Neutral function in 120 or 240

[Electric-Light]

121117-2044 EST

Electric-Light:

In your example the neutral has a current of 7.5 A if both loads are resistive. It can be zero by changing the nature of one or both of the loads. If you add an equal 15 A resistive load to the third phase then the neutral current drops to 0.
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Right, but the third phase doesn't go to that portable classroom, so the neutral serving that portable classroom will carry 15A.

sqrt ((A^2+B^2+0)- (A*B-0-0))
How did you get 7.5A ?

 

[gar]

121117-2204 EST

Electric-Light:

You are correct 15 A.

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