# commercial piping



## may electric (Aug 17, 2010)

I am moving from residental to commercial work and had a quick question.

If I pull 3 current carrying conductors (black, red, blue) in one pipe can I run one neutral conductor and still put them on 3 single pole breakers or do i need to have a 3 pole breaker. And where in the NEC talk about this.


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## oldtimer (Jun 10, 2010)

may electric said:


> I am moving from residental to commercial work and had a quick question.
> 
> If I pull 3 current carrying conductors (black, red, blue) in one pipe can I run one neutral conductor and still put them on 3 single pole breakers or do i need to have a 3 pole breaker. And where in the NEC talk about this.


 Is the circuit 3 phase, or 3 single phase. NEED MORE INFO....


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## may electric (Aug 17, 2010)

Yes it is 3 phase 120/208 panel


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## oldtimer (Jun 10, 2010)

may electric said:


> Yes it is 3 phase 120/208 panel


 That is what I was asking, are they 3 single circuits, or 1, 3 phase circuit ?


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## mattsilkwood (Sep 21, 2008)

Look at 210.4 (2008).


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## jwjrw (Jan 14, 2010)

In 2008 all muilt wire circuits have to use handle ties or a multi pole breaker.


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## nitro71 (Sep 17, 2009)

No different than residential in this respect. Same code. Have to have handle ties on the breakers if you are sharing a neutral.


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## Brandon H (Aug 16, 2010)

to my understanding one neutral can have a maximum of two circuits on it.


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## jwjrw (Jan 14, 2010)

Brandon H said:


> to my understanding one neutral can have a maximum of two circuits on it.


Nope we do 3 usually on 3 phase.


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## crazyboy (Nov 8, 2008)

Brandon H said:


> to my understanding one neutral can have a maximum of two circuits on it.


What about super neutrals?


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## Frasbee (Apr 7, 2008)

crazyboy said:


> What about super neutrals?


Super neutrals?

What is that, an oversized neutral?

To my knowledge 3 is the max, regardless. At least, that's what I've been told.


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## Brandon H (Aug 16, 2010)

Frasbee said:


> Super neutrals?
> 
> What is that, an oversized neutral?
> 
> To my knowledge 3 is the max, regardless. At least, that's what I've been told.


I'm with you on the super neutrals


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## 480sparky (Sep 20, 2007)

Frasbee said:


> ..............To my knowledge 3 is the max, regardless. At least, that's what I've been told.



As the Code is currently written, you can have _every circuit in the panel_ on _one _neutral, provided it is sized accordingly.

That's gonna change in the '11, so I heard.


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## slickvic277 (Feb 5, 2009)

480sparky said:


> *As the Code is currently written, you can have every circuit in the panel on one neutral, provided it is sized accordingly.
> *
> That's gonna change in the '11, so I heard.




I guess every breaker in the panel would have to be connected b a handle tie then too?


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## slickvic277 (Feb 5, 2009)

Super neutrals are a gimmick put together by cable companies to compensate for harmonics on non-linear loads. Well in my opinion it's a gimmick.


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## Bob Badger (Apr 19, 2009)

slickvic277 said:


> Super neutrals are a gimmick put together by cable companies to compensate for harmonics on non-linear loads. Well in my opinion it's a gimmick.


I think that is pretty accurate.

If you had a 3 phase multiwire branch circuit heavily loaded with non-linear loads it is possible for the neutral to be overloaded. 

However most EEs design circuits supplying non-linear loads with very light loading.


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## RIVETER (Sep 26, 2009)

Bob Badger said:


> I think that is pretty accurate.
> 
> If you had a 3 phase multiwire branch circuit heavily loaded with non-linear loads it is possible for the neutral to be overloaded.
> 
> However most EEs design circuits supplying non-linear loads with very light loading.


Are you kidding me? Are there really cable manufacturers out there advertising about super neutrals. How does a harmonic know to only stay on the white wire?


