Schneider Electric helps restore Notre Dame Cathedral

The donated solutions have made it possible to secure and monitor the site's electrical facilities. The Building Management System (BMS) is thus able to manage and optimise the monument's energy consumption, incorporating 21st century innovations into a cathedral that represents a high point in medieval art, classified as a UNESCO World Heritage Site since 1991.  

The fire that severely damaged the cathedral on April 15, 2019, sparked an incredible wave of solidarity that Schneider Electric wanted to be a part of.  

"It's an obvious move for Schneider Electric to support actions of this type for symbolic and prestigious sites, as we have done in the past for the Comédie Française state theatre and the Antarctic station," highlights Gilles Vermot Desroches, Director of Citizenship and Institutional Affairs at Schneider Electric.  

Innovations for the future  

Schneider Electric provided expertise, products, and solutions thanks to a donation agreement. As such, the Group supplied all the equipment required to supply power to the site and for its security (20kV HV cells, a 20kV/410V 1250kVA transformer, general and divisional electrical switchboards, inverters, safety lighting, devices etc.), as well as the tools for the technical management of the building, making it possible to monitor the functioning of the network and control its power consumption (automatic control systems, sensors, controllers, communication buses etc.).  

In addition to the equipment, Schneider Electric is carrying out some of the maintenance of the electrical distribution equipment, providing some of the engineering, studies, commissioning, and programming of the installed systems, as well as the training of future users.  

The old electrical installation was inoperable due to the fire and without electricity, reopening was impossible. The new network ensures the distribution and security of the energy supply, incorporating innovative solutions and cutting-edge technologies that optimise the management of its electricity consumption and help ensure the safety of the cathedral.  

State-of-the-art fire prevention 

The project team opted for cutting-edge fire safety solutions:

• Additional devices for enhanced fire protection and prevention (Acti9 Active AFDD) for the socket circuits
• Overheating cable sensors (HeatTags) in all electrical cabinets

These two innovations ensure the facility functions properly through continuous monitoring and by sending alerts in the event of any changes, even before a problem occurs.  

A shared commitment 

The project team had to deal with a large number of technical issues demanding ingenuity and preparation.  

One such issue was the delivery and installation in early 2024 of the connected TRIHAL transformer, a key element of the cathedral's power supply. Delivered by truck and then raised onto the site above the construction area, this 3.2-tonne block was then lowered via a hoist into position in the basement of the presbytery. A specific study had to be carried out for the lifting operation.  

Installing the high-voltage substation in an underground vaulted cellar with considerable access and space constraints was also an issue resolved with customised equipment and support.  

"This is a project for which the logistics have been quite tricky and required excellent coordination with the other players on site," said Cédric Larcher, Regional Manager of the Electrical Distribution Application Centre at Schneider Electric France, responsible for management, performance and monitoring on site.  

In addition to providing infrastructure, around 60 Schneider Electric employees (from factory workers to the site’s network designers) contributed knowledge and expertise as part of a skills transfer programme. Schneider Electric’s support also included training partner companies such as the panel builder Ateliers Electriques de France (based in Val-de-Marne) to install the main low-voltage cabinet, FBS Electricité (based in Seine-Maritime) to install the high-voltage substation, ERM (based in Eure) to create specific support structures and Transport Avex (based in Val-de-Marne) to carry out the extremely tricky handling operations in the basement of the presbytery.