I know this subject seems to be debated to no end but I have a few questions/comments.
My main service panel is in my attached garage and I want to add a 100 amp subpanel about a foot or 2 to the side of it to power a mini split, air compressor, welder, and few other future tools for my garage workshop (mill/lathe/CNC router, etc)
I have a Square D QO load center as my main breaker with lug attachments rated at 75C and it looks like Square D rates their breakers for 60/75C service. Looking at 310.15(B)(16), I can get away with 3 AWG CU or 1 AWG AL wire rated for 75C but I just need to make sure the subpanel terminal lugs are rated for 75C as well. Correct?
I'd rather work with copper conductors since they will be smaller and easier to manipulate but I'm not finding a whole lot of 3/3 cable available. I also figure that using SE cable would be easier instead of messing with conduit unless I come in right below the original service panel and run the wire straight down into the subpanel with a short, straight piece of conduit. Don't know if there's any code against doing that or not (height issues). But if I did it that way, I could use individual 3 AWG CU wires which might be easier to source.