CONNEX – The Universal Connection System for Cables, Transformers, and GIS

The fully encapsulated CONNEX connection system with solid insulation makes power transformers and GIS more flexible than ever before: in terms of design, set-up, and application. With CONNEX, systems become compact all-rounders, ideally equipped for new requirements in the future. How do you benefit? Systems remain flexible over the long term, securing your investment throughout the entire service life.

Flexible for network adjustments

The trend is clear: Substations are becoming more compact while network infrastructure is becoming more dynamic. Not a problem thanks to CONNEX! The connectors are easy to insert – even power transformers and GIS can be installed or replaced with ease. Featuring a space-saving design for indoor and outdoor use, CONNEX can even be used off-shore and is ready to tackle new challenges.

A CONNEX interface for every connection.

CONNEX forms a single unit with transformers and GIS. The socket is installed as a fixed system component and serves as a standardized interface for various components, such as bushings or surge arresters. This significantly reduces your workload as you no longer have to worry about dealing with the system’s sensitive inner workings.

CONNEX is the biggest product line on the market.

With CONNEX, PFISTERER covers all voltage ranges between 6 kV and 550 kV. The plug-in connection system includes a wide selection of cable accessories, surge arrestors, bushings, joints, and voltage testing systems, along with installation and test accessories. This makes it the most extensive product range on the market.

CONNEX is the only system certified for off-shore use.

CONNEX is a pioneering plug connector for transformers and GIS in open-air and building-based applications. Furthermore, it is the only connection system to have received certification for off-shore applications from the DNV GL classification company, making it ideally suited for use on open-sea platforms and wind farms.


  • 75% less time needed for initial installation
  • Modest space requirements
  • Suitable for outdoor and indoor use
  • Speedy change of location as replacement transformer
  • Potential for flexible transformer conversion
  • Touch-proof maintenance
  • Good protection against electromagnetic fields
  • Certified for off-shore applications
  • Safety tested according to IEC standards


The new power transformers from AVU Netz GmbH are universal in their application. This network operator in western Germany is already implementing three connection versions using identically constructed transformers and thus remaining flexible for future demands. This is made possible by the versatile CONNEX connection system.



Space-saving, innovative, underground. The Oerlikon substation uses intelligent, vertical connection technology by PFISTERER to free up building space.


When designing the Klus substation, personal safety was given number one priority because quick maintenance means maximum reliability, just as you would expect in Switzerland. CONNEX also reduces costs, just as you would expect from PFISTERER.


Kraftwerke Oberhasli AG (KWO), a Swiss energy supplier, runs some of the most powerful hydropower plants in Europe but some of the plants have started to show their age. For the upgrades, the operators relied on PFISTERER technology.



Q7 is the Netherlands’ first off-shore wind farm outside of the territorial zone (12 nautical miles). Here, CONNEX cable connections are not the only things that need to show off their sea legs. PFISTERER experts have to showcase their bravery, too.


The cable system in the dry dock, the test transformer far away on the back of the truck. HV tests for off-shore systems can be pretty tricky. A PFISTERER-developed adapter solves this problem.


14 staff, 13 weeks, 5,800 meters of cable: PFISTERER installed the first ever cable system certified for off-shore use at the Global Tech I off-shore wind farm.


The Park Substation built by Anaheim city council in California is the USA’s first distribution station to be built underground. Also in on the action: the CONNEX connection system by PFISTERER.


Quick and long-lasting renovations? All it takes is a few steps thanks to the IXOSIL joints by PFISTERER. No clamping rings, no pipes, no flanges. Simply remove, fit, and save time.