National Electrical Code Top Ten Tips: Article 400, Flexible Cords and Cables

Please note, we do quote from copyrighted material. While the NFPA does allow such quotes, it does so only for the purposes of education regarding the National Electrical Code. This article is not a substitute for the NEC.

These are the 10 NEC Article 400 items we deem most important, based on the pervasiveness of confusion and the potential costs of same.

1. Don’t dismiss flexible cords and fixture wires as not deserving your attention. There's a reason why the NEC covers them in two separate articles. Flexible cord requirements are in Article 400 and fixture wire requirements are in Article 402.
   
   
2. The NEC does not consider flexible cords to be "a wiring method."
   
   
3. Article 400 applies to the cords and cables in Table 400.4, but it does not apply to the cables in Chapter 3 (e.g., NM, AC, or MC cable).
   
   
4. You must use the right cord (and fittings) for the application. This means you don't use a dry-rated cord in a wet location. The jacket material meets certain insulation properties and other characteristics only in the environment for which it is designed and approved.
   
   
5. Table 400.4 is the heart of Article 400. Notice, this is much more than "a list of extension cords." Look over the entries in this table, and you will see its importance immediately.
   
   
6. Chapter 3 deals heavily with ampacities for permanently installed wiring. Article 400 provides ampacities for flexible cords in  Tables 400.5(A) and 400.5(B).
   
   
7. The requirements for protecting cords from not smaller than 18AWG from overcurrent are in [240.5].
   
   
8. Look in [400.7], and you’ll see 11 permitted uses for flexible cords. Rather than try to memorize this list, take a few minutes to go through it and examine the logic behind the uses. A key factor is the need for movement at the device.
   
   
9. Look in [400.8], and you’ll see 6 uses not permitted for flexible cords. Again, apply the logic. Do not try to use flexible cords in place of Chapter 3 wiring methods.
   
   
10. Provide adequate support for flexible cords.