How do you install a stove top when it comes with black white green and red wires and the junction box only has black red and green?

Answer 1

First, find a volt meter and test the junction box. Determine if it's 120 VAC or 240 VAC.

If your new stove top requires 240VAC, you had better make certain that the junction box has the same voltage.

IF the power at the junction box is 240 VAC, AND the stove top requires 240 VAC, simply connect black to black, white to red and green to green.

If ANYTHING does not seem right (I.E. voltages don't match), contact a local electrician or qualified handyman (if handymen are allowed in your state)

I most older homes the 220 was installed with three wires, usually red, black and white or black white and bare. newer homes have a four wire system: red, black white and bare. In the case where there are three wires in the junction box and four on the cooktop, oven, etc. you would simply connect the white and green from the appliance together and connect them to the neutral in the junction box.

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I must object to the idea of tying the white and green from the appliance together and connecting them to the neutral (or green, from your description) in the junction box. There is no doubt this will allow the appliance to work properly under most circumstances. However, it makes the metal parts of your cook top, the parts that are not supposed to be electrical, to be potential current carrying conductors. If you touch the cook top and provide a better ground than the one already provided you can get shocked or worse. Do not do this. See my suggestion on the discussion page. --- Sparkfighter

I respect your position on this and in a perfect world your way would be the best way. I have installed well over 3000 electric appliances over the last ten years. (Kitchen Aid, Whirlpool, GE, Monogram, Bosch, Thermador, Wolf, SubZero, Miele, Gaggenaux, Liebherr, Viking to name a few). I have actually driven or been flown to classes for particular appliances and am a certified installer. In most cases the appliance (ovens and cooktops) actually come with the neutral and ground tied together. In the case where you have four wires the installation instructionstell you to separate them. In the case where they they come separate you are required to tie them together. Dryers and ranges do not come with a cord. so if you have a three wire system you connect a (supplied) bond bar between the neutral and the ground in the appliance. The only time that it was not suggested we not do this was when Miele first started selling appliances in the states. They wanted us to have an isolated ground. This prevented me from installing their appliances in many homes. They have since dropped this requirement. I never understood their position on this as in houses built before 1986 or so, the neutral and ground were connected to the same bar in the electrical panel. (I think that mobile homes are still not required to have four wires for a 220). How did the electricity know the difference between neutral and ground? They are technically the same thing. Even if you could run an additional wire to the panel (in many or most cases) you would be hooking the wire up to the same bar. I think that it was a good idea that the national electrical code made that change to have separate bars as having a true ground is of the utmost importance.

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You are right that with all else being proper, the electricity doesn't know the difference. But the ground is there to ensure the proper operation of the over current device (breaker) in case of a fault. It carries current only when there is a fault and only momentarily. The neutral carries current any time the circuit is in use. Well, when there is an unbalanced load, in this case. The ground connects all the non-electrical metal parts together so to tie the neutral and ground together makes any metal part a potential hazard. I'm not disagreeing with you that your method would work. I'm saying it creates a potential hazard that ought to be avoided. I might do this in my own home because I can be certain the ground is right. But I would not advise an amateur to do this.