Insulated Conductor Dimensions

Common insulated-conductor dimensions used by the conduit fill engine.

Source: Chapter 9 Table 5 and Table 5A
Edition: 2023
Updated: 2026-07-27
Scope: United States

Lookup Table

Which conductor area is used in conduit fill?

Size	THHN / THWN-2	XHHW-2	Use
12 AWG	0.0133 sq in	0.0181 sq in	Branch circuits
10 AWG	0.0211 sq in	0.0243 sq in	Branch circuits
6 AWG	0.0507 sq in	0.0590 sq in	Feeders
2 AWG	0.1158 sq in	0.1333 sq in	Feeders

Insulated Conductor Dimensions. Derived as a task-focused reference view; verify marginal work against the source and the AHJ edition.

Calculated against the NEC 2023 edition using Chapter 9 Table 5, Chapter 9 Table 5A. Confirm the edition adopted by your AHJ, which may differ and may carry local amendments.

Not covered by this tool

Local amendments and equipment markings can be stricter than this reference view.
Marginal values should be checked directly against the adopted edition.
This page is a routing aid and does not replace the owning calculator for project-specific inputs.

Data last verified 2026-07-27