Aerial fiber optic cables are used very commonly in optical communication nowadays. We can even see the aerial cables hanging in the pole around our daily life. In order to adjust to the harsh outdoor environment and prevent fiber theft, the aerial fiber optic cable is made up of different materials, which is not the same as a typical fiber optic cable. Today, we will take you to learn more about the aerial fiber optic cables.
What Is Aerial Fiber Optic Cable?
Aerial fiber optic cable is a type of fiber optic cables that is usually used for outside installation on poles. Due to its installation environment, the design of aerial fiber optic cable must consider to protect it from the destruction of the nature and man-made damage or theft. Aerial cable's laying method is not hard to implement as it can utilize the existing overhead pole line to install that saves more in construction costs and shortens the construction period. Aerial cables are mainly used for secondary trunk level and below and usually applied to flat terrain or low fluctuation area. They are easily affected by the natural disasters, such as typhoons, ice, floods etc. as well as the influence of an outside force and the mechanical strength weakening in themselves. Therefore, the failure rate of aerial fiber optic cables are higher than the pipeline or directly buried fiber optic cables.
Figure 1: Aerial fiber cable.
Types of Aerial Fiber Optic Cables
According to the installation methods, aerial fiber optic cables can be generally classified as two types: catenary wire and self-supporting. Catenary Wire Aerial Cable is regular outdoor loose tube cables that can be helically lashed to a messenger or another cable (common in CATV). Self-Supporting Aerial Cable, or All-Dielectric Self-Supporting (ADSS) cable (the common style such as Figure-8 Aerial Cables), has cable bonded to an insulated steel or all-dielectric messenger for support. ADSS Cables are usually made of heavier jackets and stronger metal or aramid strength members. Nowadays, the self-supporting aerial fiber optic cables are more widely used by people.
As a familiar self-supporting aerial cables, figure-8 self-supporting aerial cables are designed for easy and economical one-step installation and widely used in long-haul and building network communication. According to the structures and materials of the cables, there are several kinds of figure-8 self-supporting aerial fiber cbales in the market, such as GYTC8S, GYXTC8Y, GYXTC8S etc. We can see the differences between GYTC8S, GYXTC8Y and GYXTC8S through the detailed information below.
GYTC8S: GYTC8S is a typical self-supporting outdoor fiber optic cable. It's suitable for aerial applications while its nice moisture resistance performance and crush resistance performance are suitable for duct and buried method. The metal strength member is made up of stranded wires as the supporting part that are completed with a polyethylene sheath to be figure 8 structure. Corrugated steel tape armored and polyethylene outer sheath provide the crush resistance and gun shot resistance features. As the central strength, the steel-wire strength member improves the tensile strength. In addition, it is surrounded by the loose tube and water blocking system.
Excellent mechanical and environmental performance. Small cable diameter, self-supporting, easily to install. Low dispersion and attenuation. Corrugated steel tape armored and polyethylene outer sheath providing crush resistance and gun shot resistance features. Cross section shows figure 8. Stranded wires as self-supporting member providing excellent strain performance and convenient installation. Steel-wire strength member provides good tensility, ensures tensile strength. Water blocking system to improve the waterproof ability.
GYXTC8Y: GYXTC8Y is a light self-supporting cable with the figure-8 shape in the cross section that is suitable for installation in aerial environment for long haul communications. High tensile strength of stranded wires meet the requirement of self-supporting. It can also be used for duct and buried method. The metal strength member is similar to the GYTC8S. Steel wires and loose tubes filled with waterproof compound to ensure compact and longitudinally water blocking.
Figure 3: GYXTC8Y light self-supporting cable with the figure-8 shape.
Excellent mechanical and environmental performance. Small cable diameter, light cable weight, self-supporting, easily to install. Low dispersion and attenuation. Medium density polyethylene jacket: low friction installation, excellent protection from environmental hazards. Stainless steel or galvanized steel self-supporting. Load-supporting element is made of zinc-coated wire provides high resistance grade to long tension. High strength loose tube that is hydrolysis resistant. Light self-supporting cable with the figure-8 shape.
