310.16 Ampacity Table.
Code Change Summary: Restructuring of Article 310 results in restoring the most commonly used ampacity table’s beloved title.
For 9 years now the electrical community has had a mouthful every time the most commonly used ampacity table was mentioned in conversation or spoken of during a seminar. Back in the 2008 NEC® and before, the most commonly used ampacity table was Table 310.16. Simple enough. With restructuring that occurred in the 2011 NEC®, Table 310.16 was retitled “Table 310.15(B)(16)”.
Table 310.16 was so well known before the 2011 code change that every code cycle since, including the 2017 NEC®, there has been the following reminder at the top of the table: “Table 310.15(B)(16) (formerly Table 310.16)”.
In the 2020 NEC®, with the restructuring that occurred from moving the medium voltage conductor requirements from Article 310 to new Article 311, ampacity Table 310.15(B)(16) has been given its old title back and is now, once again, Table 310.16.
In addition, the notes under the table have been reworded for usability and the title of the table has been shortened up significantly. See code language below.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
Table 310.15(B)(16) (formerly Table 310.16) Allowable Ampacities of Insulated Conductors Rated Up to and Including 2000 Volts, 60°C Through 90°C (140°F Through 194°F), Not More Than Three Current-Carrying Conductors in Raceway, Cable, or Earth (Directly Buried), Based on Ambient Temperature of 30°C (86°F)*
2020 Code Language:
Table 310.16 Ampacities of Insulated Conductors with Not More Than Three Current-Carrying Conductors in Raceway, Cable, or Earth (Directly Buried)