I'm not sure how BIL does it - they live in Arizona and I'm in Indianapolis. DH pulls out the old wires and puts in new ones. He's done it on several. He has been doing electrical work for over 30 years so I don't ask questions unless I want to have to do it. I'm happy as a clam he will do it. I think there is info on sew-classic on wiring and you can buy wires from her.