Southwire® Conduit Fill Calc

About this app

Southwire has created this great tool to help electricians, engineers and contractors answer the question, “What size conduit do I use” per the NEC®, includes fill percentages and jam probability.  If you do not have the NEC book handy or do not want to spend time manually calculating the Conduit Fill %, this is the right app for you. The app provides quick and easy navigation.  Enter the Conduit Type and Size and specify your conductors.  The App will calculate the Conduit Fill % as per NEC Guidelines.  Southwire Company is North America’s leading manufacturer of wire and cable used in the distribution transmission of electricity.  Throughout its history, our company has sought to deliver power through our products, our service and by helping empower our customers, employees and communities. The App Answers the question, “What size conduit do I use” includes fill percentages and jam probability per the NEC®.  With one click, you can email your results.

Added new banner and improved the look of the button that takes you to the user-defined outer diameters screen.

Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.

1. First observed Aug 10, 2026 · 3:24 PM Free