This subject sure has drifted, but since it has I would like to comment that I don't think the derating rules in 310.15(B)(2) apply to the gutter space in panels. I'm sorry, but I don't believe the intent was to apply these rules to panels because if we do most panels out there would not pass inspection. we would be derating every conductor in the panel. Now someone explain to this group what maintaining spacing is all about.
