Duct Installation Of Fiber Optic Cable

Innerduct is available in ribbed corrugated and smooth.

Duct installation of fiber optic cable.

Innerduct is a way to subdivide the duct and to provide for future cable pulls. As compared to the duct the installation process is relatively very quick. The ducts and innerducts should be kept free of debris and maintained watertight at all times. Compressed air is injected in the duct inlet after few hundred meters of cable is pushed into the duct.

The most common cables used for this type of installation are steel armored outdoor fiber cables. In underground fiberoptic cable installation cables can be buried directly in a trench or placed into a buried duct. Compressed air flows at high speed through the duct and along the cable. The pushing force is applied mainly near the cable inlet by a pushing device.

Duct cable can be hand pushed or pulled in via tape string into a micro duct. Rodding is used to clear the duct passage and install the pulling rope using fiberglass pushrods. Underground direct installation directly buried installations are most common for long cross country installations. After the fiber optic cable is installed into a duct or innerduct end plugs should be installed to provide an effective water seal.

Testing fiber optic cable on the reel all optical fiber cables must be tested while on the reel prior to deployment. Loose tube cables can be blown jetted or pulled into a duct or conduit that will protect the cable during its installed lifetime. Preparations for duct installation using an air blowing method. Cable blowing is the process of installation of optical fiber cable into a pre installed duct.

Three 1 25 inch inside diameter i d innerducts can usually be pulled into a 4 inch duct. Proper size and installation of the innerduct is critical for ease of cable installation. 1 micro ducts can also be placed directly into larger telecommunications conduits or can be factory assembled into a composite unit of multiple micro ducts. Ducts and innerducts should be sized to meet present and future cable installation requirements.

Most micro duct fiber cable products have a tension limit of 300 lbs or lower versus 600 lbs for typical outside plant fiber cable. Generally there are two approaches for optical cable installation. Installation crews must use blowing equipment specifically designed and tested for micro duct fiber cable to avoid damage to the cable. Micro duct cable is blown jetted into the micro duct.

Table 1 commonly used cable types for various osp applications underground cable innerduct micro ducts. The most commonly deployed dielectric outdoor cable design with fiber counts from 2 to 288 fibers and up to 432 fibers for gel filled. Installing cable is a time consuming and expensive process so it is important to ensure the cable is good before installation.