Relay RP800
The protection cubicles of our DF-2 AIS range can be equipped with an integrated digital protection relay RP 800.
To find more info about which cubicles download our DF-2 brochure with all technical specifications of our cubicles.
The protection relay is made by our sister company Mevoco. Mevoco produces all the components used for our switchgear cubicles.
Working together with this partner within the same holding helps us to assure quality of our end product.
DF-2 projects
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