how do you replace three prong 220V outlet with four prong outlet?

Answer 1

You can only do this if the wiring exists to do it. A 3-wire system only requires 2 - hots and a ground. The 4-wire system requires 2-hots, 1-neutral and a ground.

You need to turn off the power, verify that the power is off with a volt meter, open the outlet that you want to replace and determine if you have 3 or 4 wires in your box. If there are only 3 wires, you need to run a new 3 conductor cable with ground to install the four prong outlet.

If there are 4 wires, then it is your lucky day and you can just replace the outlet.

Answer 2

will try to explain this to you, first I take it that you will be doing the job. ok, a three prong plug uses 2 110 circuits thus the black and red, usually the white neutral and green or bare gound are tied together if it has four wires, in a four prong the white and green/bare are seperated, but unless your a hospital or lab these are tied together at the same busbar in your electrical panel anyway, now should you have a heavy duty wire meaning two black wires and an aluminum/silver stranded wire the blacks are your hots and just seperate the strands into a couple of strands each and put them into the neutral and ground spot. Why you have two 110 circuits are because nothing runs on a true 220 but two 110s adding up to 220 at that box,ex; a dryer is 220 with 110 for the controls and the other 110 for the heating element but 220 is required, hope this helps

Answer 3

Simple dude...break the 4th one and use it..:)