# Is this OK?



## 480sparky (Feb 1, 2009)

jasonec500 said:


> 15 amps? I'm not an electrician, but because the hots are different poles don't they cancel each other out or something like that?


Whether they completely cancel each other out or not depends on if it's a single or a three-phase system.

And you thought electricity was easy........


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## ampman (Apr 1, 2009)

480sparky said:


> Single or three phase?


 dors not matter


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## 480sparky (Feb 1, 2009)

ampman said:


> dors not matter


Yes it does.

Single phase, there would be 0 amps on the neutral. Two loads on a three-phase would be calculated with this formula:

SqRt[(A²+B²+C²-(A*B)-(A*C)-(B*C)].



Insert 15 into any two, such as A and B, you get

SqRt[(15²+15²+0²-(15*15)-(15*0)-(15*0)].

SrRt[(225+225+0-(225)-(0)-(0)]

SqRt[(450-225)]

SqRt[225] = 15.



The only way to balance the load so there's no current on the neutral is to impress a 15a load on the C phase.

Click here for Mike Holts' article on the matter.


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## ampman (Apr 1, 2009)

ampman said:


> dors not matter


 instead of saying "does not matter" i should have said "either one"
i have been to many of mike holts classes and i get it(a great instructor)
and by the way electrical is easy


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## Magnettica (Dec 19, 2006)

ampman said:


> instead of saying "does not matter" i should have said "either one"
> i have been to many of mike holts classes and i get it(a great instructor)
> and by the way electrical is easy


Shhhhh!


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## 480sparky (Feb 1, 2009)

ampman said:


> instead of saying "does not matter" i should have said "either one"
> i have been to many of mike holts classes and i get it(a great instructor)
> and by the way electrical is easy


 The question was:


ampman said:


> i have a question (i already know the answer) on a multiwire branch circuit 2 hots 1 neut. each hot wire load is 15 amps how much is the neut load.


"Either One" would produce two different answers.


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## thom (Nov 3, 2006)

480sparky said:


> The question was:
> 
> "Either One" would produce two different answers.



Actually, the question was "is this ok?"

The OP did not ask if there was a difference in load on the neutral wire in a single phase vs a three phase system. 

The only real choices are A) yes, B) no, C) maybe

The OP did not tell us if what code was relevant so the answer to that would need to be included in the three choices.


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## ampman (Apr 1, 2009)

480sparky said:


> The question was:
> 
> "Either One" would produce two different answers.[/quote
> "either one" like "does not matter" means to pick one
> i have run across electricians who always think they have to prove themselves


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## 480sparky (Feb 1, 2009)

ampman said:


> "either one" like "does not matter" means to pick one
> i have run across electricians who always think they have to prove themselves


You said you knew the answer, and I provided two. Which one did you have in mind?


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## ampman (Apr 1, 2009)

480sparky said:


> You said you knew the answer, and I provided two. Which one did you have in mind?


 either one


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## 480sparky (Feb 1, 2009)

ampman said:


> either one


Does it matter?


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## ampman (Apr 1, 2009)

thom said:


> Actually, the question was "is this ok?"
> 
> The OP did not ask if there was a difference in load on the neutral wire in a single phase vs a three phase system.
> 
> ...


 i am new to posting on websites not new to electrical contracting and i think i highjacked this thread with my question not the first time i hade to stand in the corner


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