Formula to calculate neutral current

[darekelec]

Good morning

May I ask You for a formula to calculate current on neutral conductor in 2 scenarios?;
1) 2 hot conductors, 1 neutral taken from 120/208V 4 wire 3 phase system
2) 2 hot conductors, 1 neutral taken from 120/240V 3 wire single phase system

Thank You

 

[infinity]

The second one is easy just subtract the smaller number from the larger. The first one is more complex I can't remember it off of the top of my head but someone will chime in.

 

[roger]

The first would be any two of the following formula.

(A^2 + B^2 + C^2 – AB – AC – BC).

 

[roger]

Oooops, I left out SQRT.
it would be SQRT (A^2 + B^2 + C^2 – AB – AC – BC)

 

[darekelec]

In the above given formula I have current on A (leg) and current on B (leg) what number do I plug in for C (leg)

 

[infinity]

In the above given formula I have current on A (leg) and current on B (leg) what number do I plug in for C (leg)

Leave the C out of the formula.

 

[jim dungar]

In the above given formula I have current on A (leg) and current on B (leg) what number do I plug in for C (leg)

Use zero.

Remember this is a simplified formula.
It is easy to use, but it will not work well if the Power Factor of the currents are not close to unity. At the extreme it would give really inaccurate results if the A-N current was all inductive and the B-N current was all capacitive.