Auxiliary Gutter & Wireway Sizing Calculator

Enter conductor details to calculate the minimum gutter/wireway size per NEC requirements.

Notes:

  • 16 AWG conductors are based on TFN insulated conductors.
  • 14 AWG - 1000 kcmil conductors are based on THHN or THWN insulated conductors.
  • If more than 30 current-carrying conductors are present, they must be derated per NEC 310.15.
  • Splices and taps must be accessible and cannot take up more than 75% of the cross-sectional volume of the gutter or wireway per NEC 366.56/376.56.

DISCLAIMER:

Calculations are based on NEC 366.22 (20% fill) and 312.6(A) for bending space. Always perform due diligence and verify calculations are correct for your specific application. This calculator is not to be used in lieu of consultation with a licensed electrician, contractor, electrical engineer, or other qualified professional. Always confirm calculations and specifications with a licensed professional before implementation. We take no liability for incorrect calculations, omissions, or any damages resulting from use of this tool. Local codes and regulations may differ from NEC requirements.