Thank you for the information.
But, I don't "string" wire with my drone. I pull string up over the tree to use as a pull cord to pull up the wire. The wire would end up being way to heavy to pull up.
As to part 107. I have no idea. I don't...
Weather you do it for free does not matter... You must be licensed to fly commercially to do it. That is why they call it "providing a service".. even at no charge it is unlawful for a recreational pilot to do anything other than fly for...