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National Electrical Code Articles and Information

National Electrical Code Top Ten Tips: Article 225 -- Outside Branch Circuits and Feeders

Based on the 2020 NEC

by Mark Lamendola

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 225 items we deem most important, based on the pervasiveness of confusion and the potential costs of same.

  1. Read the scope carefully. In many instances of disagreement with the electrical inspector, folks are misapplying 225 [225.1].
  2. Table 225.3 clearly shows were other NEC Articles apply to specific equipment and conductors.
  3. Overhead conductors outdoors must be insulated or covered (per Article 100, a covering is not insulation) when within 10 feet of a building—except as stated [225.4].
  4. 225.7 gives various rules for outdoor lighting. Note, there are clearances established for circuits exceeding 120V.
  5. 225.14 provides the rules for open conductor spacing. For example, "Open conductors shall be separated from open conductors of other circuits or systems by not less than 100 mm (4 in.).
  6. 225.18 is "Clearance for Overhead Conductors and Cables." This has often been a source of contention in court. It’s best to exceed the requirement by a foot or two, as design and installation are two different things and being off by an inch can burn you, despite the fact that it’s substantial compliance and obviously satisfies the intent of the Code. For one thing, a crane operator won’t know you are an inch low, and that can get somebody killed. These are minimal heights. Pay attention to the type of area a cable will pass over, and use the highest clearance if in doubt. Also, create a clear path for fire ladder equipment and other emergency apparatus. Sometimes, simply locating the overhead conductors at the same height but 15 feet to the east (or wherever) reduces danger by orders of magnitude. Can you route to the backside of the building and avoid the (for example, walkway) altogether? Meeting clearance requirements doesn't ensure nobody will get electrocuted. Use a combination of measures, wherever possible.
  7. 225.19 gives the clearances from buildings (1000V or less) —the comments we gave for 225.18 also apply here.
  8. 225.34 addresses the grouping of disconnects. You can have a single disconnect on a service. But, if you have more than one, you must group all of them (except a fire pump disconnect, which has special requirements). You can have a maximum of 6 disconnects per service entrance.
  9. 225.37 covers an issue most installers routinely ignore or inadequately comply with. You must have a circuit directory or plaque (with some exceptions noted) to identify the circuits. The intent here is not to have vague text, but to clearly identify the circuits. This isn’t just for the convenience of the owner. It’s also for the use of the first responders (e.g., for stopping an electrocution), fire department workers and other emergency workers. It is illegal to shirk responsibility here, and this particular violation can carry heavy personal penalties for all concerned. Some of the new products on the market make this job much easier and the outcome much better. Check with your panel supplier to see what's available.
  10. 225.60 and 225.61 provide more information on clearances, such as those over sidewalks.



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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