NFPA LiNK® is your window to productivity, providing instant digital access to NFPA codes and standards to support the way you work best.
Learn to help your business become more efficient and effective with capabilities for seamless search, personalization, and shared knowledge.
This video shows how to determine conduit fill capacity using NFPA 70®, National Electrical Code® (NEC®), 2023. When a conduit houses conductors of only one size, open the annex section to save time. If conductors of multiple sizes are contained in the same conduit, find calculation tables in chapter 9.
Annex C’s tables can be extremely helpful if all of the conductors within a conduit are the same size. From your LiNK dashboard, open the 2023 NEC. Scroll down to the annexes, expand the contents, and select Annex C for the full list of tables. Each table is labeled for conduit type and conductor size. To avoid a common mistake on exams, make sure to use the correct table for standard vs. compact conductors.
When a conduit’s conductors have more than one size, go to chapter 9. From the sidebar on the left of your screen, expand the heading for the chapter contents. To meet conduit fill requirements for multiple conductor sizes, refer to tables 4 and 5 when making your calculations. Conductor types with alternate values based on their insulation are indicated by an asterisk.
For more info about using NFPA LiNK to get the job done right, visit www.nfpa.org/link.
www.nfpa.org/link
NFPA, LiNK, NFPA 70, National Electrical Code, NEC, conduit, fill, conductor