To make this work correctly you I believe are showing a 10-2 -w- grd? To keep a balanced load you should run 10-3 -w-grd which will give you 2 hots, 1 neutral, and one grounding conductor. You will need to install a grounding lug in the panel. The only place you can ground the neutral is at the service. If the wire has already been run then install the black in one ungrounded lug and install a jumper to the next ungrounded lug. White to the Neutral Bar, and the bare to the grounding bar that you will need to purchase.