Just bought a house and the recepticle for the dryer in the laundry room is a 3 prong 50a 240v receptical. The associated breaker is 30a. I need to change the receptical to a thirty amp that I picked up at Lowe's. The question I have is how to wire it. The existing wiring is black, white and bare, and was wired as follows: black to the left, white to the right and bare at the bottom. The directions on the box tell me to wire the neutral wire to the silver screw and the black to each of the copper screws. Does new wire need to be pulled? Or can I (within code and safely) just change the existing dryer pigtail to a 3 prong 50a pigtail?