Only the plug wire shortened and connected with wire nuts. I would have just shortened it at the plug had I checked whether the plug would fit first...but I'm not that smart. The foam gasket they gave me was about a centimeter to long on one side so I had to shorten it with a razor on the bottom side. Don't understand why you can't shorten the other wire in the box, but I'm no electrical engineer either. It came with two new wire connectors so I assume you remove the wire at the light, shorten, add connectors, and reinstall cap. I looked at it and did not want to mess with that end since it looked tight and was bound to get wet. If I was determined I would put an outdoor junction box and shorten it there but I think I will wait till the timer and other plug is installed to decide.