Technical FAQs

Ask a Question

Wire size table from the Digest 177 - Conductor ampacity based on the 2014 National Electric Code

What is the rating of the wire?
How much current can the wire carry?
What is the amp rating for each size of wire?
How do I size the wire?
NEC Table 310.15(B)(16)[Formerly 310.16]
Wire size table

Product Line and Environment:
This FAQ applies to installed products under the jurisdiction of the National Electric Code

The National Electric Code has information about ampacity rating of various types of conductors. With permission, some of this is reprinted on the inside cover of the Square D Digest. The attached file is a copy of that page from Square D Digest 177.

Example using NEC Table 310.15(B)(16)
  • The rating of 3/0 Copper wire, 75C, type THHW is 200A
  • The rating of 3/0 Aluminum wire, 75C, type THHW is 155A
Was this helpful?
What can we do to improve the information ?