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Grid supply point substation update

In October 2022, National Grid’s planning application for a new grid supply point (GSP) substation at Butler’s Wood was approved by Braintree District Council. In this update, you can read more about our plans for the construction of the GSP substation, which forms part of the Bramford to Twinstead Reinforcement.


As a nationally significant infrastructure project, we will seek permission for the wider Bramford to Twinstead Reinforcement (overhead line and underground cables) through an application for development consent. We are due to submit this application to the planning inspectorate shortly.

Appointing a contractor and beginning construction activity

After planning permission was granted, we moved to appoint a contractor that would be responsible for building the GSP substation. The contractor we have appointed is J. Murphy & Sons, a leading specialist engineering and construction company. They will work on behalf of National Grid to build the GSP substation in accordance with the plans and conditions approved by Braintree District Council. We will work closely with the contractor throughout the construction period.

On-site activity began in March 2023, as members of our team carry out pre-construction surveys. These will include the completion of topographical and geotechnical surveys, along with a flood risk assessment.

We also expect to begin early enabling works shortly. These works will include the construction of site compound fencing, welfare facilities, vegetation removal and ground preparation.

We will then begin base installation works and start to construct some of the screening included in our planning application in the summer. Towards the end of 2023/early 2024, we plan to have built the temporary overhead line diversion required as part of the GSP substation’s construction.

We need to divert the existing 400 kV overhead line for around 700 metres near the GSP substation site, as our approved plans include the removal and relocation of an existing 400 kV pylon to the west of the GSP substation site. It is not possible to have an extended outage on this section of overhead line as the transmission network is already constrained in this area, so the diversion will enable construction of the new pylon and wider GSP substation whilst ensuring that electricity supplies continue to flow. The diversion will involve the construction of temporary pylons and will be in place for approximately one year. It is likely to be removed prior to the completion of the bulk of construction works for the GSP substation, which we expect to be by the end of 2024.

Next steps

We want to ensure that the local community is kept up-to-date on our activity. Throughout the construction period, we will share regular updates via our website and via email.

If you have any questions about this construction work or any element of the Bramford to Twinstead Reinforcement, then please contact us by email at [email protected], or by telephone on 0808 196 1515.