I looked in article 530 and 230. So it's going to be under 50amps being used inside so I was thinking surface mounting a small panel outside, and connecting a S/O cord to it and back feeding the panel with it. Would this be acceptable? I was thinking the S/O cord should be GFCI protected always. Do they make a GFCI plug I could attach to the S/O cord? Thank you for your help.