Chester..
Thats the way I'd do it... 10/3w/ground from the 30A 2pole at your panel, Make up your 4 wire recept with the proper connections & you should be in the green [Linked Image] A bare conductor in romex is not meant to be a current carrying conductor, therefore I'd certainly rerun this with the proper amount of conductors

Welcome to ECN btw [Linked Image]

-Randy