# Parallel Conductors



## backstay (Feb 3, 2011)

Found this today, I would say it is a violation of 310.10(H)(1) it's #8 wire and a 90 amp breaker.


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## McClary’s Electrical (Feb 21, 2009)

backstay said:


> Found this today, I would say it is a violation of 310.10(H)(1) it's #8 wire and a 90 amp breaker.


 

Yep, and those lugs aren't rated for two wires.


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## K2500 (Mar 21, 2009)

backstay said:


> Found this today, I would say it is a violation of 310.10(H)(1) it's #8 wire and a 90 amp breaker.


I'll have to take your word on the parallel conductors. I just see 2wires under the same lug. Also a violation, but 8's on a 90 may or may not be.


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## backstay (Feb 3, 2011)

K2500 said:


> I'll have to take your word on the parallel conductors. I just see 2wires under the same lug. Also a violation, but 8's on a 90 may or may not be.


It was marked as "welder" and had 4 #8's going to a 90 amp 2 pole QO breaker. Can't parallel under 1/0. This was in conduit, so the only thing I can think is they didn't have the right size wire and didn't want to come back to do it right.


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## BBQ (Nov 16, 2010)

backstay said:


> It was marked as "welder" and had 4 #8's going to a 90 amp 2 pole QO breaker. Can't parallel under 1/0. This was in conduit, so the only thing I can think is they didn't have the right size wire and didn't want to come back to do it right.


If it supplies two welder outlets it may be fine other than the two conductors under a lug.


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## backstay (Feb 3, 2011)

BBQ said:


> If it supplies two welder outlets it may be fine other than the two conductors under a lug.


I don't think a #8 copper is protected with a 90 amp breaker. It should be #3.


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## MF Dagger (Dec 24, 2007)

backstay said:


> I don't think a #8 copper is protected with a 90 amp breaker. It should be #3.


If it is a welder 90 might be fine. I don't have a book handy and don't do many welders.


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## BBQ (Nov 16, 2010)

MF Dagger said:


> If it is a welder 90 might be fine. I don't have a book handy and don't do many welders.


That is correct,it depends on the duty cycle of the welder.



> *630.12 Overcurrent Protection.
> 
> (B) For Conductors. *Conductors that supply one or more
> welders shall be protected by an overcurrent device rated or
> set at not more than 200 percent of the conductor ampacity.


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## K2500 (Mar 21, 2009)

backstay said:


> I don't think a #8 copper is protected with a 90 amp breaker. It should be #3.


Were it a motor than the breaker is serving for Short circuit and ground fault protection only. I forget the % for inverse time though.

Welders follow different rules as well.


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## user4818 (Jan 15, 2009)

BBQ is the Chuck Norris of the NEC. Don't mess with him.


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## MF Dagger (Dec 24, 2007)

Thanks BBQ, went to take a leak and found my 2011. Was just about to start looking.


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## MF Dagger (Dec 24, 2007)

Peter D said:


> BBQ is the Chuck Norris of the NEC. Don't mess with him.


I'd say more like the light skinned Danny Trejo.


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## BBQ (Nov 16, 2010)

K2500 said:


> Were it a motor than the breaker is serving for Short circuit and ground fault protection only. I forget the % for inverse time though.


I think 800%


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## BBQ (Nov 16, 2010)

MF Dagger said:


> I'd say more like the light skinned Danny Trejo.


Man, I did not know that name, I thought you misspelled Denny Terrio











And that would be embarrassing.


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## K2500 (Mar 21, 2009)

BBQ said:


> I think 800%


Thanks, that sounds right.
The only one I can ever remember off the top is 1100% for instantaneous. Not that I've ever used it.


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## MF Dagger (Dec 24, 2007)

BBQ said:


> Man, I did not know that name, I thought you misspelled Denny Terrio
> And that would be embarrassing.


No need for embarrassment.


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## BBQ (Nov 16, 2010)

K2500 said:


> Thanks, that sounds right.
> The only one I can ever remember off the top is 1100% for instantaneous. Not that I've ever used it.


Sorry I screwed up, 800 for instantaneous, like 250 or 300 for inverse.


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## K2500 (Mar 21, 2009)

BBQ said:


> Sorry I screwed up, 800 for instantaneous, like 250 or 300 for inverse.


Yep, just looked it up. What's the standard for energy efficient design B anyway, and why does it get 1100%.
Thats kinda counter intuitive.


