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National Electrical Code Articles and Information

NEC Quiz: Article 396 Answers

by Mark Lamendola

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  1. The wiring method in question is messenger-supported wiring. It's an exposed wiring support system. That is, there's a cable or other support that the conductors are affixed to [396.2]. You can look at any overhead "utility wires" between poles and see this wiring method. There are four ways this can be done, and factory-assembled ariel cable is one. See the others in 396.2.

  2. There are three situations in which this wiring method may be used [396.10]. Basically, you can use it with the cable types listed in Table 396.10(A):
    A. Under the conditions described in Article 396.10 or under the conditions described in the other Articles/Sections listed in Table 396.10(A).
    B. In industrial establishments where conditions of supervision and maintenance ensure only qualified persons service the cables (and you can use it for MV cable in this situation, also).
    C. In Hazardous locations where permitted in the relevant Chapter 5 Article.

  3. You can't use it in hoistways. And, as usual, you can't use it where subject to physical damage [396.12].

  4. Article 396 does not specify the hardware you can use, but it does specify support requirements [396.30(A)]. You must use hardware suitable for this intended use [110.3]. If you're not sure what hardware you can use with the messenger cable you bought, ask your electrical distributor to find out for you.
  5. This wiring method doesn't use couplings and connectors. But make sure any conductor splices and taps are made and insulated by approved methods [396.56].



How the NEC is arranged

  1. The first four Chapters of the NEC apply to all installations.
  2. Article 90 precedes Chapter One, and establishes the authority of the NEC.
  3. Article 80 follows the body of the NEC; it exists as Annex H. It provides the requirements for administration.
  4. Chapters 5, 6, and 7 are the "special" chapters, covering special: occupancies, equipment, and conditions (in that order).
  5. Chapter 8 provides the requirements for communications systems.
  6. Chapter 9 provides tables.
  7. The appendices provide mostly reference information.
  8. Appendix D contains examples that every NEC user should study.

Try your NEC moxy:

  • Do you know the difference between bonding and grounding? Hint: Look in the NEC, Article 100.
  • Does the NEC refer to grounding incorrectly in any of its articles? Yes! So be careful to apply the Article 100 definitions. Don't ground where you should bond.
  • When doing motor load calculations, which Article covers hermetic motors? Answer: While Article 440 covers the application of hermetic motors, it does so only by amending Article 430 because hermetic motors are a special case of motors. For motor load calculations, refer to Article 430.
  • Does the NEC provide a voltage drop requirement? Yes! It does so in a special case, which is Article 648 Sensitive Electronic Equipment. But for general applications, it does not provide a requirement; it merely provides a recommendation in a couple of FPNs.
  • Take our Code Quizzes.

Remember other applicable codes, rules, standards, and references:

  • OSHA's electrical worker safety rules.
  • IEEE standards.
  • NETA standards.
  • NFPA standards.
  • International Codes (if applicable to the installation).
  • State Codes (if the state has them).
  • Local ordinances and permit requirements.
  • Local fire codes.
  • Manufacturer requirements or guidelines.
  • Customer security requirements.
  • Industry standards.
  • Your company's own internal standards, practices, and procedures.
  • Engineering drawing notes.



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