Thieves stole 250m (273 yds) of power cables in Dorset after cutting down the wooden poles that supported them.
Dorset Police said the cables were stolen from the Castleman Trailway, a disused railway line, east of Ashley Heath, some time between 24 and 27 May.
Scottish and Southern Energy said the lines were not live at the time of the theft.
The incident happened off Verwood Road, near Holygrove Farm. Police are appealing for witnesses.