POWER · CALCULATOR

Neutral current calculator

Free neutral current calculator: get fundamental neutral current from phase a current, phase b current and phase c current. With the formula shown.

Written by Chameera Sampath · Not yet reviewed by a licensed electrician. See the methodology.

US (NEC) only · NFPA 70 / NEC — locally adopted editionDefaults are US values. Verify the locally adopted NEC edition and project data.Official reference ↗

Project inputs

Measurements

Phase A current

Phase B current

Phase C current

Updates as inputs change. Unit changes preserve the same physical values.

THE MATH BEHIND THE ANSWER

Method & assumptions

IN = √(IA² + IB² + IC² − IAIB − IBIC − ICIA)

120° phase separation and identical power factor. Triplen harmonics are excluded and can increase neutral current.

Results do not check every aspect of an electrical installation. The calculators follow US (NEC) practice only; a regional preset changes defaults such as voltage and units, and no result certifies NEC compliance.

Sources and validation →

Worked example

Phase A current: 20 A · Phase B current: 15 A · Phase C current: 10 A

Fundamental neutral current: 8.66 A

This example uses the stated inputs; results for the entered values appear above.

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