Construction Codebooks, Estimating Guides, NEC Info
National Electrical Code Explanations
Based on the 2008 NEC
National Electrical Code Top Ten Tips: Article 342 through Article 362 -- Conduits
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 320 through NEC Article 340 items we deem
most important, based on the pervasiveness of confusion and the
potential costs of same.
- NEC Article 342 through 362 contain the requirements for various
types of conduit. Remember that, and your life will be much easier.
- Note that conduit is a subcategory of raceway. EMT is not a type
of conduit It's a type of raceway.
- Each Article in this series provides the uses permitted and the
uses not permitted.
- NEC Article 350 presents requirements for Liquidtight Flexible
Metal Conduit: Type LFMC. Note that the smallest allowable trade
size is 1/2, and the largest allowable trade size is 4. There are
limits on length and bending.
- Article 356 provides the requirements for Liquidtight Flexible
Nonmetallic Conduit: Type LFNC. The requirements are similar to
those of Type LFMC, but there are some differences. For example,
there are no exceptions to the requirement for installing a
- NEC Article 352 presents the requirements for Rigid Nonmetallic
Conduit: Type RNC. Any fittings used with the conduit must be
Listed. You cannot use plumbing pipe fittings with RNC. There are
limits on where you can used this. Note, also, that you must provide
expansion fittings with RNC.
- NEC Article 354 presents the requirements for Nonmetallic Conduit
with Conductors: Type NUCC. You cannot use Type NUCC in exposed
locations or inside buildings.
- All types of conduit must be supported.
- You cannot use any conduit to support other wiring.
- Refer to the tables in Chapter 9 for raceway fill requirements.
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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, what 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 application, 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.
Here are a couple more NEC resources:
Cafe Code Site |
Joe Tedesco's National Electrical Code
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