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Innovative installation system

Innovative installation system

High voltage under the city

SAG Thepault has proven an innovative engineering spirit during the installation of 225 kV high voltage cables under the streets and homes of Marseilles.


The power grid operator Réseaux de Transport d‘Electricité (RTE) signed a contract with SAG Thepault for a specially challenging project. The task was to install 225 kV high voltage cables over a length of 1.6 kilometres underground in the heart of Marseilles. So far, this type and extent of work was unparalleled in France. For this purpose, SAG Thepault has designed and implemented an innovative installation system.

To lay the cables under the streets and homes, a tunnel was drilled initially in eight metre depth, in which the special PVC protective pipes with a diameter of 1.5 metres were laid. Afterwards, the transmission lines are installed through these pipes. They are fed over the entire length along special installation tracks to the endpoint.