Estimate neutral wire size from load amps, unbalanced load percentage, system type, wire material, voltage, and run length. This calculator gives a planning estimate for copper or aluminum neutral conductor sizing.
Neutral current:
The calculator estimates neutral current from the load current and the neutral load percentage you enter.
Adjustment factors:
Continuous load and nonlinear load factors can increase the adjusted neutral amp estimate.
Wire size:
The adjusted neutral amps are compared to a simplified ampacity table for copper or aluminum conductors.
A neutral wire size calculator helps estimate a neutral conductor size for branch circuits, feeders, subpanels, and multiwire circuits.
It can help with panel planning, feeder planning, subpanel wiring estimates, multiwire branch circuits, load balancing, conduit planning, and cable planning.
Your result shows estimated neutral wire size, neutral amps, adjusted amps, conductor material, circular mils, approximate diameter, estimated run weight, voltage, system type, and comparison scenarios.
Neutral wire size is based on the calculated neutral load. Some circuits require a full-size neutral, while some feeders may allow neutral load calculations when permitted by code.
Often it is the same size, especially on many branch circuits. In some feeder situations, neutral sizing may be based on calculated neutral load, but final sizing must follow code.
No. The neutral is a current-carrying grounded conductor. The ground wire is an equipment grounding conductor used for fault clearing and bonding.
No. This is a simplified planning tool. Always verify neutral conductor sizing, load calculations, harmonic loads, subpanel rules, derating, and local code requirements with a qualified electrician.