Skip to main content



Q: Can indoor/outdoor fiber optic cables be direct buried or hung?

A: Generally, the materials and constructions of indoor/outdoor fiber optic cables prohibit them from being direct buried. Unlike outdoor only fiber optic cables (also called OSP for Outside Plant), the jacket materials used for indoor/outdoor cables must help the cable pass the appropriate flammability tests for indoor use, such as plenum and riser. Outdoor only cables typically use materials that are very robust (harder) and have other qualities that prevent them from passing indoor flammability tests. Outdoor only cables are not rated, meaning they have not passed any flammability test and cannot be used indoors per U.S. national electrical code. Burying a cable can also crush it so it is typically recommended that only cables that state “direct bury” in their characteristics be buried. Hanging an indoor/outdoor fiber optic cable is acceptable. This can be done with a lashing machine or even UV resistant tie-wraps for very short runs. Indoor/outdoor fiber optic cables should be UV resistant and have a fungicide in the jacket material as well. (Hitachi’s do.) This ensures that regardless of the cables jacket color, it can be installed for long-term outdoor use as well as indoor use.

page top