# 3 PRONG vs. 4 PRONG OVEN OUTLET?



## chris75

Casey_Oakland said:


> Hey all,
> 
> Looking for some info here, i recently had some work done in preperation of a kitchen remodel. The old wire for the oven was left untouched and the electrician assured me it was ok to use. He caped it with a three prong outlet but I've been reading up that the standard for modern oven is 4 prong!? Is this correct or will i have to open up the wall again? He seemed confident that this is fine.
> 
> Please advice, just want to make sure it's ok?
> 
> Much thanks!


With a few exceptions its legal... wanna know the exceptions?


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## Casey_Oakland

please... 

and what happens when i buy a new oven?
Do i have to outfit it with a diferent cord to fit the 3 prong?

Thanks!


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## chris75

Casey_Oakland said:


> please...
> 
> and what happens when i buy a new oven?
> Do i have to outfit it with a diferent cord to fit the 3 prong?
> 
> Thanks!


Ranges do not come with cords installed on them, so you just reuse your 3 wire cord. Stubbie has some great pics on the correct bonding procedure. 


Here are the exceptions...

*250.140 Frames of Ranges and Clothes Dryers*
Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes
dryers, and outlet or junction boxes that are part of the circuit for these appliances shall
be grounded in the manner specified by 250.134 or 250.138.
_Exception: For existing branch circuit installations only where an equipment grounding_
_conductor is not present in the outlet or junction box, the frames of electric ranges, wallmounted_
_ovens, counter-mounted cooking units, clothes dryers, and outlet or junction_
_boxes that are part of the circuit for these appliances shall be permitted to be grounded_
_to the grounded circuit conductor if all the following conditions are met._

_(1) The supply circuit is 120/240-volt, single-phase, 3-wire; or 208Y/120-volt derived_
_from a 3-phase, 4-wire, wye-connected system. _

_(2) The grounded conductor is not smaller than 10 AWG copper or 8 AWG aluminum._

_(3) The grounded conductor is insulated, or the grounded conductor is uninsulated and_
_part of a Type SE service-entrance cable and the branch circuit originates at the_
_service equipment._

_(4) Grounding contacts of receptacles furnished as part of the equipment are bonded to_​_the equipment._


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## Casey_Oakland

well...

That is a bit over my head but i feel reassured it is exceptable.
He did mention the ground wire and seemed very competent and confident it was safe.

I just want to make sure when I get the new stove I can successfully connect and it's ok to use.


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## chris75

Casey_Oakland said:


> well...
> 
> That is a bit over my head but i feel reassured it is exceptable.
> He did mention the ground wire and seemed very competent and confident it was safe.
> 
> I just want to make sure when I get the new stove I can successfully connect and it's ok to use.


 
As long as you had an electrican do the work, I would say you have a better than nothing that its correct.


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## Casey_Oakland

Relieved.. THANK YOU!


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## Stubbie

Hello Casey

Your new range will likely come configured for a three wire connection but you need to look carefully to be sure of this and carefully read your instructions as to the electrical requirements. You are allowed to reuse an *existing* 3 wire branch circuit under the conditions Chris posted.

Anyway the instructions will give you specific detail on how to convert the range and how it is configured from the factory...3 wire or 4 wire. If it is 3 wire configured you will simply need to purchase a 3 wire range cord connect it to your stove and plug it in. If it is 4 wire configured you will need to remove the bonding jumper from the neutral terminal on the range terminal block to the metal fram of the range. Manufacturers use different methods for this bonding jumper. Can be a metal strap, or a green and yellow striped wire etc. All this will be explained in the installation instructions. I'll post a few diagrams so you can get a feel as to what you will be looking for and this should help you understand the process.

First diagram is a 3 wire to 4 wire range connection

Second is a 3 wire connection usually how they come from the factory and will simply install a 3 wire range cord and plug into an existing 3 wire receptacle.


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## Casey_Oakland

Stubbie!
Huge help man!!!
Thank you so much!!!


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## Stubbie

Casey

I had the drawings reversed so I just changed the post to reflect the 3 wire is the second drawing.


