NEC Conduit Fill Tables - NEC Table C Conductor Size - AWG / kcmil - THHN / THWN

Sep 23, 2026

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Conduit fill tables summarize NEC Table C conductor fill limits for THHN/THWN insulation across common conductor sizes in both AWG and kcmil formats. The tables list permissible fill counts by conduit type, including EMT, RMC, IMC, and additional category variants, and provide results for various conduit cross-section sizes. Values are presented in structured rows for conduit size fractions (e.g., 1/2 to 3) and columns by conductor gauge, supporting direct selection and verification when planning wiring and conduit capacity.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Conduit Fill Tables

Conductor sizing inputs (AWG / kcmil, THHN / THWN)

Conduit types and allowable fill values (NEC Table C)

| CONDUIT FILL TABLES – NEC TABLE C CONDUCTOR SIZE – AWG / kcmil – THHN / THWN | | | | | | | | | | | | | | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | SIZE | | 14 | 12 | 10 | 8 | 6 | 4 | 3 | 2 | 1 | 1/0 | 2/0 | 3/0 | 4/0 | 250 | 300 | 350 | 400 | 500 | 600 | 750 | | 1/2 | EMT | 12 | 9 | 5 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | | | | RMC | 13 | 9 | 6 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | | | | IMC | 14 | 10 | 6 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | | | 40 | 11 | 8 | 5 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | | | | 80 | 9 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | | | | | | | | | | | | | | | FMC | 13 | 9 | 6 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | | | | LT | 13 | 9 | 6 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | | | 3/4 | EMT | 22 | 16 | 10 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | RMC | 22 | 16 | 10 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | IMC | 24 | 17 | 11 | 6 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | 40 | 21 | 15 | 9 | 5 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | 80 | 17 | 12 | 7 | 4 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | | FMC | 22 | 16 | 10 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | | LT | 22 | 16 | 10 | 6 | 4 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | 1 | EMT | 35 | 26 | 16 | 9 | 7 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | RMC | 36 | 26 | 17 | 9 | 7 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | IMC | 39 | 29 | 18 | 10 | 7 | 4 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | 40 | 34 | 25 | 15 | 9 | 6 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | 80 | 28 | 20 | 13 | 7 | 5 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | | | FMC | 33 | 24 | 15 | 9 | 6 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | | LT | 36 | 26 | 16 | 9 | 7 | 4 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | | 1 ¼ | EMT | 61 | 45 | 28 | 16 | 12 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | RMC | 63 | 46 | 29 | 16 | 12 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | IMC | 68 | 49 | 31 | 18 | 13 | 8 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | 40 | 60 | 43 | 27 | 16 | 11 | 7 | 6 | 5 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | 80 | 51 | 37 | 23 | 13 | 9 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | FMC | 52 | 38 | 24 | 14 | 10 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | | | LT | 63 | 46 | 29 | 16 | 12 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | 1 ½ | EMT | 84 | 61 | 38 | 22 | 16 | 10 | 8 | 7 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | RMC | 85 | 62 | 39 | 22 | 16 | 10 | 8 | 7 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | IMC | 91 | 67 | 42 | 24 | 17 | 10 | 9 | 7 | 5 | 4 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | 40 | 82 | 59 | 37 | 21 | 15 | 9 | 8 | 7 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | 80 | 70 | 51 | 32 | 18 | 13 | 8 | 7 | 6 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | FMC | 76 | 56 | 35 | 20 | 14 | 10 | 6 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | | LT | 81 | 59 | 37 | 21 | 15 | 9 | 8 | 7 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | | 2 | EMT | 138 | 101 | 63 | 36 | 26 | 16 | 13 | 11 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | | | RMC | 140 | 102 | 64 | 37 | 27 | 16 | 14 | 11 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 2 | 1 | 1 | 1 | | | IMC | 149 | 109 | 68 | 39 | 28 | 17 | 15 | 12 | 9 | 8 | 6 | 5 | 4 | 3 | 3 | 2 | 2 | 1 | 1 | 1 | | | 40 | 135 | 99 | 62 | 36 | 26 | 16 | 13 | 11 | 8 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | | | 80 | 118 | 86 | 54 | 31 | 22 | 14 | 12 | 10 | 7 |

FAQs

What do these conduit fill tables cover?

They provide NEC Table C conductor fill limits for THHN/THWN insulated conductors, organized by conductor size (AWG/kcmil) and conduit size.

Which conduit types are included in the tables?

The tables list allowable fill values by conduit type such as EMT, RMC, IMC, and other listed variants shown in the table rows.

How do I use the tables to choose a conductor size?

Select the conduit size row, then read across to the column matching the conductor’s gauge (AWG) or kcmil size to get the permissible conductor count for the selected conduit type.

Sep 23, 2026

Upload by Bulrr