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National Electrical Code Articles and Information

Based on the 2011 NEC

by Mark Lamendola

National Electrical Code Tips: Article 690 -- Solar Photovoltaic Systems, Part 1

Only about 15% to 20% of the work of installing a Solar Photovoltaic (PV) System is electrical. But that electrical portion can easily result in disaster if not done correctly. Thus, Article 690 provides requirements for that portion.

  1. Article 690 does not cover small solar-powered devices, such as patio lamps, flashlights, automobile ventilators and other assorted gadgets.
     
  2. Article 690 does cover solar power systems, including those that are interactive with other power systems  [690.1].
     
  3. The NEC provides a simple diagram that clearly illustrates PV system components [Figure 690.1(A)].
     
  4. The NEC provides a set of simples diagram that clearly illustrate solar photovoltaic (PV) system components in three common system configurations [Figure 690.1(B)]. These are stand-alone, hybrid, and interactive.
     
  5. A hybrid system is one comprised of several power sources [690.2 and Figure 690.1(B)]. For example if you combine a wind turbine generator with a solar system, you have a hybrid system.
     




  6. A system is "interactive" if it connects to the power network [690.2 and Figure 690.1(B)].
     
  7. A charge controller is different from a diversion charge controller. The former controls the dc voltage (or dc current) use to charge a battery. The latter regulates the battery charging process by diverting power from energy storage to the load or to the utility [690.2].
     
  8. You still must apply Chapters 1 through 4, but where the requirements differ from Article 690 then you go with the Article 690 requirements [690.3].
     
  9. If the PV system operates in parallel with a primary source of electricity (e.g., the electric utility), then the requirements in 705.14, 705.15, 705.32, and 705.143 apply [690.3].
     
  10. If you install a PV system in a hazardous location (as defined by OSHA and as defined in Article 500), you must apply the relevant Articles 500 through 516. A location is hazardous if the presence of combustibles is high enough to risk a fire. If the combustibles are gases, dust, or fibers, the location is Class I, Class II, or Class III respectively.

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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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