National Electrical Code Top Ten Tips: Article 424: Fixed Electric Space Heating Equipment

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 424 items we deem most important, based on the pervasiveness of confusion and the potential costs of same.

1. Even though you use heat intermittently, any fixed heater must be considered a continuous load [424.2(B)] for purposes of branch circuit sizing.
    
2. If there's not enough space to allow for combustible materials, you can't install the heater [424.13].
    
3. You must provide a disconnecting means within sight of the heater [424.19].
    
4. Thermostatic controllers can also serve as the disconnecting means, provided they comply with 424.20.
    
5. All switches and breakers used as a disconnecting means must be of the indicating type [414.21].
    
6. Don't assume overcurrent protection automatically meets code. Carefully examine 424.22 for each installation.
    
7. If you install space heating cables, note that the NEC devotes Part V of Article 424 to this equipment.
    
8. If you install duct heaters, note that the NEC devotes Part VI of Article 424 to this equipment.
    
9. If you install resistance-type boilers, note that the NEC devotes Part VII of Article 424 to this equipment.
    
10. If you install electrode-type boilers, note that the NEC devotes Part VIII of Article 424 to this equipment.