Range Outlet: 3-wire vs 4-wire


Old 03-06-01, 12:46 PM
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The wiring in my kitchen is being upgraded. Currently, my old range uses a 3-wire 240V outlet; however, I've noticed that at least one new range model (Maytag Gemini) uses a 4-wire outlet. What is the difference between 3 and 4 wire connections? If the 4-wire is the new standard, would it be better to setup my old range to use 4-wire so that I can be ready when it comes time to replace it with a new range? Or would there be a disadvantage to converting my current range to use a 4-wire connection?

Thanks in advance,

Old 03-06-01, 05:21 PM
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There are some variables here. If your area has adopted the 1999 National Electrical Code, then the requirement is this: If you are installing a new cable from the breaker box to the outlet, you have to run a 4-wire cable, install a 4-wire receptacle, and use a 4-wire cord on the range. If you are not under the 1999 NEC, you do not have to go with the 4-wire setup.

If you are not running a new cable (if the old cable is existing) then leaving it a 3-wire set-up is ok.

You cannot change the outlet from a 3-wire to a 4-wire if the branch circuit is only 3-wire.

The difference is that in the past, the neutral of the branch circuit was allowed to be the ground for the range. Now, with the new code, this is not allowed, thus the additional wire, which is a grounding wire.

If you did run a 4-wire cable, and installed a 4-wire outlet, and now you want to use your old range, you will have to replace the cord to a 4-wire type. At the connection point on the back of the range, you will see three bolts(or screws), where the cord is connected, with a wire to each terminal. On the middle one, there will be a strap, wire or some kind of link, attaching that terminal to the chassis of the range. Remove this link, and attach the new grounding wire (green) to the chassis. The wiring diagram on the back of the range might give you the location of this point of grounding. The other terminals will wire the way that you took them off, that is the hots (could be both black, or 1 red and 1 black) will attach to the two outside terminals, and the neutral (white) will attach to the middle one.

PS. If you are buying a new range, make sure to purchase the cord that matches your setup.

Good luck.

Rick Miell
Old 03-06-01, 07:07 PM
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Couldn't have said it better if I tried. NO PIG WALLEREN ON THIS ONE. HA HA !

Old 03-07-01, 07:57 AM
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Thumbs up

Thanx for the info, Rick.

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