# Electric Dryer wiring???



## sparks134 (Jan 30, 2009)

I went on a residential service call today and came across this: 

A 220V, 30A dryer wired with #6 Aluminum on a 50A breaker, now I knew the wire size was correct for the 50A breaker, but knowing that this was on a plug rated for 30A I went ahead and changed it out to a 30A breaker at the main...

Was this correct for me changing this breaker out?


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## jwjrw (Jan 14, 2010)

Yea you did what I would of done. I've never seen a resi dryer take more than a 30.


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## sparks134 (Jan 30, 2009)

Thanks...this really had me thinking...better safe than sorry, right!:thumbsup:


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## B4T (Feb 10, 2009)

Yes... I have done that a few times when guys ran #8 for dryer outlet

This was 8/3 plain.. no ground.. many dryers that shared neutral and ground off insulated neutral


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## 480sparky (Sep 20, 2007)

Probably some wanna-be electrician saw the #6, and automatically stuck in a 50a breaker.


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## jbfan (Jan 22, 2007)

Maybe at one time fed a stove!
You did the right thing.


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## RIVETER (Sep 26, 2009)

What you did does not hurt but usually the breaker is there to protect the conductors, not the appliance.


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## nitro71 (Sep 17, 2009)

You did the right thing. Can't have the circuit fused for more than that outlet is rated at when you have one outlet.


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## zen (Jun 15, 2009)

does that apply to 15 amp outlets on a 20 amp circuts?


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## raider1 (Jan 22, 2007)

zen said:


> does that apply to 15 amp outlets on a 20 amp circuts?


If it is a single receptacle on a 20 amp circuit it must be a 20 amp receptacle. (See 210.21(B)(1))

If you have a duplex receptacle or multiple receptacles on a a 20 amp circuit then you can install eiter 15 or 20 amp receptacles. (See 210.21(B)(3))

Chris


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## jw0445 (Oct 9, 2009)

zen said:


> does that apply to 15 amp outlets on a 20 amp circuts?


15A duplex receptacles are rated to pass through 20A.


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## DHC (Jan 29, 2009)

Believe it or not, a friend of mine had his rough in inspection red tagged for that same type of install. He had quite a bit of 6/3g left over so instead of going to the supply house to get 10/3g for the dryer outlet he used the 6/3g with a 2P 30A breaker. The inspector failed it, he asked my opinion and I told him to challenge it because NEC had no requirements prohibiting it. He did and it was over turned but still made him look bad in front of the customer.


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## 480sparky (Sep 20, 2007)

DHC said:


> Believe it or not, a friend of mine had his rough in inspection red tagged for that same type of install. He had quite a bit of 6/3g left over so instead of going to the supply house to get 10/3g for the dryer outlet he used the 6/3g with a 2P 30A breaker. The inspector failed it, he asked my opinion and I told him to challenge it because NEC had no requirements prohibiting it. He did and it was over turned but still made him look bad in front of the customer.


Ah yes, yet another inspector that needs 'education'.


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## jwjrw (Jan 14, 2010)

DHC said:


> Believe it or not, a friend of mine had his rough in inspection red tagged for that same type of install. He had quite a bit of 6/3g left over so instead of going to the supply house to get 10/3g for the dryer outlet he used the 6/3g with a 2P 30A breaker. The inspector failed it, he asked my opinion and I told him to challenge it because NEC had no requirements prohibiting it. He did and it was over turned but still made him look bad in front of the customer.


 

I would of laughed at that inspector and asked for a code reference. You can pull any larger size wire you want and fuse it to the appliance. Show me Mr Inspector where I am wrong.....


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## 480sparky (Sep 20, 2007)

jwjrw said:


> I would of laughed at that inspector and asked for a code reference. You can pull any larger size wire you want and fuse it to the appliance. Show me Mr Inspector where I am wrong.....


It's perfectly legal to install 2,000 kcmil copper and protect it with a 15a fuse/breaker. Every inspector should know that.

Using larger wire for voltage drop is very common, especially in commercial. Yet for some reason, there's still inspectors out there who don't understand that it's legal in residential as well.

Not arguing with you, jw, just commenting.


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## DHC (Jan 29, 2009)

Laugh is exactly what I did when he told me. He said the inspector claimed it wasn't UL listed for the breaker to terminate wire that large and I laughed even harder. So, he took the same style breaker to the powers that be and they told the inspector not to over interperet the code. 
Point Sparkies! Score, sparkies 1; local AHJ 0.:thumbup:


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## 480sparky (Sep 20, 2007)

DHC said:


> Laugh is exactly what I did when he told me. He said the inspector claimed it wasn't UL listed for the breaker to terminate wire that large and I laughed even harder. So, he took the same style breaker to the powers that be and they told the inspector not to over interperet the code.
> Point Sparkies! Score, sparkies 1; local AHJ 0.:thumbup:



Well, there will be a limit to the largest wire a breaker can legally terminate. Obviously, you won't ever get a 2,000 kcmil to land on a 15 amp breaker.


