Hello-
I am adding a 1500sq ft second story to my home. I have new 200amp panel on first floor. It is only about 1/2 used. I bought a 100amp panel for the upstairs. What size wire is needed to run from the downstairs 200amp, up to the 100amp panel. It is a distance of only 10ft or less.

Thanks in advance!
kamich70

In my area we would run #2AL SER cable. Some areas would require #1AL or #3CU.