Conduit · Fill

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EMT conduit-fill helper for common THHN/THWN copper conductor sizes. This version uses the real NEC fill-percentage rule set and published EMT conduit-fill counts for more than two conductors.

Raceway type

Trade size

Conductor size

Number of conductors

Quick result

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Choose conduit, conductor size, and conductor count.

Applicable NEC fill limit: —

Published EMT max count (3+ conductors): —

Tool mode: —

Status: —

Authority block

Code authority	NEC Chapter 9 Table 1 fill rules: 53% for 1 conductor, 31% for 2, 40% for over 2.
Practical table basis	Published EMT THHN/THWN conduit-fill charts corresponding to NEC Table C style counts for more than two conductors.
What this version does	Exact count check for EMT with more than two same-size THHN/THWN conductors.
What this version does not do yet	Exact one- and two-conductor area math, mixed conductor sizes, or full raceway-type coverage.

EMT THHN/THWN max conductors used by this version (3+ conductor fill basis)

Trade size	14 AWG	12 AWG	10 AWG	8 AWG	6 AWG	4 AWG	3 AWG	2 AWG	1 AWG	1/0	2/0	3/0	4/0	250	300	350	400	500

This table is included so the page remains transparent and auditable. The comparison result comes directly from the selected row and conductor size.