construction code books

Home | Search | About us                  Bookmark and Share

 
nec training

National Electrical Code Articles and Information

NEC Quiz: Article 250, Part Seven Answers

by Mark Lamendola

Back to Quiz

  1. [250.30(A)(1)]. Zero. It must be unspliced.
     

  2. [250.30(A)(2)]. The size of the derived phase conductors.
     

  3. [250.30(A)(6)]. You don't ground them. You bond them. See Article 100 definitions and 250.104(D).
     

  4. [250.30 (B)(1)]. Nothing. While the language of the NEC requires you to "ground" the equipment of an ungrounded separately derived system, that isn't what you do. Grounding won't help. If you read the actual requirements, you will see this is just an incorrect word choice in the NEC and the requirement is actually that you bond that equipment.
     

  5. [250.34]. False. Grounding it won't prevent shock. Also, the requirement to ground it exists only if the generator fails to meet two conditions that are typical of nearly every generator application (detailed in 250.34).

 

Don't take your electrical exam twice

Journeyman Electrical Exam Prep | Master Electrician Exam Prep

Learn more about: Harmonics | Motors | Power Quality
 

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.

 

 

Master the NEC | Solve Harmonics | Become a Motor Maintenance Guru

Codebookcity is a subsidiary of Mindconnection, LLC. If you have any questions, comments, or concerns, please write to sales @ mindconnection.com. We do want your business.