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## Bob Badger (Apr 19, 2009)

RIVETER said:


> Are you kidding me? Are there really cable manufacturers out there advertising about super neutrals.


Yes and miles of it are installed, along with double neutral condutor feeders. (3 hots, 2 Neut. 1 Gnd.



> How does a harmonic know to only stay on the white wire?


I wish I could explain it but I really can't.

With a three phase Wye system the harmonic currents do not cancel each other out, they start to add up on the neutral.

An engineer explained to me that _theoretically_ you could have 1.73 times the current of any single phase conductor on the neutral.


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## Shockdoc (Mar 4, 2010)

slickvic277 said:


> Super neutrals are a gimmick put together by cable companies to compensate for harmonics on non-linear loads. Well in my opinion it's a gimmick.


Super neutrals can come in the configuiration of one #8 to six #12 circuits on a three phase system. I guess shoving a nail as a handle tie would satisfy the corporate lords with the 08 code change.


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## 480sparky (Sep 20, 2007)

RIVETER said:


> Are you kidding me? Are there really cable manufacturers out there advertising about super neutrals. .........



Absotively posilutely.

Allied.
AFC.
Kaf-Tech.


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## brian john (Mar 11, 2007)

Triplen harmonics are additive in the neutral conductors on multiwire circuits with, if the maximum load is achieved on each conductor it is possible to overload the neutral conductor.

But in my experience few (very few) branch circuits are loaded to their max in installations utilizing high amounts of triplen harmonics.

http://ecmweb.com/mag/electric_trouble_comes_threes/


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## bobelectric (Feb 24, 2007)

Multi-wire circuits sharing a common neutral are a future problem waiting to happen.Look at having to install a gfi or an afci on an existing circuit.​


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## jwjrw (Jan 14, 2010)

bobelectric said:


> Multi-wire circuits sharing a common neutral are a future problem waiting to happen.Look at having to install a gfi or an afci on an existing circuit.​


 

Bob have you been drinking this morning already??????
A mulit wire circuit means you share a neutral.....and the only problem with them is the idiots that don't know what one is......
Gfi or arc????:blink:


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## may electric (Aug 17, 2010)

I just ment if I have a pipe and I pull 6 current carry wire for 6 single curcuits how many nutrals would I need to pull


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## Southeast Power (Jan 18, 2009)

brian john said:


> Triplen harmonics are additive in the neutral conductors on multiwire circuits with, if the maximum load is achieved on each conductor it is possible to overload the neutral conductor.
> 
> But in my experience few (very few) branch circuits are loaded to their max in installations utilizing high amounts of triplen harmonics.


OK but lets keep this theory focused on WYE systems where it belongs.


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## knowshorts (Jan 9, 2009)

may electric said:


> I just ment if I have a pipe and I pull 6 current carry wire for 6 single curcuits how many nutrals would I need to pull


ABCN, ABCN. Handle ties or 3 phase breakers required on '08 cycle.


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## brian john (Mar 11, 2007)

jrannis said:


> OK but lets keep this theory focused on WYE systems where it belongs.


 
Wye systems are the one where triplens harmonics are the POSSIBEL issue.

In single phase 240/120 VAC systems triplens are not an issue.


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## 480sparky (Sep 20, 2007)

bobelectric said:


> Multi-wire circuits sharing a common neutral are a future problem waiting to happen.Look at having to install a gfi or an afci on an existing circuit.​



Perhaps you can put down your drink, get out your crystal ball and let the rest of us in on how to 'future-proof' the work we're doing today.


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## 480sparky (Sep 20, 2007)

may electric said:


> I just ment if I have a pipe and I pull 6 current carry wire for 6 single curcuits how many nutrals would I need to pull



No single answer to this. If any of the circuits are on either AFCI or GFCI breakers, you'll need a separate noodle for those.

Also, just because there's 6 circuits doesn't automatically mean they're grouped in the panel. You could be pulling circuits #2, 9, 17, 18, 37 and 42.


