Reckless thieves cheated death when they broke into an electricity sub-station in Preston and blacked out more than 1,100 homes and businesses.
Engineers say the intruders caused £30,000 worth of damage after sparking an intense fire which destroyed the unit in Kent Street.
The locked substation doors were broken down and and unsuccessful attempt was made to steal an amount of copper wire.
“This incident was very serious,” said Martin Deehan, operations director at Electricity North West.
“A huge amount of damage has been caused to the substation and the culprits who entered cheated death.
“I’d be amazed if they left the scene unharmed.”
The intruders broke in at shortly after 5am last Wednesday. As they tried to rip out cables they caused a fire which cut power to 1,149 customers.
Fire crews put out the blaze and Electricity North West say they were able to restore supplies to around 1,000 customers by 7.44am, with the rest re-connected by 12.30pm.
Martin Deehan added: “There is a reason we have yellow ‘danger of death’ signs in and around the electricity network.
“People must take note of these and stay away.”
It took Electricity North West engineers 24 hours to carry out a full repair to the substation.
Police say they are investigating the burglary and the damage caused and have issued a public appeal for information which could help to identify those responsible.
A spokesperson said: “Attempts have been made to steal some copper wiring, which caused a fire. No arrests have been made.” Anyone with information can call 101, quoting log 0162 of October 23.
Electricity North West is the network operator for around 5m people in the region.