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## Split Bolt (Aug 30, 2010)

480sparky said:


> Well, there will be a limit to the largest wire a breaker can legally terminate. Obviously, you won't ever get a 2,000 kcmil to land on a 15 amp breaker.


Yeah, you'd have to trim quite a few strands!:thumbup:


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## 480sparky (Sep 20, 2007)

Split Bolt said:


> Yeah, you'd have to trim quite a few strands!:thumbup:


As well as make sure it's bent perfect. Otherwise, it'll pull the breaker right off the bus bar. :shifty:


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## jwjrw (Jan 14, 2010)

DHC said:


> Laugh is exactly what I did when he told me. He said the inspector claimed it wasn't UL listed for the breaker to terminate wire that large and I laughed even harder. So, he took the same style breaker to the powers that be and they told the inspector not to over interperet the code.
> Point Sparkies! Score, sparkies 1; local AHJ 0.:thumbup:


 

They make crimp on tits to go into the breaker that are ul listed for that purpose. What an idiot.:yes:
I pulled 300mcm and had to use them on a 225 amp breaker.


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## raider1 (Jan 22, 2007)

DHC said:


> Believe it or not, a friend of mine had his rough in inspection red tagged for that same type of install. He had quite a bit of 6/3g left over so instead of going to the supply house to get 10/3g for the dryer outlet he used the 6/3g with a 2P 30A breaker. The inspector failed it, he asked my opinion and I told him to challenge it because NEC had no requirements prohibiting it. He did and it was over turned but still made him look bad in front of the customer.


250.122(B) would make installing 6/3 NM cable on a 30 amp circuit breaker a violation.

The EGC in a 6/3 NM cable is a #10 and 250.122 requires that if the ungrounded conductors of a circuit are up sized then the EGC must be proportionally increased in size.

So for a 30 amp circuit breaker the EGC would need to be the same size as the ungrounded conductors.

This may be a nit picky violation but a violation all the same.

Chris


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## jwjrw (Jan 14, 2010)

raider1 said:


> 250.122(B) would make installing 6/3 NM cable on a 30 amp circuit breaker a violation.
> 
> The EGC in a 6/3 NM cable is a #10 and 250.122 requires that if the ungrounded conductors of a circuit are up sized then the EGC must be proportionally increased in size.
> 
> ...


 
Sad thing is his inspector failed him for something else. Failed him because the wire does not fit in the breaker. Had he said romex that might of clicked in my mind. Raider on the scene once again.


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## raider1 (Jan 22, 2007)

jwjrw said:


> Sad thing is his inspector failed him for something else. Failed him because the wire does not fit in the breaker. Had he said romex that might of clicked in my mind. Raider on the scene once again.


I agree, the inspectors call on the listing of the breaker was incorrect.

Chris


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## 480sparky (Sep 20, 2007)

raider1 said:


> 250.122(B) would make installing 6/3 NM cable on a 30 amp circuit breaker a violation.
> 
> The EGC in a 6/3 NM cable is a #10 and 250.122 requires that if the ungrounded conductors of a circuit are up sized then the EGC must be proportionally increased in size.
> 
> ...



Good catch! :thumbsup:


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## raider1 (Jan 22, 2007)

480sparky said:


> Good catch! :thumbsup:


Thanks.

Chris


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## DHC (Jan 29, 2009)

Good one Raider! :notworthy:


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## nitro71 (Sep 17, 2009)

raider1 said:


> 250.122(B) would make installing 6/3 NM cable on a 30 amp circuit breaker a violation.
> 
> The EGC in a 6/3 NM cable is a #10 and 250.122 requires that if the ungrounded conductors of a circuit are up sized then the EGC must be proportionally increased in size.
> 
> ...


I think that code section is poorly written. I "believe" the intent is that someone doesn't put in larger fused conductors with a smaller ground on a smaller breaker then in the future someone fuses the circuit with a larger breaker but doesn't pull a new ground. I pull in a ground that is sized based off the largest breaker that could be used on that circuit. I'm not going to upsize my grounds past that point.


