# Current Carrying Conductor...



## bengie

When is a neutral considered a CCC ???


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## 480sparky

bengie said:


> When is a neutral considered a CCC ???





> *310.15(B)(4) Neutral Conductor. *
> (a) A neutral conductor that carries only the unbalanced current from other conductors of the same circuit shall not be required to be counted when applying the provisions of 310.15(B)(2)(a).
> (b) In a 3-wire circuit consisting of two phase conductors and the neutral conductor of a 4-wire, 3-phase, wye-connected system, a common conductor carries approximately the same current as the line-to-neutral load currents of the other conductors and shall be counted when applying the provisions of 310.15(B)(2)(a).
> (c) On a 4-wire, 3-phase wye circuit where the major portion of the load consists of nonlinear loads, harmonic currents are present in the neutral conductor; the neutral conductor shall therefore be considered a current-carrying conductor.


Clear as mud, right?


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## bengie

I know where that is in the NEC but it must be in another language... I 

dont really understand????


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## RIVETER

bengie said:


> I know where that is in the NEC but it must be in another language... I
> 
> dont really understand????


 I answered the wrong post. Sorry.


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## bengie

So in a single phase 2 hots and 1 nuetral, we dont cont it as CCC, but 

when we have 1 hot and 1 nuetral its is counted. Does thats sound right? 

Still learning everyday!


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## RIVETER

bengie said:


> So in a single phase 2 hots and 1 nuetral, we dont cont it as CCC, but
> 
> when we have 1 hot and 1 nuetral its is counted. Does thats sound right?
> 
> Still learning everyday!


 Not really. Let's say you have a 220volt electric dryer. The heater elements will use the 220v, and the tumbler will use the 110v, and the neutral WILL carry a current.


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## bengie

OK, so not all neutrals are considered CCC. Im so confused?


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## bengie

CORRECTION:

OK, so all neutrals are considered CCC. Im so confused?


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## RIVETER

bengie said:


> OK, so not all neutrals are considered CCC. Im so confused?


I can't think of a better way to explain it just now. I would always consider the neutral a conductor. A neutral is an intentionally grounded circuit conductor.


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## jeffsw6

RIVETER said:


> I can't think of a better way to explain it just now. I would always consider the neutral a conductor. A neutral is an intentionally grounded circuit conductor.


This is hard to explain, which is why 310.15(B)(4) contains the example (b) that reminds you not to exclude the neutral/grounded conductor from your number of CCCs if you are only using two phases of a three-phase system for the load(s). It's basically like an MWBC.

If you have a 120/240V dryer on a split-phase system, the total current in the cable will not exceed the combined current rating for the two ungrounded conductors, and in these cases the neutral need not be counted as a CCC.

If you put the same dryer on a 120/208V three-phase system but it is only wired to two phase conductors, then you must count the neutral as a CCC.


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## kbsparky

bengie said:


> When is a neutral considered a CCC ???


Simple answer: All the time.


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## jeffsw6

kbsparky said:


> Simple answer: All the time.


That is simple but it is actually not correct!


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## 10492

IMO 


99.99999999% of nuetrals carry current.

The only time I've ever seen a nuetral not carry current, is on paper.


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## kbsparky

jeffsw6 said:


> That is simple but it is actually not correct!


The neutral is always _considered_ a current-carrying conductor. Whether it actually carries current at all times or not is irrelevant.


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## jwjrw

kbsparky said:


> The neutral is always _considered_ a current-carrying conductor. Whether it actually carries current at all times or not is irrelevant.


Actually its pretty clear from what 480 posted. There are times you don't consider it a current carrying conductor.


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## raider1

A neutral is a current carrying conductor 99% of the time as previously pointed out, but for the purposes of ampacity adjustment in accordance with 310.15(B)(4) we don't need to count a neutral as a current carrying conductor if it only carries the unbalanced current from other conductors of the same circuit, ie.. The neutral of a multiwire branch circuit that does not have a major non-linear load.

Chris


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## jwjrw

Actually there was a thread last week and Dennis and Bob explained it pretty well in it. Easy to understand electrical for dummies language. Maybe thats why it made sense to me when I read their posts.:laughing:


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## MDShunk

I choose to remain neutral on this topic.


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## jwjrw

MDShunk said:


> I choose to remain neutral on this topic.


 
I would ask why but I'm scared your answer will shock me.


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## ampman

jwjrw said:


> I would ask why but I'm scared your answer will shock me.


 if i answer i may be grounded


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## jwjrw

ampman said:


> if i answer i may be grounded


By the wife no doubt!:jester:


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## Dennis Alwon

Think of it this way- we'll use single phase because it's easy. If you run a MWBC-- one neutral and 2 hots. we know that the hots will carry a potential 20 amps for a 20 amp circuit. 

Let's say Phase "A" has 15 amps and Phase "B" has 8 amps. Now the neutral will carry only the difference between Phase "A" & "B".

15-8= 7 amps on the neutral. There is no way you can ever have more than 40 amps run thru those wires. If "A" had 20 amps and "B" had 20 amps then the neutral would carry 0 amps. Still 40 amps total.

If "A" had 5 amps and "B" had 20 amps then the neutral would carry 15 amps (20-5). Total again is 40 amps


Now if we had 1 hot and 1 neutral we would have the same amount on the neutral as we would on the phase conductor.

Put 2- 2 wire circuits in a conduit and you have the potential for 20*4= 80 amps of current, which creates heat, vs the MWBC at 40 amps.

I hoe this is right and helpful.


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