range and dryer neutral

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jetlag

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Eatonton, Georgia
I always thought the neutral on the 4 wire range and dryers only carried the 120 v circuit for the clock and timer. Thats why when it was 3 wire the code let that current go back in the GEC because it was a small current. Im seeing in the code now where the neutral carries the unbalanced load and the conductors are as large as the ungrounded conductors. How can that be ? Are they making the burner switches so they have 240 and 120 supply connected ? The reason Im asking is a lot of people who have a 3 wire rec will buy a 3 prong cord for a new stove. The stove comes with a jumper you can use to bond the neutral and ground. Ok this sends the neutral current into the # 10 EGC that comes in a 6/2 nm cu. I still dont believe the current from the burners goes in the neutral, if it does is this dangerous?
 
I believe that if you look at the exceptions that permit this sort of installation, you will find that the _ground_ wire in NM was never permitted to be used as the neutral.

The exceptions would permit an appropriately sized neutral conductor to serve as the 'EGC', but not the other way around. The closest that you get is the permission to use the concentric neutral of type SE cable, but 8/2 or 6/2 romex used in this application was and is a violation.

-Jon
 
winnie said:
I believe that if you look at the exceptions that permit this sort of installation, you will find that the _ground_ wire in NM was never permitted to be used as the neutral.

The exceptions would permit an appropriately sized neutral conductor to serve as the 'EGC', but not the other way around. The closest that you get is the permission to use the concentric neutral of type SE cable, but 8/2 or 6/2 romex used in this application was and is a violation.

-Jon
Click to expand...
You are correct that was SE cable they used back in the 3 wire days but now I find a lot of 8/2 nm ran for the ranges when I go to put in the 4 wire. But a lot of home owners install the jumper and put a 3 prong cord on the new range . Im still puzzled about if the elements are now 120 on low setting and 240 on high. I believe they are still only 240. Buy the way I called the elements burners above, Im sure some one will call me on it
 
Troubleshot a dryer last week.
Motor was 120V..... elements were 240......Loose "ground" on the NM.





Troubleshot a range in 1974.
High heat only.... Open "ground" on the SE.



Ground/neutral....whatever it takes.
 
jetlag said:
Thats why when it was 3 wire the code let that current go back in the GEC because it was a small current.
Click to expand...
No, this is a case of the neutral being permitted to also provide equipment grounding, not the other way around, not an EGC doing neutral duty.

The reason Im asking is a lot of people who have a 3 wire rec will buy a 3 prong cord for a new stove. The stove comes with a jumper you can use to bond the neutral and ground.
Click to expand...
The range (or dryer) should be fitted with whichever cordset matches the existing receptacle and circuit. A new installation always requires a 4-conductor supply, receptacle, and cordset.

Ok this sends the neutral current into the # 10 EGC that comes in a 6/2 nm cu.
Click to expand...
That is incorrect, and is probably related to why 2-conductor NM was never permitted. The options were either 3-conductor NM, using the insulated neutral, or using SE cable, where the bare conductor is a neutral.
 
jetlag said:
now I find a lot of 8/2 nm ran for the ranges when I go to put in the 4 wire.
Buy the way I called the elements burners above, Im sure some one will call me on it
Click to expand...

I can't imagine anyone running 8/2 NM to a range and thinking that it was OK.
Only if it was a unit with no 120V load, but I've never seen one....unless it was maybe a small apartment sized unit.

By the way.....I sometimes call the surface heating elements "burners", or "stove eyes".....usually "surface elements".

steve
 
thanks

thanks

220/221 said:
Troubleshot a dryer last week.
Motor was 120V..... elements were 240......Loose "ground" on the NM.





Troubleshot a range in 1974.
High heat only.... Open "ground" on the SE.



Ground/neutral....whatever it takes.
Click to expand...
Ok I think this answers my question, a range wont work on low heat without the neutral. Ive been wrong all these years because an instructor in license prep class in 92 told us the neut only carried current from clock and timer.
 
jetlag said:
Ok I think this answers my question, a range wont work on low heat without the neutral.
Click to expand...
You can't make such a blanket statement. Not all ranges are wired the same way.

For example, my parents had a GE cooktop with a row of seven or eight pushbuttons for each burner, which I believe were each made up of two elements, and each had four terminals.

The different heat settings switched the two elements in various combinations, with HI obviously placing them in parallel across 240v, and LO placing them in series across either 120v or 240v.

Other ranges have a continuously variable thermostat control, which has a heated bi-metallic strip inside the control, and the actual burner cycles with it as a slave load using 240v only.

The neutral usually carries only the light, timer, fan, etc., very much like a clothes dryer, where only the heating element connects to L2. That makes a dryer 120/240v and 120/208v compatible.
 
hillbilly said:
Only if it was a unit with no 120V load, but I've never seen one....

steve
Click to expand...

Never say never..:grin: I have installed a large wolf range that was 240 only. I have also wired a dryer that did not need a neutral. The 240 dryers have been more common than the ranges, in my experience
 
Dennis Alwon said:
Never say never..:grin: I have installed a large wolf range that was 240 only. I have also wired a dryer that did not need a neutral. The 240 dryers have been more common than the ranges, in my experience
Click to expand...

there is a lot of ranges that way. They use the bimetal strip to control the temp. There is no neutral connection to the element. I really think most were this way untill they came out with the 4 wire requirement.
 
I have always had issues with the dryer and the range with 3 wire..using the ground to complete a circuit makes it a functional ground and the NEC prohibits that..

earthing is protection = protective ground
using ground to carry current = functional ground
 
cschmid said:
I have always had issues with the dryer and the range with 3 wire..using the ground to complete a circuit makes it a functional ground and the NEC prohibits that..

earthing is protection = protective ground
using ground to carry current = functional ground
Click to expand...
Remember, the old allowance for the 3-wire circuit was for the neutral to also do the bonding chore, and not the other way around. The new rule adds an EGC, not a neutral.

When NM cable was used, the neutral always had to be insulated. In SE cable, the bare IS a neutral, just as with service entances.
 
jetlag said:
But a lot of home owners install the jumper and put a 3 prong cord on the new range.
Click to expand...
Actually, the jumper is already installed on most of these appliances at the factory. It's up to the installer to determine whether it should be removed or not. In the case of the homeowner, who in most cases is not as knowledgable as most of us are, they will usually take the easiest way out, not remove the jumper and use the 3-wire connection. In addition, if you purchase your appliance at one of the big box stores, they will usually tell you that the 3-wire connection is the appropriate way to go and, to make matters worse, there usually isn't enough or accurate information in the instruction manuals to point a novice in the right direction.

Take a good look at 250.140. There is an exception for existing branch circuit installations where ALL 4 conditions have to be met. Look particularly at condition # 3. If SE cable were used it had to have originated at the service equipment panel and not a sub-panel.
 
goldstar said:
If SE cable were used it had to have originated at the service equipment panel and not a sub-panel.
Click to expand...
That's why a bare conductor is allowed to be considered a neutral conductor. If a 3-wire SE cable is supplied from a sub-panel, where would you land the bare neutral, the neutral bus or the EGC bus?

The answer is that, if feed from a sub-panel, you're supposed to use a 4-wire circuit, even if it means replacing an existing circuit when a main panel is converted to being a sub-panel by a service upgrade.
 
Dennis Alwon said:
Never say never..:grin: I have installed a large wolf range that was 240 only. I have also wired a dryer that did not need a neutral. The 240 dryers have been more common than the ranges, in my experience
Click to expand...
Agreed. You never know what you've got until you take a look at the actual piece of equipment.
 
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