I just noticed my plug was a little brown, and took it apart. Wires didn't look so good. This is a 12ga extension cord with ends I put on after replacing the originals. The originals turned brown after a couple of weeks. I made the cable in 2011 for my Chevy Volt. It hasn't been used daily since then, but for the last 5 months or so it has been in daily service, charging the car every night. So, for anybody charging their Tesla on 120V (probably not too many but some), keep an eye on the cables you're using. And for those who will chime in "you shouldn't be using an extension cord", you might be right. But it won't stop people from doing it.