I am running power to an outbuilding 130' from main panel.Just need lights and a couple recepticals,planning on running 10-2. I have a outdoor rec. right above main panel which is about 3' of 12-2 and is the only thing on that circuit.Can I tie in to that rec. to keep from boring new holes through house? My concern was going from 12-2 to 10-2.Thanks for any help.