I am installing a 100A subpanel to a detached workshop and would like 220V. I naively followed the advice from the electrician working in the local Home Depot when buying the wire. I purchased 2/2/4 aluminum direct bury but now believe I should have purchased 2/2/2/4 in order to have 220V. The cable has been buried and I would really prefer not to bury a forth cable. The work will not be inspected but I desire to install the subpanel properly. I live in Norfolk, Virginia. I do not expect to need 100A so I can drop down to 70A if necessary. I suppose this would require me to ground off each panel, which I don't believe is a good idea. Please let me know if I have any options other than running 110V. Thank you.