[jpbr]

I am replacing a wall oven. The new oven has 4 wires (black, white, red, bare). The wall has 3 wires (black, white, bare). The directions show how to wire to a 3 wire, but their diagram shows a black, white and red at the wall. I read that 240 doesn’t have a neutral. Is the white wire from the wall live as well as the black? If so, I am guessing black to black, red from oven to white at wall and white and bare from the oven to bare at the wall. Any help would be appreciated.
Thanks

 

[rjniles]

If you new oven has a white wire it is a 120/240 device not a 240 only device. There should be a label on the oven that confirms this.

I have bad news for you, you cannot use the existing wiring. The 3 wire method they describe requires 2 hots and an insulated neutral. You have 2 hots and a bare ground. The cable needs to be replaced with a 3 wire (plus bare ground) cable. The wire size depends on the amps the new oven requires.

 

[jpbr]

That is sad news. Thanks for the information.

 

[Fishbulb28]

Can you post a photo of the existing wiring or describe it in more detail? With certain cable types it may be acceptable to use the bare conductor as the neutral and ground.

 

[jpbr]

Thanks for the response. Here is a picture.

 

[Fishbulb28]

No, sorry. That isn't suitable. You'll need to run a new cable as rjniles said.

 

[seharper]

I'll confirm what fishbulb and rjniles say. This type of wiring is legal for a 240V-only oven, which may have been what came out. However, 240V-only ovens do not support common-as-dirt incandescent lights for oven lights (unless they include a transformer, which is unusual).

The only reason your new oven wants neutral is for the oven light and possibly controls. Either consult the manufacturer or get a different oven.

However, there are other serious problems with the workmanship in your photo.

- The cable is too short. It needs 6" of free length beyond the end of the sheath.
- The cable enters the junction box without a cable clamp on the sheath.
- The top knockout, well, the oven may use that.
- There is no physical protection for the cable.

Also watch your amps and wire size. Your cable smells like 12 AWG, which is too light for a 24A oven (but fine for a 16A oven). You'd be better off installing 10/3 cable, as that is more versatile and will support other ovens. Even better is 8/3 since that will support combo range/ovens.

 

[afjes2015]

jpbr: Besides the number of conductors needed to hook it up properly we should also be told what the electrical requirements are on this oven so we can advise the size of the conductors needed and the rating of the circuit breaker needed to hook it up safely and properly. Just running wires to have 120/240v is not the right way to go unless you know the other specs needed.



Can you post a brand and model number of the oven.