Since January 2023, we have been undertaking essential maintenance work on the 400 kilovolt (kV) overhead electricity transmission line between Twinstead Tee and Rayleigh substation in Essex.
The project is now in its final stages and the remaining work that was scheduled to take place between January and April 2026 has now been postponed at short notice because our outage was cancelled by the National Energy System Operator (NESO).
An outage is a planned period during which we temporarily switch off parts of the electricity network so that work can be carried out safely, without disrupting your electricity supply. The majority of the remaining work for this project must take place under an outage to ensure we can complete our activities safely.
The NESO is responsible for managing outages on the electricity transmission network. We are working to secure new outage dates and will share further details with you as soon as they are confirmed.
Specific and focused maintenance works may be carried out whilst we await a response from the NESO. If confirmed, we will update this webpage prior to the start of any work taking place.
In the meantime, you may still see M GROUP working in the area, on behalf of National Grid. This is because in some areas the temporary trackway is being removed.
These postponed works are in relation to one side of the pylon, referred to as ‘circuit 1’. This is separate to another National Grid project Pelham to Rayleigh Overhead Line Reinforcement, which involves works to the other side of the pylon, referred to as ‘circuit 2’. This project is progressing and at an earlier stage of development. More information about the Pelham to Rayleigh Overhead Line Reinforcement can be found on its project webpage here.
Further information around planned work will be shared on this webpage.
Our work so far
We completed environmental and technical surveys to help us prepare.
Maintenance activities have already been carried out on some sections of the route and this included:
- refurbishment of overhead lines
- steelwork repairs on pylons
- replacing fittings to ensure the line's reliability.
Maintenance work on transmission lines is carried out on one side of the overhead lines and then the other, in a loop. This means we will be returning to some of the same areas that you may have seen us working in before.
When completed, the new conductors will be capable of carrying more power, helping to transport cleaner and more affordable sources of energy from where it is generated to homes and businesses.
What’s next?
This work will take place under planned outages, which are scheduled power line interruptions to allow safe maintenance and upgrades to be carried out across the network. These outages will not affect your electricity supply.
We are working to secure new outage dates and will share further details with you as soon as they are confirmed.
Keeping you informed
We will update this website as we carry out the rest of the project to let you know where you might see our team working. For some areas, updates will be provided via post before we start our work. If you have any questions, you can get in touch with the team by calling 0808 304 1534 or by emailing [email protected].
Thank you for your patience as we undertake these vital works.
National Grid's Community Grant Programme
Our Community Grant Programme is aimed at organisations and charities in areas where National Grid’s work impacts local people through our operations and site activities.
We fund projects run by charities and community groups that meet local community needs, by providing a range of social, economic and environmental benefits.