Underground electrical connection between LHC Points 6 (Versonnex) and 5 (Cessy)

2024 - 2025

plan de localisation ligne electrique

In preparation for the High-Luminosity LHC, CERN will construct an underground electrical connection between LHC Points 6 (Versonnex) and 5 (Cessy) in 2024

The work will begin in early 2024 and is expected to last 12 months. A trench measuring a maximum of 1.5 metres in width will be dug to accommodate a 66-kV underground electrical line, and the 66-kV substations at LHC Points 5 (Cessy) and 6 (Versonnex) will be upgraded.

It has been decided that this new electrical connection should run underground for ecological reasons and to preserve the landscape. The route of the connection has also been designed to limit the impact on the environment and on local residents. All measures have been taken to keep disruption to a minimum during the works.

The project is of crucial importance for the High-Luminosity LHC (HL-LHC) collider project, an upgraded version of the LHC that will enter into service after 2028, increasing the volume of data available to the ATLAS and CMS experiments by a factor of 10. To stay up to date with developments on this major project, keep an eye on the webpage dedicated to the work being done in preparation for the High-Luminosity LHC (HL-LHC)