Based on the 2008 NEC
National Electrical Code Articles and Information
National Electrical Code Top Ten Tips: Article 520 -- Theaters and Similar Locations
- Article 520 applies to all structures or parts of structures used for presentations and/or performances. Basically, if it has a stage, auditorium, or audience seating area, it's covered by Article 520.
- If you use nonmetallic raceway, it must be encased in at least 2 in. of concrete [520.5(A)], unless it's for Article 640 circuits.
- Article 520 puts a twist on raceway fill. If using a raceway other than an auxiliary gutter (or aux raceway), the normal raceway fill requirements of Table 1, Chapter 9 apply. Otherwise, the sum of the cross-sectional area of all contained conductors at any cross section can't exceed 20% of the interior cross-section of the gutter (but the 30-conductor limit of 366.22 and 376.22 does not apply) [520.6].
- Any branch circuit that supplies receptacles can supply stage set lighting [520.9].
- Portable equipment used outdoors must be supervised by qualified personnel and barriered from access to the public [520.10].
- Stage switchboards must be of the dead-front type [520.21].
- Stage switchboard feeders can be one of the only three types described in 520.7(A).
- Footlights, border lights, and proscenium lights are limited to circuits of 20A or less [520.41(A)].
- A road show connection panel is a type of patch panel, and it must comply with 520.50(A) through (D).
- There are many types of portable stage equipment other than portable switchboards (arc lamps, PDUs, busbars, receptacles, etc.), and these are covered in Part V of Article 520. Requirements address such issues as festoons, conductor types, conductor ampacity, and adapters.
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Learn more about:
How the NEC is arranged
- The first four Chapters of the NEC apply to all installations.
- Article 90 precedes Chapter One, and establishes the authority of the NEC.
- Article 80 follows the body of the NEC; it exists as Annex H. It provides the requirements for administration.
- Chapters 5, 6, and 7 are the "special" chapters, covering special: occupancies, equipment, and conditions (in that order).
- Chapter 8 provides the requirements for communications systems.
- Chapter 9 provides tables.
- The appendices provide mostly reference information.
- 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.