construction code books

Home | Search | About us                  Bookmark and Share

nec training

National Electrical Code Articles and Information

Based on the 2020 NEC

by Mark Lamendola

National Electrical Code Top Ten Tips: Article 555, Marinas and Boatyards

  1. Article 555 covers the installation of wiring and equipment for just about any place where boats are docked, repaired, or fueled. This used to exclude private and non-commercial docking facilities of single-family dwellings in older editions of the NEC, but they are also covered [555.1].
  2. The Electrical Datum Plane is the most important concept of Article 555. The definition, once in 555.2, is now in Article 100. Understand that this plane is defined based on the highest water level (e.g., tide), not some average.
  3. Pier power distribution systems cannot exceed 250V phase to phase (nominal) [555.5].
  4. Transformers and their enclosures must be identified for wet locations [555.7(A)].
  5. Permanent safety signs must give notice of electrical shock hazard risks, and must comply with the three requirements of 555.10(1), (2), and (3).
  6. Bond everything metallic that is non-current carrying [555.13].
  7. Many older sections have been removed over time. For example, 555.15, 555.17. 555.19. and 555.21 all appeared in the 2011 NEC. The 2020 NEC omits these, going from 555.13 to 555.30.
  8. Enclose shore power receptacles in listed marina power outlets, enclosures listed for wet locations, or listed enclosures protected from the weather [555.32(A)(1)].
  9. When you bond per 55.13 and 555.37, ensure your equipment grounding (bonding) conductor is an insulated conductor with a continuous outer finish that is either green or green with at least one yellow stripe [555.37(B)].
  10. Each floating building must be served by one set of feeder conductors from its service equipment [555.1].

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.




Codebookcity is a subsidiary of Mindconnection, LLC. If you have any questions, comments, or concerns, please write to sales @ We do want your business.