Why would the wire "flex" a "bunch of times"? I realize that you guys int he US really like those screw-in "wall warts", but isn't the screw supposed to discourage the customer from unplugging it? And wouldn't you use a plug that was "out of the way" and not prone to occasional use? Our contract stipulates that we must have a dedicated unburdened circuit for the panel. Around these parts we use a wire in transformer, and all solid core wires.