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## oldtimer (Jun 10, 2010)

480sparky said:


> Perhaps you can put down your drink, get out your crystal ball and let the rest of us in on how to 'future-proof' the work we're doing today.


 W T F is Futureproof? :001_huh:

E C s will have to hire profilers, to analyse H O s. Wow!! :jester:


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## 480sparky (Sep 20, 2007)

oldtimer said:


> W T F is Futureproof? :001_huh:
> 
> E C s will have hire profilers, to analyse H O s. Wow!! :jester:



_Future-proof _means installing today's technology so it will be compatible with whatever is invented some time in the future.


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## Southeast Power (Jan 18, 2009)

Maybe we will have Arc-Fault Receptacles (plugs for some of you guys) in the future.


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## Rudeboy (Oct 6, 2009)

I think afci receptacles exist already. Never installed one but...


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## oldtimer (Jun 10, 2010)

Rudeboy said:


> I think afci receptacles exist already. Never installed one but...


WHAT???:blink:


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## Rudeboy (Oct 6, 2009)

oldtimer said:


> WHAT???:blink:


I might be wrong. I did a quick search and didn't find anything but for some reason I remember seeing a product before.
Must have seen it here:
http://www.electriciantalk.com/f2/afci-receptacles-2249/
Damn that website!


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## oldtimer (Jun 10, 2010)

Rudeboy said:


> I might be wrong. I did a quick search and didn't find anything but for some reason I remember seeing a product before.
> Must have seen it here:
> http://www.electriciantalk.com/f2/afci-receptacles-2249/
> Damn that website!


 Are you serious? You must be joking!! You have never seen A F C I s ??? 


SURELY YOU JEST.:jester:


P.S. I wont call you Shirley.


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## Rudeboy (Oct 6, 2009)

oldtimer said:


> Are you serious? You must be joking!! You have never seen A F C I s ???
> 
> 
> SURELY YOU JEST.:jester:
> ...


I was talking about AFCI Receptacles that I've never seen.:laughing:

I _have_ seen an AFCI breaker or two. :jester:

Ever seen a grown man naked?


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## oldtimer (Jun 10, 2010)

Rudeboy said:


> I was talking about AFCI Receptacles that I've never seen.:laughing:
> 
> I _have_ seen an AFCI breaker or two. :jester:
> 
> Ever seen a grown man naked?


 I guess you are right. I have heard of them, but I have not seen them either.

I googled Leviton, and Hubbell, and they say; Coming Soon.

Sorry, I misunderstood your post.


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## slickvic277 (Feb 5, 2009)

Bob Badger said:


> I think that is pretty accurate.
> 
> If you had a 3 phase multiwire branch circuit heavily loaded with non-linear loads it is possible for the neutral to be overloaded.
> 
> However most EEs design circuits supplying non-linear loads with very light loading.



Yeah, I agree with the design but sometimes things that the EE's due make me scratch my head.

On an office fit-out I was on all the receptacle circuits that fed the desktop computers were fed with MC that contained the super "N". But here's the thing, it was only 5 desks per circuit. How much of a harmonic load could 5 computers introduce? Enough to cause real problems? I doubt it.

I wonder if this EE had a deal with the cable manufacturer.


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## jwjrw (Jan 14, 2010)

slickvic277 said:


> Yeah, I agree with the design but sometimes things that the EE's due make me scratch my head.
> 
> On an office fit-out I was on all the receptacle circuits that fed the desktop computers were fed with MC that contained the super "N". But here's the thing, it was only 5 desks per circuit. How much of a harmonic load could 5 computers introduce? Enough to cause real problems? I doubt it.
> 
> I wonder if this EE had a deal with the cable manufacturer.


 
Probably the same deal someone in the union had with the contractor......:laughing:


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## slickvic277 (Feb 5, 2009)

jwjrw said:


> Probably the same deal someone in the union had with the contractor......:laughing:


:whistling2:


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## voltz (Jun 2, 2010)

jrannis said:


> Maybe we will have Arc-Fault Receptacles (plugs for some of you guys) in the future.


(outlets for others)


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