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## zen (Jun 15, 2009)

if im understanding this correctly,,the breaker size cant be smaller than the ground size,,like a 6/2 for an a/c unit would have to have atleast a 30a breaker but not more than a 50a ,,,,,,,,,,i havent had this problem i think,, because on our inspections we have to size according to name plate ratings,,,for all equipment which usually means the wire is correct for the breaker size.,,,,im thinking in nm cable the ground is sized accordingly for the ungrounded and breaker size


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## 480sparky (Sep 20, 2007)

zen said:


> if im understanding this correctly,,the breaker size cant be smaller than the ground size,,like a 6/2 for an a/c unit would have to have atleast a 30a breaker but not more than a 50a ,,,,,,,,,,i havent had this problem i think,, because on our inspections we have to size according to name plate ratings,,,for all equipment which usually means the wire is correct for the breaker size.



The breaker is not sized to the grounding conductor, but the other way around.

The confusion is created when getting into ungrounded conductors larger than #10. 

Let's say I'm wiring a load that requires #6 on a 50a breaker. I install #6, but 250-122 says I only need a #10 ground, so I install a #10 ground. All perfectly legal.

However, let's say I have a load that only requires #10 on a 30a breaker. I still need a #10 ground, according to 250-122, right? Now let's say that, due to excessive circuit length, I want to increase my wire size to #6. I still use a 30a breaker, but according to 250.122(B), when I increase the ungrounded conductors, I must also increase the grounding conductor. So I need a #6 ground when the circuit is on a 30a breaker.


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## zen (Jun 15, 2009)

thanks 480 i understand now.....i can remember running larger wire for voltage drop but we didnt upsize the ground.....we didnt get a red tage but its still good info to know


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## 480sparky (Sep 20, 2007)

zen said:


> thanks 480 i understand now.....i can remember running larger wire for voltage drop but we didnt upsize the ground.....we didnt get a red tage but its still good info to know



It seems like a bizarre rule when applied to voltage drop, but the ground needs to have a low enough impedence to allow enough current to flow in order for the OCD to operate properly. Too small a ground when there's a short circuit, and things can get ugly inside of a few seconds.


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## Split Bolt (Aug 30, 2010)

Zen, is that a Dean "Z" you are playing?


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## Shockdoc (Mar 4, 2010)

DHC said:


> Laugh is exactly what I did when he told me. He said the inspector claimed it wasn't UL listed for the breaker to terminate wire that large and I laughed even harder. So, he took the same style breaker to the powers that be and they told the inspector not to over interperet the code.
> Point Sparkies! Score, sparkies 1; local AHJ 0.:thumbup:


 I've done that a few times on kitchen remods, using the 10/3 as 20 amp circuits or the 8/3 for 20 amp circuits. I just pigtail them down in the panel to the guage wire there getting fused at to keep wanna bes from placing larger breakers on them later. Must have been one of those all in one inspectors that are jack asses whop failed your friend.


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## zen (Jun 15, 2009)

Split Bolt said:


> Zen, is that a Dean "Z" you are playing?


 why yes it is,,,it doesnt belong to me i have a buddy that collects them since daryl passed away...


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## raider1 (Jan 22, 2007)

Shockdoc said:


> I've done that a few times on kitchen remods, using the 10/3 as 20 amp circuits or the* 8/3 for 20 amp circuits*. I just pigtail them down in the panel to the guage wire there getting fused at to keep wanna bes from placing larger breakers on them later. Must have been one of those all in one inspectors that are jack asses whop failed your friend.


Check post 21, 8/3 NM cable on a 20 amp circuit breaker is a violation of 250.122(B). The EGC in the 8/3 would need to be a #8 to comply with that section.

Chris


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## frenchelectrican (Mar 15, 2007)

raider1 said:


> Check post 21, 8/3 NM cable on a 20 amp circuit breaker is a violation of 250.122(B). The EGC in the 8/3 would need to be a #8 to comply with that section.
> 
> Chris


 
That one reason why I refuse to use the NM on very long runs the EGC will get ya and I learn that in France so it the same way in USA so no diffrence on that.

If I have to make a very long run by upsizing I just go with THHN conductors ( with correct EGC size ) with conduit and be done with it.

Merci.
Marc


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## Shockdoc (Mar 4, 2010)

raider1 said:


> Check post 21, 8/3 NM cable on a 20 amp circuit breaker is a violation of 250.122(B). The EGC in the 8/3 would need to be a #8 to comply with that section.
> 
> Chris


Most almost every remod that needs new circuitry was wired in the 60's thru early 90's where the 8/3 came ungrounded in which the red conductor is reindentified as a grounding conductor and the cable is used as 1 circuit. But in this day and age there is code and then there is reality and some rules should be followed only by those who made them.


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