PFISTERER’s CONNEX System: Extensive Qualification Experience and Ongoing Development for SF₆-Free GIS
Paris, August 24rd. As Europe's revised F-Gas Regulation (EU) 2024/573 sets firm deadlines for phasing out sulfur hexafluoride (SF₆) from electrical switchgear – starting with medium-voltage equipment in 2026 and reaching high-voltage systems above 145 kV by 2032 – PFISTERER has taken a concrete step to prepare the market: its CONNEX connection system has been continuously developed and qualified across a growing range of applications for connecting Gas Insulated Switchgear (GIS) and transformers using insulating gas technologies that go beyond SF₆. PFISTERER brings extensive experience in this field, having successfully completed numerous qualifications to date – and the process is ongoing, as the company continuously addresses new applications and evolving technical requirements.
SF₆ has long been the reference standard for insulation in GIS installations, valued for its exceptional dielectric strength and reliability. But with a global warming potential 23,500 times that of CO₂ and an atmospheric lifetime of approximately 3,200 years, it is also one of the most potent greenhouse gases in industrial use. Replacing it is one of the most concrete, measurable steps the power sector can take toward its 2030 climate commitments.
The transition, however, is technically demanding. Alternative insulating gases – including natural-origin gases such as nitrogen, CO₂ and synthetic air, as well as fluorinated mixtures based on C4F7N (fluoronitrile) or C5F10O (fluoroketone) – have lower dielectric strength than SF₆, requiring higher operating pressures and, in some cases, larger equipment dimensions. Higher pressures place increased demands on enclosure design, sealing systems, pressure monitoring, and material compatibility.
These technical challenges are also reflected in ongoing standardization work, in which PFISTERER is actively involved and among the leaders in the industry.
The revision of IEC 62271-209, the international standard defining high-voltage cable connections to gas-insulated switchgear, is currently underway, with PFISTERER experts providing insights, strong participation, and support. At the same time, Pfisterer is contributing to the groundbreaking CIGRE Working Group B1-88, which is developing a Technical Brochure on cable accessories with non-SF6 gases. This work is expected to be completed by the end of this year and will provide the industry with guidance on addressing the challenges of the transition to SF6-free, ecofriendly alternatives.
As a recognized expert in this field, PFISTERER brings decades of expertise in high-voltage connection technology. The company has successfully qualified the CONNEX system across multiple applications to meet the technical and safety requirements of the new generation of SF₆-free GIS – providing manufacturers and network operators with a proven, safe connection solution that is already built for the grid of the future. And qualification is an ongoing commitment. As new applications, voltage classes, and gas-pressure combinations emerge, PFISTERER continues to systematically advance and expand its qualification work, ensuring that the CONNEX system keeps pace with the evolving needs of the market.
“Responsibility is embedded in every connection we make at PFISTERER, and it guides everything we do. As a partner for mission-critical infrastructure, we bear responsibility toward our customers, our employees, society, and future generations. We are committed to sustainability and innovation across all our products." said Dr. Konstantin Kurfiss, Member of the Executive Board at PFISTERER
PFISTERER's CONNEX system is used for pluggable connections between high-voltage cables, transformers and gas-insulated switchgear (GIS) in transmission and distribution substations.
The company presents its approach at Level 3 | C71 at CIGRE 2026.