Unbalanced Current

[Alwayslearningelec]

What is the unbalanced current?


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(C)(1).

 

[infinity]

It's the normal neutral current that is in a MWBC.

 

[Alwayslearningelec]

It's the normal neutral current that is in a MWBC.

Well that doesn't help me understand.

 

[Jraef]

In an MWBC, the two hot lines are required to be from opposite poles of a two pole breaker, sharing a common neutral wire. That way, the neutral current on either line occurs at the opposite sequence from the other and they don’t combine. The neutral currents may not be equal, but they are not happening at the same time on the wire.

 

[roger]

Well that doesn't help me understand.

 

[Joe.B]

This helped me understand this concept:

 

[augie47]

Will this help ??

The sketch on the left shows the 5 amp unbal;ance current.

 

[ggunn]

Well that doesn't help me understand.

In a two wire 120V circuit the line and neutral currents are the same. In a three wire 240V circuit the neutral current is the difference between the L1 and L2 currents because the line currents are inversions of each other and send current to the neutral that are "180 degrees out of phase" from each other, and they cancel so that if L1 and L2 currents are equal, the neutral current is zero.

 

[retirede]

Research and understand Kirchoff’s laws of voltage and current. Once you you that, many real-world conditions (including this one) are easier to understand.