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, as we aim to complete these works in the first half of 2026. Please note, these works are subject to network outages and wider factors, such as bird nesting seasons.
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.
This work is being carried out by Morrison Energy Services, on behalf of National Grid.
Further information around planned work will be shared on this webpage.
Our work so far
Prior to the works commencing, 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.
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.
In December 2025, vegetation will be cleared to allow us to complete our work safely. We will construct temporary access routes for our teams.
Following this, we expect to be working in the area from 5th January 2026 until 1st April 2026. During this period, we will be repairing pylon steelwork and working at height to replace the overhead line.
As part of our work, you can expect to see:
access routes being established
delivery and construction of scaffolding at work sites
lines people working at height to replace overhead wires
repairs to pylon steelwork
temporary closure of some local parking spaces
vegetation clearance.
We anticipate that there will be minimal disruption across most of the areas where we are working. Our working hours will typically be 7am to 6pm, Monday to Sunday.
However, there are a small number of locations where more disruption is expected. We have written to the local community in these areas. These areas are as follows:
| Pylon to the south of Main Road B1137, Boreham (4VB058) | The team will be delivering and constructing scaffolding on land off the B1127, to the west of Boreham, and working at height to replace the overhead line. Temporary fencing will be installed around the work site to secure the area. |
| Pylon to the west of Cromwell Close, Boreham (4VB059) | The team carrying out the maintenance will be working on land behind residential properties on Cromwell Close. Temporary fencing will be installed around the work site to secure the area, this will not encroach upon the communal green space. |
| Pylons near to the l playing fields, Wickford (4VB11 and 4VB12) | The team carrying out the maintenance will be working on land north of residential properties on Beauchamps Drive. Whilst we are working on the overhead cables connecting the pylons, the public will be unable to walk underneath them, in order to maintain the safety of the public and our team. |
| Pylon at the end of Royal Oak Drive, Wickford (4VB010) | The team will be installing temporary fencing around our work site to secure the area. Unfortunately, this means that there will be no access to the garages and parking adjacent to Giddings Copse between Monday 9 February 2026 and 5 March 2026. |
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.