Conduit Fill
Open the NEC Annex C fill calculator and apply a recommended upsize.
Last updated July 19, 2026
Conduit Fill opens the NEC Annex C fill calculator for the selected conduits (or every conduit on the level if none are selected). It shows each run’s fill percentage, a cross-section diagram, and a recommended larger size when it’s over the NEC limit (40% for 3+ conductors) — which you can apply in one click.
