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National Electrical Code Articles and Information

NEC Quiz: Article 215 Answers

by Mark Lamendola

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1.      [215.2(A)(1)]. Article 220. The Parts are Parts III, IV, and V.

2.      [215.2(A)(1)]. Any adjustment or correction factors (e.g., temperature).

3.      [215.2(A)(2)]. Where the feeder conductors carry the total load supplied by service conductors with an ampacity of 55A or less.

4.      [215.2(B)(1)]. The ampacity of the feeder conductors cannot be less than the sum of the nameplate ratings of the transformers supplied by those feeder conductors.

5.      [215.2(B)(2)]. The ampacity of the feeder conductors cannot be less than the sum of the nameplate ratings of the transformers plus 125% of the designed potential load of the utilization equipment that will be operated simultaneously.

6.      Article 240. See Part I, if under 600V. See Part XI, if over 600V.

7.      [215.4(A)]. True. Two or three sets of 3-wire feeders, or two sets of 4-wire or 5-wire feeders, may use a common neutral.

8.      [215.11]. It must have a grounded conductor that is electrically connected to a grounded conductor of the system supplying the autotransformer. Note that this can defeat the purpose of using an autotransformer, in many cases. If so, move it downstream in the distribution so it supplies a branch, rather than a feeder.

9.      In 200.6 and 250.119, respectively.

10.  [215.12(C)]. You must identify each ungrounded conductor by system, wherever it is accessible.


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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