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## Schrade

My problem is reversed there Mr. Stubbie...

My new range already has the 4-prong cord attached, and the outlet is 3-prong. I'm presuming I can pull the 3-prong cord from the old unit, and connect it to my new one...

BUT, which 'terminal' on the new stove is gonna' get left out? (or, do 2 of the terminals get bridged???)

EDIT:
Just found this elsewhere:


> The center terminal on the plug, indeed, needs to be connected to the white wire and the red and black wires to the side terminals. *You need to connect a ground wire preferably green from someplace on the stove to the grounding connection on the plug.* The stove will work just fine without it but if something goes wrong with the internal wiring of the stove, the chassis could become "hot" and the breaker wouldn't trip. Should that happen, you could get shocked with 120 V when you touch the range and something that is grounded at ...(Answered by dlmrgnk)


The grounding connection on the plug = neutral terminal on the 'range terminal block'?


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## theatretch85

fast1 said:


> wow you actually drew that?


Stubbie has a plethora of drawings and diagrams for just about anything. A lot of drawings and diagrams especially for sub panel setups and the many different requirements that go along with each setup configuration.


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## kbsparky

Casey_Oakland said:


> well...
> 
> That is a bit over my head but i feel reassured it is exceptable.
> *He did mention the ground wire* and seemed very competent and confident it was safe......


One note here: IF a "ground wire" is present, you have to use a 4-wire connection on the new appliance. The exception in the _Code _only applies if your ground wire is _not_ present.

Ask your electrician for clarification --- are there 3 or 4 conductors present in the junction box?


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## Casey_Oakland

old post but info still very much needed..

The cable itself has three wires and is rather old looking but functional..

Is that what you mean?

Not sure what it looks like in the junction box?


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## Schrade

Bumpin' here; post is gettin' buried already...



Schrade said:


> My problem is reversed there Mr. Stubbie...
> 
> My new range already has the 4-prong cord attached, and the outlet is 3-prong. I'm presuming I can pull the 3-prong cord from the old unit, and connect it to my new one...
> 
> BUT, which 'terminal' on the new stove is gonna' get left out? (or, do 2 of the terminals get bridged???)
> 
> EDIT:
> Just found this elsewhere:
> 
> 
> 
> The center terminal on the plug, indeed, needs to be connected to the white wire and the red and black wires to the side terminals. *You need to connect a ground wire preferably green from someplace on the stove to the grounding connection on the plug.* The stove will work just fine without it but if something goes wrong with the internal wiring of the stove, the chassis could become "hot" and the breaker wouldn't trip. Should that happen, you could get shocked with 120 V when you touch the range and something that is grounded at ...(Answered by dlmrgnk)
> 
> 
> 
> The grounding connection on the plug = neutral terminal on the 'range terminal block'?
Click to expand...


"old post ... AND, info still very..." :wink:


> old post but info still very much needed..


:whistling2: Your local grammar nazi @ work yup...


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## Schrade

> The grounding connection on the plug = neutral terminal on the 'range terminal block'?


Yup. :yes:


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## InPhase277

Sorry Schrade. You probably should have made a new post. Yours kinda got lost in the noise. The neutral terminal of the stove needs to be connected to the frame when you go to a 3-wire cord. How this is done is dependent on the brand of stove. Sometimes it is a wire that connects from the neutral terminal to a screw, and sometimes it is two wires connected together.


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## Schrade

InPhase277 said:


> Sorry Schrade. You probably should have made a new post. Yours kinda got lost in the noise. The neutral terminal of the stove needs to be connected to the frame when you go to a 3-wire cord. How this is done is dependent on the brand of stove. Sometimes it is a wire that connects from the neutral terminal to a screw, and sometimes it is two wires connected together.


Copy on that - thanks.

I fabbed a strap out of a corner brace, to bridge from the frame where the wire was attached, directly to the neutral terminal. She's toasty now! :yes:










If you're like me, be careful (I'm highly allergic to electricity - gives me the shakes 'n stuff. And I'll share too. Friends are good for keepin' ya' 'grounded - know what I mean?)


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