Louisville Gas and Electric Company says it will make some power source switches downtown Sunday.Spokesperson Chip Keeling says LG and E is dismantling a facility at Second and Main Streets to make way for the new arena."This is a major step in the movement of the arena project, which will allow us to move the old substation over to the new substation and do a changeover of that system," he said.Keeling says the switchover of power should not cause any disruptions, but customers who live in the area between Floyd and Ninth Streets and from River Road to Chestnut Street are advised to back up their computer data as a precaution.The work will begin at 5:00am Sunday and continue through early evening.