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National Electrical Code Articles and Information

NEC Quiz: Article 430 Answers, Part 5

by Mark Lamendola

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  1. They protect motor feeder conductors against overcurrents due to short circuits and grounds [430.61]. They do not protect against motor circuit overloads.

  2. The run-on sentence in 430.62(A) is incomprehensible and needs to be translated into English. That said, the gist of it is the rating or setting of the feeder OCPD can't exceed that of the branch circuit OCPD. This is counterintuitive, because we think of feeders as being larger than branch circuits. For a greater understanding of this rule, read 430.24 and see Informative Annex D, Example D8.

  3. Yes [430.61(B)], and that is how it would be done in a typical load side power distribution scheme. Again, read 430.24.
  4. Where a feeder supplies a motor load and other loads, the feeder OCPD must have a rating at least as much as the sum of the other loads plus three quantities. What are those three quantities?
  5. Is there an exception to the rule above? If so, what is it? If not, why isn't there one?



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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