National Electrical Code ExplanationsBased on the 2014 NEC
National Electrical Code Tips: Article 800, Communications Circuits, Part 3
- The requirements for the protection devices of communication circuits are in Article 800, Part III. This takes up slightly less than 2 pages.
- A listed primary protector must be provided on each circuit run (even partially) in aerial wire or cable not confined within a block [800.90(A)].
- A listed primary protector must be provided on each circuit run within the block containing the building served if it's exposed to accidental contact with conductors operating at over 300V (to ground) [800.90(A)].
- The installation of primary protectors must comply with 110.3 [800.90(A)].
- Primary protectors may be fuseless or fused.
- The requirements for fuseless primary conductors are in [800.90(A)(1)]. Basically, this gives you three conditions under which such protectors are permitted.
- The requirements for fuses primary conductors are in [800.90(A)(2)]. Basically, this says if your application doesn't meet any of the three conditions for using fuseless protectors then you must use fused ones. These requirements also define what a fused protector is and states how its terminals must be marked.
- You have to install the primary protector as close as practicable to the point of entrance [800.90(B)].
- You can't install the primary protector in a hazardous location [800.90(C)].
- If you install a secondary protector in series with the indoor communications wire and cable between the primary protector and the equipment, it must be listed for that purpose [800.90(D)].
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.
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