A ceiling outlet is certainly a good way to go, but there are some considerations:
- Surge suppression. Do you have a whole house surge suppression system? your long arm is an expensive piece of equipment that you want to protect, especially if you have or plan to have a computer assisted setup.
- position. You want the outlet to be centered and towards the back of your frame, otherwise the cord can get caught on the machine as you move it.
What I did was plug a surge suppressor into a floor outlet, then I connected the long arm to that with a heavy duty (12 gauge) extension cord. I used bungee cords & hooks to arrange it so that it didn't get hung up on the machine. I quilt in the basement, so moving hooks around the unfinished ceiling didn't disturb the decor. It took several attempts to get the cord positioned so it didn't interfere as I moved the machine.