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## RePhase277 (Feb 5, 2008)

Peter D said:


> BBQ is the Chuck Norris of the NEC. Don't mess with him.


You could be killed for saying that! Everybody knows that Chuck Norris is the Chuck Norris of the NEC:laughing:


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## Easy Al (Feb 28, 2011)

God said let there be light. Chuck Norris flipped the switch!


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## nitro71 (Sep 17, 2009)

Thing to take a look at besides the parrallel issue is what does it feed? Receptacle or disconnect? If it's a receptacle it would need to be rated at 90 amps. Course the conductor probably would act as a fuse....


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## jwjrw (Jan 14, 2010)

We rarely install SQD QO but I thought I was told QO breakers are rated for 2 wires. That is why they have 2 humps on their hold downs. I have no idea if that is correct.


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## Mike in Canada (Jun 27, 2010)

jwjrw said:


> We rarely install SQD QO but I thought I was told QO breakers are rated for 2 wires. That is why they have 2 humps on their hold downs. I have no idea if that is correct.


 You were told right. SQD QO breakers up to 30A can take one or two wires of copper or aluminum. Unless they're GFI or AFI... neither of these breaker types can take two wires.

Since the breaker in question is 90A, it's only rated for one wire, so in this case it's not kosher, but what you heard was basically correct.


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## Salvatoreg02 (Feb 26, 2011)

310.4(a) the entire design is a violation.

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## Dennis Alwon (May 9, 2009)

Salvatoreg02 said:


> 310.4(a) the entire design is a violation.
> 
> Sent from my iPhone using ET Forum


If it is truly a parallel installation it is non compliant based on 310.4 (2008) but if the 2 wires are going to separate welder outlets it may not be- Bob pointed this out in one of the beginning posts. The two #8's under the lug is definitely not compliant.


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## Salvatoreg02 (Feb 26, 2011)

Regardless, if it is a welder or not. It's still a violation.

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## BBQ (Nov 16, 2010)

Salvatoreg02 said:


> Regardless, if it is a welder or not. It's still a violation.


What part are you talking about?

Welders are odd, you could have a welder that was supplied with 8 AWG THHN protected by a 100 amp breaker and still be safe and code compliant.


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## Salvatoreg02 (Feb 26, 2011)

BBQ said:


> What part are you talking about?
> 
> Welders are odd, you could have a welder that was supplied with 8 AWG THHN protected by a 100 amp breaker and still be safe and code compliant.


The fact that there are two wires under one breaker. You can not parallel smaller then 1/0, unless one of the exceptions apply from 310.5

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## Dennis Alwon (May 9, 2009)

Salvatoreg02 said:


> The fact that there are two wires under one breaker. You can not parallel smaller then 1/0, unless one of the exceptions apply from 310.5
> 
> Sent from my iPhone using ET Forum


Sal- there can be two wires connected at one end and not connected at the other end-- that is not a parallel connection. I agree two wires under the breaker is an issue.


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## Salvatoreg02 (Feb 26, 2011)

Dennis Alwon said:


> Sal- there can be two wires connected at one end and not connected at the other end-- that is not a parallel connection. I agree two wires under the breaker is an issue.


Either way you can't use #8's for parallel conductors. As the op said they were in a conduit if they were by themselves or not I don't know. Its still a violation unless it's use is part of one of the exceptions 310.4

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## Big John (May 23, 2010)

Salvatoreg02 said:


> Either way you can't use #8's for parallel conductors....


 Unless I missed it, I think the sticking point is that without knowing where each of the four wires ends, we don't know if these _are _parallel conductors. They could be two separate circuits landed on the same breaker.

-John


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## Mike in Canada (Jun 27, 2010)

Big John said:


> Unless I missed it, I think the sticking point is that without knowing where each of the four wires ends, we don't know if these _are _parallel conductors. They could be two separate circuits landed on the same breaker.
> 
> -John


 Those lugs aren't rated for two conductors, so whether they're parallel or two circuits doesn't matter - it's still against code.


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## Salvatoreg02 (Feb 26, 2011)

Mike in Canada said:


> Those lugs aren't rated for two conductors, so whether they're parallel or two circuits doesn't matter - it's still against code.


I think we all agree that regardless of the how this circuit is being used there is more then one violation and there is nothing in the NEC that makes this installation compliant.

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