1

So I have an old range that I'll probably replace soon, so I decided to inspect the wiring box under the counter.

I wanted to make sure everything is safe when I wire the new range to the dedicated range 220V 4-wire (red, black, white, and bare Cu/ground) circuit. However, when I opened the junction box I noticed the following:

  • the range only has 3 wires: red,black, green.
  • the red wire nut splice looked burned, the plastic nut melted and was almost exposed
  • the neutral wire from the circuit was not connected at all any of the range's 3 wires
  • The range's green wire was connected to ground. This is wrong right?

I cut and cleaned the burned wire/nuts, and spliced it as such:

Here's a pic of after a bit of clean up.

So question: Is this wiring correct? I thought that in 3-wire ranges there's no ground, and the range's green wire was understood to be neutral..? And range's green should've been connected to the circuits white neutral?

What's the correct wiring here? range green => neutral OR range green => neutral+ground ? Thanks in advance.

UPDATE: So it's a very simple cooktop range (no oven), 4 coils, no digital clock, analog knob controls. The dedicated circuit powering it seems to be at least #10 gauge NM 3-wire + bare ground cable, and it's on a double 50A breaker.

UPDATE2: Here's the label for the cooktop: cooktop label

10
  • 2
    It appears that you have two different wire gauges there, places where the insulation is burned and burned through. All of those are RED FLAGS that your existing installation was inadequate. Chances are that your new range will need MORE power than the old one. Be sure your circuit is up to the task. It looks like it is not. – jwh20 Nov 29 '20 at 11:42
  • If your task right now is to make sure the existing range is connected properly then you may want to pull the panel on the back of the range and take a photo of how these wires are connected to the range. – Platinum Goose Nov 29 '20 at 13:55
  • 1
    @jwh20 -- it's normal for the appliance whip that comes with a hardwired appliance to use different size wire than the branch circuit feeding it as it operates under a different set of controlling rules. The burning is defintely a concern, but more than likely the result of bad splicing – ThreePhaseEel Nov 29 '20 at 14:46
  • How hard of a haul would it be to replace this circuit outright? It seems the prior installer cut some corners here... – ThreePhaseEel Nov 29 '20 at 14:47
  • @ThreePhaseEel I like the way the installer "screwed" the whip into the box ... lol – JACK Nov 29 '20 at 15:00
3

First the easy one:

The range's green wire was connected to ground. This is wrong right?

Actually, that is correct!

Now on with the show:

The usual correct wiring for a range is:

  • 2 x hot = typically black & red
  • 1 neutral = white
  • 1 ground = green or bare (or metal conduit)

In addition, the wires must be properly sized based on the current used by the range (big enough), and the breaker must be sized accordingly (small enough). For example, a 30A circuit will require at least 10 AWG wire (8 AWG is fine, 12 AWG is not) and a 30A breaker (smaller will result in nuisance trips, larger will not protect the wires from overheating).

You need to figure out what size wires and what size breaker you currently have. You may need to upsize one or (more likely) both to properly support the new range. Need to check with specifications of the new range.

There are certain situations - and you have at least one of these - where you only need 3 wires:

  • If the range only uses 240V and does not make use of 120V power at all, then it does not need or use a neutral, or have any connection for a neutral wire. That appears to be the case here. Most, but not all, newer ranges use 120V to power clock, timer, controls, etc.

  • If the range was installed a long time ago on a circuit that was installed a very long time ago, then a separate ground wire was not originally needed and ground and neutral combined was permitted at the time and is a grandfathered exception. In some places it is still a grandfathered exception. However, if upgrades to the wiring are needed (e.g., to change from 10 AWG to 8 AWG wire) then the exception goes away. This is not the case here, as you already have a 4-wire supply!

As far as the burn marks, etc. Those are serious problems. They could be due to undersized wires, but more likely due to loose connections. A loose connection can lead to arcing and burning and/or be high resistance which leads to overheating and burning. So cleaning up those connections is critical. I am extra concerned about the burning on the white (neutral) wire, which since it was not even connected should never overheat! Which indicates that there was likely some serious arcing going on that it burned the otherwise inert wire.

As noted, the range whip installation is not correct, and clearly there were other problems as well. Cleaning all of that up will help for now, but it may need to be all redone for the new range with new wires. I would certainly be concerned about the damage to that white wire since it will likely be needed for the new range.

You need to figure out what kind of wires you have (cable or individual wires, what size), what breaker you have, and what breaker/wire will be needed for the new range in order to decide exactly how to proceed with replacement.


Based on comments, updates, etc. This appears to be 8 AWG on a 50A double-breaker. Typically 8 AWG wire should have a 40A (or smaller) breaker. There are plenty of options that should work fine with that. I picked a GE 30" slide-in range with 4 burners and a self-cleaning oven at random from Home Depot, and the manual shows 240V @ 40A. So there is a good chance that if you swap the 50A breaker for a 40A breaker and clean up the wiring that you will be able to use this for a new range.

15
  • 1
    I'm pretty sure that's at least 8AWG NM the OP has there (10AWG NM would not have stranded wires in it), and by Code, that's good for any range up to about 13kW or so – ThreePhaseEel Nov 29 '20 at 16:17
  • 1
    @EdBeal -- the green in this case is coming from the old range's flex whip, there's a bare ground in the box as well that's coming from the branch circuit NM – ThreePhaseEel Nov 29 '20 at 18:14
  • 1
    @manassehkatz-Moving2Codidact so the burn on the white wire I think just comes from the way it was folded close to the bad red-wire splice. I'm 100% sure the neutral was just close to the splice and part of the insulation jacket got a bit charred. – unknownprotocol Nov 29 '20 at 21:57
  • 2
    @manassehkatz-Moving2Codidact the NM cable from the breaker to the range is 3-wire (red-black-white+bare ground)... I think this basement was finished in 2005 so it's not THAT old... – unknownprotocol Nov 29 '20 at 22:02
  • 2
    @manassehkatz-Moving2Codidact #8 copper should be on a 40A breaker. #6 can be on a 50A or possibly a 60A breaker. – Craig Nov 29 '20 at 22:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.