Power line alert to farmers in Yorkshire and Humber
Northern Powergrid said there had been several incidents in recent months involving tractors and other machinery striking cables or poles.
Contact with wires, carrying voltages as high as 400,000 volts, or as low as 230 volts, can be fatal.
The company said one incident involved a harvester hitting the conductor on an electricity pole.
The incidents have happened in Withernsea in East Yorkshire, Doncaster in South Yorkshire, Keighley in West Yorkshire and Catterick Garrison and Malton in North Yorkshire.
Paul Norton, head of safety for Northern Powergrid, said: "It's easy to misjudge heights and distances, especially when tired or in poor light such as at dusk or dawn.
"Another important point is that farm equipment spraying jets of water or pesticides can, if they come into contact with power lines, provide a circuit of electricity that can cause death or serious injury to the equipment's operator."