National Electrical Code Top Ten Tips:Article 320 through Article 340, 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 320 through NEC Article 340 items we deem most important, based on the pervasiveness of confusion and the potential costs of same.

1. NEC Article 320 through 340 contain the requirements for various types of cable. Remember that, and your life will be much easier.
    
2. Each Article in this series provides the uses permitted and the uses not permitted.
    
3. NEC Article 320 presents requirements for type AC: Armored Cable. This kind of cable has a metallic jacket. While many people assume it's the most durable of all cables and can be used anywhere, this is not true.
    
4. Article 322 and Article 324 address two types of flat cable assembly. Only one of them is designed for use under carpet squares.
    
5. NEC Article 326: You cannot use Integrated Gas Cable (Type IGS) inside buildings.
    
6. Article 328 provides the requirements for Medium Voltage Cable (Type MV).  You cannot use it on systems above 35 kV (35,000 volts).
    
7. Article 330 provides the requirements for Metal-Clad Cable (Type MC). Note, this differs from armored cable.
    
8. Article 334 provides the requirements for various kinds of Non-Metallic Sheathed Cable (Types NM, NMC, and NMS).
    
9. Article 338 provides the requirements for Service Entrance Cable ((Type SE and Type USE).
    
10. Article 340 provides the requirements for Underground Feeder and Branch-Circuit Cable (Type UF).