A £30m scheme to refurbish the overhead power line running between Landulph in South East Cornwall and Indian Queens, near Newquay, will start next month.
A total of 145 pylons will be fitted with new wire and painted as part of the project which is due to last until November.
The National Grid says that the work will help to maintain the electricity supply in the area and keep power flowing to homes and businesses for years to come.
The overhead line that runs between the sub-stations at Landulph and Indian Queens was built in the 1960s.
The wires have now come to the end of their working life and need to be replaced.
The first part of the scheme will see survey and exploration work at the pylon bases.
Engineers will clear trees and bushes, and temporary gates and stone pathways will lead to each pylon.
Refurbishment work is due to run from April until October before reinstatement of the land takes place.
The main depot will be near an industrial estate in Bodmin to avoid heavy lorries using narrow roads and village streets along the route.
Most of the work will take place between 7am and 7pm, with some work on weekends to get the job done as quickly as possible.