The power distro that I built has 5 20 amp circuits and 4/4 cable. Maybe I could add one more circuit to it and get a hubbell connector. The problem is getting someone to tie it in. Do you have a link to the hubbell that you are using? Are you talking about a single hubbell connector that will take 4/4 copper? I would be very interested in seeing it as it would make a few thing easier for me.