More than 400 properties are without power as fire crews tackle a blaze at an electrical substation in the centre of Exeter.
Devon and Somerset Fire and Rescue Service was called to the scene off Fore Street shortly after 6am on Sunday.
Crews are working to bring the fire under control and protect nearby properties, which have been evacuated, officials said.
The National Grid said 405 homes were without power on Sunday morning. Power had been restored to 491 homes.
The provider said the outage was caused by “third party damage” to its network, with power expected to be restored to all properties by 12pm.