Firefighters from Liskeard, Callington, and Looe battled a blaze at an electrical sub-station in Liskeard last night.
The fire broke out at the sub station in Plymouth Road, Liskeard at around 9.45pm.
A Cornwall Fire and Rescue Service spokesperson confirmed: "Pumping appliances from Liskeard, Callington, and Looe were mobilised to this incident.
"On arrival it was confirmed that smoke was issuing from the premises and that there was a fire inside an electrical substation."
Firefighters wearing breathing apparatus extinguished the fire using dry powder extinguishers and worked with electrical engineers to make the scene safe.