Conduit Fill Calculator — NEC Chapter 9 (Free Tool)
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Conduit Fill Calculator
NEC Chapter 9 Tables 4 & 5 — check your fill before you pull wire.
🧰 What you'd need
- Conduit & fittings in your trade size → Allied Tube & Conduit
- THHN/THWN-2 conductors in your gauge → Cerro wire & cable
- Straps, bushings & pull accessories → Cables & accessories
Fill limits per NEC Chapter 9 Table 1: 53% (1 conductor), 31% (2), 40% (3+). Always confirm against the current NEC and your AHJ.
📖 Read the full guide: Conduit Fill Chart: Max THHN Conductors per EMT Size — charts, code references, and worked examples.
🧰 More free tools → — sizing, conversion, and payback calculators, all free.
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