Ch 9 Table 8: Conductor Properties

Conductor properties including resistance and reactance for voltage drop calculations.

Source: NEC 2020

The Math Shortcut

Calculate Voltage Drop

Size (AWG/kcmil)	Stranding	Copper Res (Ohms/kFT)	Alum Res (Ohms/kFT)
14	1	3.07	5.04
12	1	1.93	3.17
10	1	1.21	1.99
8	7	0.778	1.28
6	7	0.491	0.808
4	7	0.308	0.508
2	7	0.194	0.319
1/0	19	0.122	0.201
2/0	19	0.0967	0.159
3/0	19	0.0766	0.126
4/0	19	0.0608	0.100

Professional Usage

This data is provided for informational purposes only. Always verify with the latest edition of the National Electrical Code (NFPA 70) and consult with a licensed electrical professional or AHJ (Authority Having Jurisdiction) before performing any electrical work.

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