I have 2 old 220 runs where the cable has:

1 black
1 red
Outside wrapped bare

When I put the meter from either black or red to the outer wrapped wire I get 120v and between the black and the red I get 240v.

My new appliances say they work either 3 wire or 4 wire but I don't have that "white" (neutral)? Can I just tie the white and green to the bare cable? It appears that is how the old appliances where connected..?

Sounds like the wires may be old. I would replace the wire, adding a neutral, or run an additional white wire for a neutral.

Since the 3 wire cable is existing, you are allowed to use it for a range or a dryer. You can use a 3 wire cord and receptacle, however ,at the terminal strip inside where the cord connects you will find a jumper that must connect the metal frame of the appliance to the neutral wire, which is the bare wire wrapped around the two hot wires.

You cannot just install one wire to act as a neutral, as suggested, all the wires must be included in one cable or raceway.

If possible and practical, you may replace the 3 wire cable with one that has both a neutral and a ground, but not required. If you do use a 4 wire cable, then the jumper I mentioned earlier does not get connected.

Quote:

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Originally Posted by tkrussell

Since the 3 wire cable is existing, you are allowed to use it for a range or a dryer. You can use a 3 wire cord and receptacle, however ,at the terminal strip inside where the cord connects you will find a jumper that must connect the metal frame of the appliance to the neutral wire, which is the bare wire wrapped around the two hot wires.

You cannot just install one wire to act as a neutral, as suggested, all the wires must be included in one cable or raceway.

If possible and practical, you may replace the 3 wire cable with one that has both a neutral and a ground, but not required. If you do use a 4 wire cable, then the jumper I mentioned earlier does not get connected.

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Thanks for the follow up on this. The instructions don't mention a jumper and the wires already are inside of metal conduit coming out of the back of the oven and the microwave. Do I attempt to open the area around the cables on either unit?

The jumper I am referring to should be inside the appliance next to the terminal strip that the cord connects to.

Is this a new appliance that you need to install a cord on or an existing appliance with the cord alrady installed?

I need more clarity on the actual situation with the appliance.

Quote:

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Originally Posted by tkrussell

The jumper I am refering to should be inside the appliance next to the terminal strip that the cord connects to.

Is this a new appliance that you need to install a cord on or an existing appliance with the cord alrady installed?

I need more clarity on the actual situation with the appliance.

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It is a brand new GE Advantium Microwave and the cord with the metal flex conduit is already in place from the factory.

I went out and looked in my main panel. It appears that the wire that is wrapped (bare) around the black and red wires is tied to the Netural block side.

So I would take this to mean that the white from the appliance would go to the bare wrapped wire but what about the green ground? To the wrapped as well?

Ok all you need to do is splice all the wires in a 4 & 11 box
(4-11/16ths x 4-11/16ths inch square),color for color, and the bare, the white, and any green wires all splice together.

Be sure to use a large wire connector to insure a very good connection to all these wires. Use the best and simplest wire connector you can to make the splices good and tight.

If the home is ever renovated, then the 3 wire cable needs to be replaced with one with a separate ground, otherwise your installation is safe until then, just the code gets a bit more technical and strigent as it evolves.

Be sure to install a box cover.

Glad to hear you traced it and found a neutral.:)

Quote:

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Originally Posted by tkrussell

Ok all you need to do is splice all the wires in a 4 & 11 box
(4-11/16ths x 4-11/16ths inch square),color for color, and the bare, the white, and any green wires all splice together.

Be sure to use a large wire connector to insure a very good connection to all these wires. Use the best and simplest wire connector you can to make the splices good and tight.

If the home is ever renovated, then the 3 wire cable needs to be replaced with one with a separate ground, otherwise your installation is safe until then, just the code gets a bit more technical and strigent as it evolves.

Be sure to install a box cover.

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Excellent. I will take some good pictures to share with others who may have this issue in the future. Again, thanks...

BTW. When we just took the microwave out of the box, they had the green and white already joined together with a metal holder - NICE, considering the instructions were vague in the first place.