About 140 properties in a Northumberland town have been left without power after thieves broke into an electricity compound.
Copper components were removed from the substation on North Seaton Industrial Estate in Ashington late on Thursday.
Engineers from CE Electic UK are repairing the damage but warn power may not be fully restored until later.
The company said the thieves had risked their lives by ignoring danger of death signs and other security measures.
Peter McCormick, director of health and safety, said: "No doubt the thieves were lured by the prospect of making a quick buck, but by breaking in, they're lucky they haven't killed themselves.
"To the untrained and uninitiated, substations are potentially fatal, and in the past our staff have discovered charred bodies after similar incidents.
"This isn't just a massive inconvenience for everyone left scrabbling around in the dark.
"For some people, like those who rely on dialysis machines, a power cut can result in serious health problems or even death."
Properties affected are in Brecon Close, Chiltern Island Way, Chiltern Close, Chiltern Drive, Freeman Way, Lowther Close, North Seaton Industrial Estate and Pentland Close.