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National Electrical Code Articles and Information

Based on the 2017 NEC

by Mark Lamendola

National Electrical Code Top Ten Tips: Article 522 -- Control Systems for Permanent Amusement Attractions

  1. Article 522 applies to control circuit power sources and conductors for permanent amusement attractions.
  2. A control circuit carries the electrical signals for controlling the equipment, but does not carry the power. Example: The 120V motor speed control and start/stop circuits belong to the controls, the 480V power to the motor itself does not.
  3. What does the NEC mean by "permanent?" For Article 522, it means that transporting or relocating the equipment is impractical [522.2]. That does not mean it's impossible. Basically, if you don't typically remove the equipment at the end of the season (or during), it's permanently installed.
  4. Only "qualified personnel" can service this equipment [522.7]. An untrained operator with a pair of pliers isn't a qualified person. A factory-trained technician with specific training on this specific equipment is.
  5. The two types of control circuits are power-limited (under 30V and under 1,000A) and non power-limited. The latter cannot exceed 300V [522.10].
  6. The overcurrent protection devices for power-limited control circuits can't be rated for more than 167% of the following: VA rating divided by the rated voltage [522.10].
  7. You can't use aluminum conductors in the control circuits [522.20].
  8. If using conductors 16AWG or smaller, ensure they comply with Table 522.22.
  9. Though it's a poor engineering decision, you can run control and power wiring in the same raceway. But to do so you must meet the criteria of 522.24(B).
  10. Where wet contact is likely to occur, ungrounded 2-wire control circuits are limited to 30VDC (or 12.4VDC peak for DC that's continually interrupted at a rate of 10 to 200 Hz) [522.28].

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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