This is the www, and people come here to learn, so I am sharing my observations. If you stress a piece of wire, any wire, it develops little cracks. We all know this already. Here in Canada, we use 15 amp circuits and #14 copper for most residential wiring, so that is why I tested #14. I am not trying to prove I'm right in the normal anal sense, because if the wire did not break after folding it and unfolding it twice, I would have said so.