Fiber optic cables are typically buried between 12 and 36 inches (30–90 cm), depending on installation environment, soil conditions, and load requirements. In high-load areas such as roads or backbone routes, burial depth can reach 48 inches (120 cm) or more. The NTT Group is investigating further coverage expansion of optical-fiber networks for 5G (fifth-generation mobile communications network) base-station demand and popularization of Internet-of-things devices. NTT has thus developed an on-road surface-wiring optical-cable technology that does not. 1. The methods described are intended for guideline use only, as it is impossible to cover all the various conditions that may arise during an installation. Individual. Direct burial fiber optic installation eliminates conduit cost but demands the right cable construction, proper bedding, and precise depth to meet NEC and Telcordia GR-20 requirements.
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