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National Electrical Code Articles and Information

Based on the 2020 NEC

by Mark Lamendola

National Electrical Code Tips: Article 685 -- Integrated Electrical Systems

Many electricians work on integrated electrical systems without being aware of the fact and without applying Article 685. The same is true of electrical engineers whose area of responsibility includes such systems. Partly, this is because they are ill-defined. If you read the scope statement [685.1] you see a sort of definition which is rather long. Read our first five tips to get a more clear understanding of what an integrated electrical system is. You might be working on one now and not even know it! This is a super-short article once you get past the scope and information about which other articles apply; only three short sections..

  1. Article 685 does not cover unit equipment [685.1].
  2. Article 685 does cover integrated equipment required for orderly shutdown, where such shutdown is required for safe operation [685.1]. An example would be the reactor safety systems on the reactors of nuclear power plants.
  3. The NEC calls the equipment "integrated" because it exists as a unit [685.1]. A good clue as that something is integrated is that is has its own wiring diagrams. As an example, the reactor safety system of a nuclear reactor has its own associated drawings. They aren't mixed in with general lighting or other systems in the building.
  4. The conditions of maintenance and supervision must ensure that only qualified persons (trained and authorized) service this equipment [685.1].
  5. The system must have effective safeguards, and they must be properly maintained [685.1].
  6. Table 685.3 lists specific Sections from Chapters 2 and 4 as "Other Articles" that apply.
  7. For UPS systems, Sections 645.10 and 645.11 apply.
  8. You must connect the output of an integrated electrical system power source per 705.12(A).
  9. Overcurrent devices can be accessible [685.10]. And they can be placed high enough to be out of reach of unauthorized personnel. For example, you can install them on a mezzanine or, alternatively, you can locate them high on a wall such that a personnel lift is required to reach them.
  10. The two-wire DC circuits (if used) for these systems can be ungrounded [685.12]. Control circuits can be ungrounded, if they are under 150V and supplied by separately derived sources [685.14].

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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