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National Electrical Code Articles and Information

Based on the 2020 NEC

by Mark Lamendola

National Electrical Code Tips: Article 690 -- Solar Photovoltaic Systems, Part 3

Part III of Article 690 provides the requirements for disconnecting means used with photovoltaic systems. It was heavily revised from the 2017 NEC.

  1. A means must be provided to disconnect the PV system from all wiring systems including power, energy storage, and utilization equipment [690.13]
     
  2. You must install the disconnecting means at a readily accessible location. This rule is primarily to help firefighters. If the system is above 30V and the disconnecting means is readily accessible to unqualified persons, any door or hinged cover that exposes live parts when open must be locked or require a key to openosure that can be open [690.13(A)].
     
  3. Each disconnect must be marked per the (rather wordy) requirements of 690.13(B).




  4. As with the rule for service disconnects in Article 230, you have a maximum of 6 disconnects (switches or set of circuit breakers mounted in a single enclosure or in a group of separate enclosures) allowed for each PV system.
     
  5. The rules for the type of disconnect have been completely rewritten with the 2020 NEC. There are five types of disconnecting means permitted, one of which is a pull-out switch with the required interrupting rating [690.13(E)].
     
  6. The PV system disconnecting means must simultaneously disconnect the PV system conductors that are not solidly grounded from all conductors of other wiring systems [690.13(E)].
  7. The PV disconnecting means or its remote operating device must be lockable [690.13(E)].
     
  8. Isolating devices or equipment disconnecting means shall be installed in circuits connected to equipment at a location within the equipment or within sight and within 3ft of the equipment [690.15(A)].
     
  9. An isolating device isn't required to have an interrupting rating [690.15(B)].
     
  10. Equipment disconnecting means shall have ratings sufficient for the maximum circuit current, available fault current, and voltage available at the terminals [690.15(C)].
     

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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