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National Electrical Code Top Ten Tips: Article 404, Switches

Please note, we do quote from copyrighted material. While the NFPA does allow such quotes, it does so only for the purposes of education regarding the National Electrical Code. This article is not a substitute for the NEC.

These are the 10 NEC Article 404 items we deem most important, based on the pervasiveness of confusion and the potential costs of same.

  1. Don’t dismiss switches as not deserving your attention. There's a reason why the NEC has finally devoted an entire Article to them. Even the trade magazines, such as EC&M, are writing about switches.
     
  2. You must wire switches such that you are switching only the ungrounded (hot) conductor. Don't switch the neutral or the ground.
     
  3. Put switches in enclosures listed for such a use. Putting a switch in an enclosure that is not listed for use as a switch enclosure puts you at risk for liability, and puts the switch users at risk of injury to property and people.
     
  4. Don't run other wiring through switch enclosures. These enclosures have one purpose: to act as switch enclosures. They are not pullboxes, junction boxes, or raceways.
     
  5. If you put a switch in a wet location, use an enclosure rated for wet locations. Don't use a GFCI as a license to violate this rule. A GFCI is not intended to overcome all problems that may arise from putting a switch in an enclosure not rated for the intended use.
     
  6. Mount switches such that gravity won't close them. That means "OFF" is down and "ON" is up.
     
  7. If you are grouping or ganging switches, arrange them so they are operating at similar voltages. The NEC requirement is that the voltage differential not be more than 300V, unless you accommodate the difference by placing such switches in their own enclosures.
     
  8. Faceplates must completely cover the opening in which a switch is mounted.
     
  9. You can use general-use dimmer switches only for the control of permanently installed incandescent luminaires, unless they are listed for other loads and you install them per manufacturer's directions.
     
  10. You must observe the wire-bending space requirements of 404.3 and Table 312.6(B).

   

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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.

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