neutral current calculator
Compute neutral current from unbalanced 3-phase line-to-neutral loads. Enter Ia, Ib, Ic (A) to get In (A) instantly—plus formula, sample table, and FAQs.
calculate neutral amperage
The 3-phase, 4-wire system is a system where the neutral current is measured as the vector sum of the phase currents. Perfectly balanced loads mean that the neutral has ~0 A; any imbalance introduces a non-zero neutral current, which you can easily determine without trial and error as a direct function of Ia, Ib, and Ic.
Formula & Table Summary:
In = sqrt( Ia^2 + Ib^2 + Ic^2 - Ia*Ib - Ib*Ic - Ic*Ia )
Inputs: Ia, Ib, Ic in amperes (RMS). Output: In in amperes (RMS).
three-phase neutral current
This neutral current calculator gives a rapid approximation of the current in the neutral of a 3-phase 4-wire system where there are unbalanced line-to-neutral loads. Give the phase currents Ia, Ib, and Ic (in amperes), and the tool carries out the vector sum using the 120 electric phase difference to yield the neutral current In. It is perfect to test panelboard loading, neutral size on the feeder, and to diagnose imbalance caused by single-phase loads on a three-phase supply. It assumes fundamental frequency currents, ignoring harmonics: adding non-linear loads, such as switch-mode power supplies, may introduce triplen harmonics that, after summation, yield more current in the neutral than the fundamental result. There is also the central formula, a small input-to-output data table, and exposition of common cases (such as when one phase is unloaded or how equal loading results in approaching zero) in the form of concise, frequently asked questions. An easy pre-check before more thorough load studies or measurements by a clamp meter or power analyzer.
distribution board neutral amps
| Ia (A) | Ib (A) | Ic (A) | In (A) |
|---|---|---|---|
| 20 | 20 | 20 | 0.00 |
| 30 | 10 | 10 | 20.00 |
| 25 | 18 | 12 | 9.00 |
| 40 | 0 | 0 | 40.00 |
| 16 | 22 | 19 | 7.75 |