GYXTC8S: GYXTC8S is also suitable for installation in aerial environment for long-haul communications. This kind of figure-8 aerial cables is usually for 4-core to 12-core types. The water resistant tape provides water tight property. Corrugated steel tape and the polyethylene outer sheath provide crush resistance and gun shot resistance. The figure-8 steel wire works as self-supporting member providing excellent strain performance and convenient installation.
With small cable diameter, light cable weight, self-support. Excellent mechanical and environmental properties. Proper design and precise control for fiber excess length. Corrugated steel tape and the polyethylene outer sheath ensure crush resistance and gun shot resistance. The water resistant tape provides water tight property.
Tips for Aerial Fiber Optic Cables' Installation
When implementing the aerial fiber optic cables' installation, there are always two ways: lashing a fiber optic cable to a steel messenger or direct installation of self-supporting figure-8 aerial cables. There are some tips for better aerial installation.
1. Make clear what Problems we might meet during the installation. The following three points are the mostly common problems:
Dead end pole: Dead end pole is a utility pole on which self-supporting figure 8 aerial cable or a steel messenger is tensioned and terminated into a dead-end fixture. Messenger span: Messenger span refers to the length of continuous steel messenger tensioned between two dead-end poles. Intermediate poles: Intermediate poles are all the poles between two dead-end poles.
2. A perfect Planning solution is necessary before any aerial cable installations:
Preparation: Cable route survey should cover all necessary parties including utilities, street depart, etc. In addition, you should get approval from all involved parties. Sufficient clearance for new cable along the right of way should be confirmed during the route survey. Try to use the possible existing poles in order to save cost and shorten the construction period. Fiber optic cables should occupy the uppermost available communications space on a pole due to the nature of them. Sufficient clearances must be maintained between fiber optic cables and electrical power cables on joint-use poles. In the process, you need to refer to current National Electrical Safety Code for the proper clearances. ou must to evaluate the existing dead-end pole and see whether they can withstand the stresses during aerial cable installation. You have to evaluate whether temporary guying is needed in order to relieve the temporary unbalanced loading during cable installation. Splice locations are chosen to allow for the longest possible continuous cable spans and a minimum number of splices. In addition, they should be easily accessible to a splicing vehicle. This process is usually confirmed during the cable route survey. Aerial installation should never be done in wet conditions. What's more, to ensure safety, all personnel must be properly trained for pole line work. Fiber optic cables (including all-dielectric cables) should be properly grounded when installed in the vicinity of high-voltage power cables.
3. Safety during installation:
To minimize the risks of an accident in the work area, follow the existing rules for setting up warning signs, barricades, manhole guards, and cones. Before pulling cable directly from a figure-8 configuration, make sure that the area inside the loop of the cable (figure-8) is clear of personnel and equipment. Failure to do so may result in injury to the personnel or damage to the cable. Ensure that the tools and equipment used for the cable installation are in proper working order. Improperly functioning equipment may damage cables or cause injury to personnel. Be careful when working near electrical hazards, if electric lines are passing through or near the right-of-way where installation is being performed. Bond all metallic components in the underground system together. At all points where anyone may come in contact with the metallic components of the underground cable system, ground the bonded metallic components to a proper earth ground to avoid electric hazards produced by power lines or any other means.
We mention aerial fiber optic cables and something about the aerial installation above. However, after learning this tutorial, it often comes down a question. When considering aerial fiber optic deployment, which types of aerial cable solution is most cost effective for you. ADSS cable is more expensive than loose tube cable (using in catenary wire installation), but labor and material costs can be lower for ADSS. And while ADSS hardware on a cost-per-pole basis is higher, this is often offset by the elimination of strand or lashing wire. In a word, explore your options based on your situation and then decide what makes the most sense for you. For example, in areas where a strand is already in place, catenary wire aerial fiber optic cables could be more cost-effective, while the opposite might be true in an area without a strand in place.