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National Electrical Code Articles and Information

Based on the 2017 NEC

by Mark Lamendola

National Electrical Code Top Ten Tips: Article 515 -- Bulk Storage Plants

  1. Article 515 covers any portion of a property where flammable liquids are received and subsequently stored in bulk [515.1].
  2. A property or portion thereof that qualifies for Article 515 requirements is a bulk plant or terminal.
  3. For any bulk plant or terminal that is also a Class I location, you must apply Table 515.3 [515.3].
  4. Table 515.3 is slightly more than two pages long and consists of four columns: Location, NEC Class I Division (1 or 2), Zone (0, 1, or 2), and Extent of Classified Area.
  5. All fixed wiring in a Class I location that is a bulk plant or terminal must comply with the applicable provisions of Article 501 or Article 505 [515.7]. The exception to this rule is underground wiring.
  6. Underground wiring in a Class I location that is a bulk plant or terminal must comply with 505.8.
  7. Wiring above a Class I location that is a bulk plant or terminal must be in metal raceways, Schedule 80 PVC, or in one of a few other approved raceways [515.7(A)].
  8. Any fixed equipment that might make arcs or sparks has to be of the totally enclosed type or be constructed so as to prevent sparks or hot metal particles from escaping [515.7(B)].
  9. Any gasoline dispensers in this area must comply with Article 514 [515.10].
  10. Ensure there are no differences of potential between metallic objects. Per Article 250, don't ground metallic enclosures and raceways; bond them [515.16].

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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