Microducts

They have a typical size ranging from 3 to 16 mm and are installed as bundles within larger ducts.

Microducts are typically small-diameter, flexible, or semi-flexible ducts designed to provide clean, continuous, low-friction paths for placing optical cables that have relatively low pulling tension limits.

As stated in industry requirements document Telcordia GR-3155[1] Generic Requirements for Microducts for Fiber Optic Cables, microduct products are expected to: GR-3155 states that the basic types of duct are smoothwall, corrugated, and ribbed.

The selection of a particular duct design is dependent on those characteristics that are important to the end user.

Pre-lubricated ducts may be either permanently impregnated with anti-friction compounds or coated with liquid lubricant during manufacture (see GR-3155).

Failure to do this may result in the cable seizing up rather than reducing the friction coefficient of the duct.

At the completion of the process, all of the fibers in the optical cable must be tested to ensure that no damage has occurred.

In Fibre to the Home (FTTH), where multiple branches are present in the network, an Optical Distribution Network is used to branch the cables from a roadside cabinet or pit that contains optical equipment and is fed from the Central Office With microduct cabling, bundles of small microducts may be installed in larger protective duct (e.g., PVC conduit).

The fibre counts have grown up to 144 per cable and can be installed in microducts of only 8 mm inner diameter.