310.15(C)(1): Adjustment Factors

Adjustment Factors for More Than Three Current-Carrying Conductors.

Source: NEC 2020

The Math Shortcut

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Number of Conductors	Percent of Values in Tables
4 - 6	80%
7 - 9	70%
10 - 20	50%
21 - 30	45%
31 - 40	40%
41 and above	35%

Related NEC Tables

Table 310.16: Allowable Ampacity Table 310.15(B)(1): Temp. Correction

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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