The two most common outdoor fiber optic cable installations are pole line aerial installation and underground cable installation. Underground cable installation can be directly buried underground or in a buried pipe.
Direct burial installation
Direct burial installations are most common for long cross country installations. The cables are plowed in or buried in a trench; the installation process can be very fast. The most common type of cable is used in the directly buried cables is outdoor steel armor.
Underground duct installation
Fiber optic cables can also be pulled through underground ducts, which protect the cables from harsh environment. Underground duct installation also provides opportunity for future expansion without the need to dig. This is the most common approach in urban areas. Another benefit is that the fiber optic cable no armor can be used to make installation easier.
Preparation before underground cable installation
1. The right to receive appropriate one-way permits
2. Identify existing underground utilities such as buried cables, pipes
3. Investigate the soil condition in order to determine the installation depth, whether duct should be used, the type of fiber cable should be used and plowing equipment needed.
Buried cable technology
1. Plowed under
Cultivated land is faster than cuts in the fiber optic cable. But the process must be carefully monitored to prevent damag to the cable.
Fiber optic cable can also be cut. This process is slower than farming; however, it allows a more control cable installation. Dig trenches can by hand or by machine.
3. Directional boring
Directional boring technique is used where the surface cannot be engaged in such as high, the railway crossing. On the contrary, a drilling machine is used to bore a few inches beneath the surface of the hole diameter, a pipe is out of the mouth of the cave, and then dragged into fiber optic cable pipe.
1. Cable installation depth: up to 40 inches
The depth that fiber cables should be buried is determined by the soil conditions and surface usage. In cold region, fiber optic cable is buried below the frost line, usually prevent damage of cable is the ground frost.
2. Keep the trenches as straight as possible
Fiber cable trenches should be straight, and should be formed at the bottom of the trench. Backfill soil could also be used to load evenly distribution cable and protect the cable.
3. Fiber cable warning labels should be buried directly above the cable
Fiber optic warning cables are typically buried directly above the cables to warn future digging operations. Or concrete slabs can be buried below the warning label but above the cables to provide even more protection.
4. Whenever armor fiber cable used, they should be properly grounded
In the directly buried installations, steel armored fiber optic cable is often choose for their strength and protection from rodents bite. A very important thing to remember is proper grounding cable. They should be down-to-earth in all end points, splicing and the entrance of the building. Steel armored cable should be connected to ground using compression type clip. Cable near ground is then bolted to the ground terminal strip.
5. Fiber optic cable minimum bending radius should always be observed during installation.