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National Electrical Code Articles and Information

Based on the 2020 NEC

by Mark Lamendola

National Electrical Code Top Ten Tips: Article 669 -- Electroplating

Electroplating has been around a long time and products made with this process are ubiquitous. Every time you see a chrome bumper, you are looking at an electroplated object. That chromium finish was put on the steel bumper by a process called electrolytic deposition or electroplating. Silver is another metal that's commonly electroplated, but not onto car bumpers. Any shop or factory that has an electroplating operation must comply with additional EPA and OSHA requirements.

  1. Article 669 applies to the installation of the electrical components and accessory equipment that supply the power and controls for electroplating, anodizing, electropolishing, and electrostripping [669.1].
  2. Article 669 refers to electroplating, anodizing, electropolishing, and electrostripping all as electroplating. That is for simplicity's sake, not for any technical reason. In a given shop or factory, the equipment may have a different name as well. If it's using an electric means of depositing a metal finish such as chromium onto another metal such as steel, then for NEC purposes it is electroplating [669.1].
  3. Any equipment used for electroplating must be identified for such service [669.3]. This seems obvious, but suppose you are asked to install a machine at a small shop. The owner has rigged up his own electroplating machine by modifying a machine used for another purpose. The owner theoretically could identify this machine for use as an electroplating machine. But if something goes wrong, what will his insurance company say? Does the manufacturer of the previously unmodified machine have any liability? The testing lab (e.g. UL) certification has been nullified, so no that manufacturer stands little chance of being found liable. But who installed that machine? There's the party most likely to endure a costly lawsuit. Make sure before installing this equipment that it has been properly engineered and identified by some qualified party or authority for that use. If, for example, a machine rebuilding firm engineered this equipment that firm is in the business of building new equipment from old and has the expertise to do so. But Joe Blow Jury Rigger is not and does not.
  4. The branch circuit supplying the equipment must have an ampacity of at least 125% of the total connected load [669.5].
  5. Section 669.5 also says that busbars supplying this equipment must have an ampacity that conforms to the requirements of 366.23. But Article 366 is about auxilliary gutters. Those are a form of raceway, not a conductor (366 comes right after 362, which is for electrical nonmetallic tubing). So is this an error? No, read carefully. The busbar ampacity must be comply the limits for bars stated in 366.23; those limits are not for the gutter, but for the bars. So, for example, bare copper bus bar in a sheet metal auxilliary gutter can't exceed 1000A/ square inch.
  6. If the system does not exceed 60V of direct current, insulated conductors can be run without insulated support, but only if they are protected from physical damage [669.6(A)]. Please note that insulated supports come in handy for protecting insulated conductors from phyical damage.
  7. If the system exceeds 60V of direct current, insulated conductors can be run with insulated support, but only if they are protected from physical damage [669.6(B)].
  8. If the system does not exceed 60V of direct current, you can use bare copper or aluminum conductors if you support them on insulators [669.6(A)].
  9. If the system exceeda 60V of direct current, you can use bare copper or aluminum conductors if you support them on insulators and guard them against accidental contact up to the point of termination [669.6(B)].
  10. If there's more than one power supply to the equipment, you must provide a disconnecting means on the dc side of each power supply [669.8(A)]

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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