In the rewiring of 50gal water heater replacing the 10-2 copper with 10-3 copper wire. the water heater had only two connecting wires; black and red. The white wire from the original 10-2 going to the heater was attached to the grounding screw noted on the top of the heater. In replacing with the 10-3 should I again attach the wht. neutral wire to the grounding screw and run the bare ground to a cold water pipe?