Feeder neutral as CCC???

[LarryFine]

Turn off any one phase and the neutral will carry the same as the other two phases for a total of 60 amps, no change.

Another way to look at it is, if you start with a 20a balanced-load condition, and reduce one phase's current by, say, 5a, the neutral current will increase by the same 5a.

In other words, a line conductor(s) must be subject to less than full current for there to be any neutral current. (I won't comment on the "total of 60 amps" statement. )

 

[roger]

(I won't comment on the "total of 60 amps" statement. )

Why not?

Roger

 

[LarryFine]

Why not?

Because, unlike three 20a circuits that are in phase, there is only a "total" of 20a with three 20a loads supplied by one MWBC. The opposing current flows see to that.

 

[roger]

Because, unlike three 20a circuits that are in phase, there is only a "total" of 20a with three 20a loads supplied by one MWBC. The opposing current flows see to that.

Yes, but for the simplicity of the example and what happens in the second part of the example it makes the point.

Roger

 

[LarryFine]

It do.

 

[Smart $]

Yes, but for the simplicity of the example and what happens in the second part of the example it makes the point.

Roger

Call it 60A contributing to I?R loss (power lost in the form of heat)... and move on