Firefighters battled a blaze in an electrical sub-station last night.
The fire broke out at the sub station in Plymouth Road, Liskeard at about 9.45pm.
Cornwall Fire and Rescue Service crews from Liskeard, Callington, and Looe were sent to tackle the emergency.
They found smoke pouring from the premises.
Firefighters wearing breathing apparatus out out the flames the fire using dry powder extinguishers and worked with electrical engineers to make the scene safe.