Laying an underground line

Throughout all its projects, Elia ensures that it takes all necessary measures to limit the work’s impact, preserve the environment and maintain residents’ quality of life. 

Stages of work

Elia generally lays new underground lines in seven stages.

  • Stage 1: Holding a coordination meeting

    Elia organises its projects in collaboration with the local authorities, the police, the managers of public areas and its contractors with a view to minimising the impact on mobility.

  • Stage 2: Conducting a survey

    Elia conducts a survey (including the roads and paths along the line’s route) with the relevant authorities and contractors and commits to restoring the infrastructure to its original state once the work is complete.

  • Stage 3: Putting up signs

    Appropriate diversions and signs are put in place in consultation with the local police.

  • Stage 4: Digging trenches

    Trenches are dug and reinforced over a length of around 1 km.
    Open trenches are not used in some locations (e.g. under railways, or under major roads or intersections); directional drilling is carried out instead.

  • Stage 5: Pulling conductors

    The cables are then pulled through the trench.

  • Stage 6: Repairing roads

    After the cables are laid, the trenches are backfilled. Finally, the site is cleared up with a view to returning all affected areas to their original state.

  • Stage 7: Conducting a final survey

    Elia conducts another survey with the relevant authorities and the contractors, just as it did before the work began. This time, the survey’s purpose is to ensure that the site has been restored to its original state.


Organisation of the work

Respect for local residents and the environment is a priority for Elia. While every project is different and very much depends on the type of infrastructure involved, Elia always organises its work in collaboration with all relevant parties (including the contractor, the local authorities, the local police and landowners) and regularly updates local residents on the progress being made.

While work is ongoing, Elia implements a series of measures focused on three key areas: safety, noise control and mobility management.

  •   Noise control
    • Noisy work is carried out during working hours, unless otherwise agreed with the relevant authorities with a view to reducing the impact on mobility at specific times.
    • Site vehicles only leave their engines running when necessary. 
  •    Site safety
    • Work areas are always marked out clearly and a site safety coordinator is always on hand to ensure that activities on the site run smoothly.
    • Furthermore, site meetings are held with contractors to discuss points for attention (e.g. itinerary, waste sorting).
    • When the existing line is being dismantled, safety gantries are put in place while the power cables are pulled to protect infrastructure along the route (roads and homes). 
  •    Mobility
    • If the work requires temporary road closures, appropriate diversions and signs are put in place in consultation with the local police.
    • Work-in-progress signs are erected in dialogue with the local police. These signs provide residents with all the information they need (in particular, the start and end dates for the work).
    • Elia strives to ensure that local residents always have access to their homes.


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