Part I of Art. 770 of the National Electrical Code (NEC) provides the general requirements for optical fiber cables. Although these are not current-carrying conductors, how and where you install them can affect “the practical safeguarding of persons and property from hazards arising from the use of electricity” [90.1].
Part I includes the usual requirements for cables, such as not blocking ceiling access [770.21], mechanical execution of work [770.24], removing the accessible portion of abandoned cables [770.25], and installing in such a way as to not substantially increase the spread of fire [770.26].
Part II provides requirements for cables that enter buildings, which are:
- Overhead, including clearances and attachment limitations.
- Underground, including those bundled with various kinds of current-carrying conductors and those that are unlisted.
Part III provides requirements for grounding, bonding, or interrupting cables, depending on whether they enter a building or terminate outside it.
Part IV provides extensive detail on how these cables should be grounded. Always ensure the fiber optic cable system grounding electrode is bonded to the power grounding electrode system [770.100(D)].
Part V covers installation methods within buildings.
