Project overview
We are replacing two transformers at the National Grid Exeter Substation site.
The substation contains specialist equipment that allows the voltage of electricity to be transformed or ‘switched’. The voltage is stepped up or down through pieces of equipment called transformers, which sit within the substation’s site.
Transformers are electrical devices that transfer electrical energy by means of a changing magnetic field. They consist of two or more coils of wire and the difference in how many times each coil wraps around its metallic core will affect the change in voltage. This allows the voltage to be increased or decreased, so that electricity can be efficiently transmitted from power generators depending on where electricity is in its transmission journey.
The current transformers have reached the end of their operational life. We’re upgrading the equipment to ensure future stability and resilience on the network across the south west.
The Exeter Substation upgrade that will commence in October 2025 will increase the substation’s voltage control capability to reinforce the network in the region in anticipation of future demand growth.
Works are expected to cause minimal disruption to the local community.
Contact us
Our team is on hand to answer any questions you have. If you want to find out more about the project or have any questions, please do not hesitate to get in contact via one of these channels:
- Email us at [email protected]
- Call our freephone on 0800 099 6097 (between 9am and 4:30pm Monday to Friday)
What you can expect to see
Over the coming months, National Grid and its contractors will begin the process of preparing the site for the arrival of the two new transformers. This will include the delivery of equipment, establishing welfare facilities, dismantling and removing existing transformers, installation of new equipment, as well as the delivery of the new transformers.
Our working hours will be:
- 07:00 to 17:00 Monday to Friday
- 18:00 to 19:00 latest finish time
The work will be carried out by Envolve Infrastructure on behalf of National Grid.
Works are expected to cause minimal disruption to the local community. An increase in construction-related vehicles in the area is expected, particularly at the start of the works and around the delivery of the SCT and EAT transformers, which is planned to take place in December 2025. The SCT transformer will require an Abnormal Indivisible Load (AIL) delivery, that may bring impacts along the transport route and for some distance away from the substation.
- Autumn 2025 – site mobilisation, equipment delivery, removal of existing SCT and EAT transformers and preparation for the delivery of the new transformers.
- Winter 2025 – delivery and installation of transformers.
- Winter 2025 / 2026 – connection of transformers and installation and maintenance of other equipment on site.
Frequently Asked Questions
National Grid owns and operates the electricity transmission network in England and Wales.
National Grid is replacing two transformers located on the Exeter Substation site, as the current transformers have reached the end of their operational life. This will enable us to meet the growing demand for electricity and support the development of clean energy in the UK.
The Exeter Substation upgrade that will commence in October 2025.
One of the main role of substations is to convert electricity into different voltages. Substations contain specialist equipment that allows the voltage of electricity to be transformed or ‘switched’. Transformers allow the voltage of electricity to be increased (stepped up) or decreased (stepped down). Transformers transfer electrical energy by means of a changing magnetic field. They consist of two or more coils of wire and the difference in how many times each coil wraps around its metallic core will affect the change in voltage. This allows for the voltage to be increased or decreased.
This voltage adjustment is essential for the safe transmission of electrical power along the network, allowing energy to be sent over long distances across the UK at high voltages, so that it can be lowered for safe use in our homes and businesses.
Over the coming months, the team will begin the process of preparing the site for the arrival of the two new transformers. This will include the delivery of equipment, establishing welfare facilities, dismantling and removing existing SCT and EAT transformers, installation of new busbars and earthing rods, as well as the delivery of the new SCT and EAT transformers.
Our working hours will be:
- 07:00 to 17:00 Monday to Friday
- 18:00 to 19:00 latest finish time
The work will be carried out by Envolve Infrastructure on behalf of National Grid.
- Autumn 2025 – site mobilisation, equipment delivery, removal of existing SCT and EAT transformers and preparation for the delivery of the new transformers
- Winter 2025 - delivery and installation of SCT and EAT transformers
- Winter 2025 / 2026 – connection of new transformers and installation and maintenance of other equipment on site. The new transformers and installation of other required equipment on site
Planned works at Exeter Substation are expected to have minimal impacts to local electricity supply.
Planned works at Exeter Substation are expected to have minimal impacts on local residents.
Residents may notice an increase in construction-related vehicles in the area, particularly at the start of the works and around the delivery of the SCT and EAT transformers, which is planned to take place in December 2025. The SCT transformer will require an Abnormal Indivisible Load (AIL) delivery, that may bring impacts along the transport route and for some distance away from the substation.
Do not hesitate to get in contact via our dedicated communications channels:
Call us: 0800 099 6097 (available 9am – 5pm Monday to Friday)
Email us: [email protected]