Optical Fiber & Communications
Continuing Education Units (CEU): 0.10
Expected Duration: 1 Hour
This self-paced online course explains NEC articles that address fiber optic cable systems and communication systems. These articles are very similar in their arrangement and organization and have very similar requirements. They are not identical, however, and the differences are important to understand.
Upon completion you should be able to:
- Identify similarities and differences between Article 770 and Chapter 8 and how these two articles compare with Articles 725 and 760.
- Identify areas that Article 770 and Chapter 8 have in common.
- Explain key features of Article 770.
- Identify key features of Chapter 8.
Who Will Benefit
Anyone whose job involves designing, reviewing, evaluating or installing fire protection systems, including: designers, installers, engineers, electrical contractors, technicians, project managers, fire marshals, and architects.
- Article 770 (optical fibers, cables and raceways) is in some ways very similar to articles 725 and 760, but the organization, numbering, and applications more closely match the articles in Chapter 8 (communications systems).
- Article 770 and Chapter 8 are similar in many respects. Permitted cables must be listed and marked for their intended use, such as "P" for plenum use, "R" for riser use and no marking or "G" for general use. Provisions for cable substitution and removal of abandoned cables are also similar.
- There are significant differences, however. While Article 770 excludes requirements of Chapter 2 and Article 300 and then reinstates some of them selectively, Chapter 8 is not covered by any requirements of Chapters 1-7, unless it includes language that specifically applies those requirements.
- Article 770 permits unlisted cables only in certain conditions. It also requires protection for metallic elements of optical fiber cables coming into a building from outside, as well as specifying grounding methods, wiring methods and raceway requirements. Optical fibers are permitted within the same composite cable with higher-powered or non-power-limited circuits only if they are functionally related.
- Most rules for communications circuits in Chapter 8 are similar to those in Article 770, except for Article 810, which addresses antennas.
- In addition, the requirements for primary protectors in Article 800 are very different, mandating a listed primary protector for any communication circuit that runs outside, leaves the block and has any part that is aerial.