Vandals who have carried out 17 attacks on electricity substations are endangering their lives, police have said.
Security has been stepped up at sites in the Tandridge and Redhill areas of Surrey in response to the incidents.
But police and electricity suppliers EDF Energy, until recently known as Seeboard, said vandals were continuing to damage substation premises despite warnings before Christmas.
A spokesman for Surrey Police said: "In one recent incident, vandals were within a whisker of coming into 11,000 volts of electricity - the results of which would have been fatal."
The attacks have also disrupted power supplies to homes and business.
Between the end of November and Christmas, there were 13 incidents, with a further four this month.
Barry Hatton, EDF Energy's head of network services, said those responsible were using heavy duty cutting equipment to break into substation premises.
He said: "It is only a matter of time before luck runs out for these vandals.
"At best they will then be looking at a hefty fine or prison sentence, as we are working very closely with the police.
"At worst, their reckless actions could result in death."
Anyone with information is urged to contact Surrey Police.
EDF Energy operates 70,000 substations across the South East, East and London.