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National Electrical Code Articles and Information

NEC Quiz: Article 220, Part One Answers

by Mark Lamendola

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1.      [220.1]. It provides the requirements for calculating branch-circuit, feeder, and service loads. This makes it one of the most important Articles to study and understand.

2.      [220.3]. More than 10. Table 220.3 shows over two dozen entries, some of which are repeated.

3.      [220.3]. No. This is a common source of misunderstanding and misapplication. These other Articles use Article 220 as the starting point. In fact, the first four Chapters apply generally to all installations [Figure 90.3]. Chapters 5 through 7 supplement or modify Chapters 1 through 4 [Figure 90.3].

4.      [220.5(A)]. No.

5.      [220.5(A)]. You must use nominal system voltages of 120V (not 115V), 120/240V (not 110/220), 240V, 347V, 480Y277V, 600Y347V, and 600V.

6.      [220.5(B)]. No. In such a case, the NEC permits you to drop that fraction of an ampere. Note that this is for the results of a calculation.

7.      [220.12]. Use Table 220.12 to determine general lighting loads by occupancy.

8.      [220.14(D)]. Calculate these based on the maximum volt-ampere rating of the equipment and lamps for which the luminaire is rated.

9.      [220.14(E)]. 600 VA.

10.  [220.14(I)]. Except as covered by 220.14(J) and 220.14(E)—dwelling occupancies and banks/office buildings, respectively—the minimum is 180VA for each single or multiple receptacle in one yoke. But if a single piece of equipment consists of a multiple receptacle comprised of four (or more) receptacles (four example, a four-gang receptacle box or strip), then the minimum is 90VA per receptacle. This means, for example, you would allow 180VA for a duplex receptacle unit but 360VA for a four-gang receptacle unit.


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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