Thieves caused a power blackout in part of Kettering town centre when they broke into an electrical sub-station yesterday afternoon (Thursday) and stole copper cable.
Almost 400 properties, including a large number of businesses, were left without power between 1pm and 4.50pm, following the theft.
A spokesman for Western Power Distribution said: “Our engineers had to switch off the power for safety reasons and carry out repairs.
“It creates a dangerous situation when someone breaks into a sub-station. They are risking not only their own lives, but the lives of anyone who might come across the station when it is unsecured and those of the engineers – all for very small reward.
“The other consequence is the inconvenience caused to residents and businesses.”
Northamptonshire Police have been informed of the break-in.