ADSS includes not only aramid reinforced all-dielectric fiber optic cables
Self-supporting non-electric overhead fiber optic cable accessories wedge wedge accessories
Self-supporting feeder-free aerial optical cables, commonly referred to as optical cables used by major telecom operators. Non-power overhead optical cable accessories are not unavailable in the electrical field, but are different from power overhead optical cable accessories in terms of cost and electromagnetic field sensing.
Self-supporting non-electric overhead optical cable mainly utilizes the tensile strength of the optical cable itself to withstand the cable weight, wind load and ice load. From the material, there are metallic structure and non-metallic structure. The representative products are figure 8 optical cable (F8) and ADSS. The ADSS mentioned here includes not only aramid reinforced all-dielectric cables, but also fiber optic cables designed with non-metallic reinforcing elements such as glass fibers and other high-strength fibers, braids, and fiber tubes.
According to telecom design specifications, the distance between line towers is 50m-70m, with a maximum distance of 120m. The tower is not too high, and the straight non-crossing pole is generally 8 meters, which is based on the consideration of line safety design requirements and total cost. Therefore, the tensile strength of telecommunication aerial optical cables is not as great as that of power aerial optical cables. Usually, a pulling force of 5kN is sufficient. Of course, this depends mainly on factors such as cable structure, weight, tower spacing, design sag and climatic conditions.
F8 cable and short span, small force ADSS can be fixed with wedge fittings.
Design principles and application features
The design principle of the wedge fitting comes from the wedge. Wedges used in life work by converting downward forces to the level of an object, while wedge-shaped complexes are designed to convert forward forces into lateral forces of an object. Under the premise of a fixed shape, this force appears as a force squeezed into the middle. From a shape perspective, it's like inserting an isosceles trapezoid into another hollow that resembles an isosceles trapezoid.
Wedge fittings and wedge sliders are available in metallic and non-metallic versions depending on the cable material. Although wedge-shaped fittings do not have such strict requirements on the diameter of the optical cable, in order to ensure a better use effect, there is still an optimal use range, otherwise the tensile value cannot be maximized.
If the outer diameter of the fiber optic cable does not match the applicable range of the fitting design, the wedge-shaped core slider will expose most of the exterior of the housing, and the stressed portion is only the wedge-shaped part of the core slider contacting the housing. Another advantage of wedge fittings is that they are easy to exit. The wedge slides can be released when force is applied in the opposite direction. If the sag does not fit the span, it can be adjusted and used repeatedly. Compared with pre-twisted fittings, the application characteristics of wedge fittings are:
(1) It is easy to install and disassemble, and can be reused many times;
(2) The construction efficiency is extremely high;
(3) The adaptability of the outer diameter of the optical cable is strong:
(4) The stress distribution on the optical cable is uniform and will not damage the optical cable.
However, the disadvantage of wedge fittings is that the allowable force value cannot be too high, that is, the span between the pylons should not be too large, usually 200 meters or less is suitable.