Protesters are calling on the company to rethink the route
Campaigners opposing plans to install 400,000 volt power lines through a North Somerset valley say National Grid should rethink the route.
Save Our Valley group said the power company had come up with the lowest cost option for the company, but not for the people living along the route.
"We're telling them to go away and reconsider a route under the sea or underground," a spokeswoman said.
The pylons will link a power station at Hinkley Point to Avonmouth.
Protesters took part in two walks on Saturday morning.
Both started at 1100 GMT, one from Parish Brook Road, Nailsea, the other from Backwell Lake.
Organisers say they were chosen to highlight the two options which have been proposed for the pylons and cables.
The first would see some of the existing power lines to the west of Nailsea in the Causeway area replaced.
In the second option, new lines would be built running south of Nailsea across Youngwood Lane, Backwell Lake, Backwell Common, before turning north across Wraxall.
National Grid hope the project will be in place by 2016.
The company has been asked to connect a nuclear power station which is to be built close to the existing generating plant at Hinkley Point.
A company spokesman said the overhead pylons were the most economical option.