Wuxi Dingrong Composite Material Technology Co. Ltd
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January 12, 2026
FRP strength members for optical cables.
This is a critical component that significantly impacts the cable's performance and reliability.
FRP stands for Fiber Reinforced Plastic/Polymer. In optical cables, it is typically a straight, rigid rod placed in the cable core.
High Tensile Strength, Light Weight:
This is its core advantage. FRP is made of high-strength glass fibers embedded in a resin matrix, offering extremely high tensile strength (often much higher than steel wire of equivalent weight). It effectively protects delicate optical fibers from excessive stretching during installation and operation.
It is much lighter than traditional steel wire strength members, facilitating transportation and installation.
Non-Metallic, All-Dielectric:
FRP is an insulating material, making the cable an all-dielectric cable.
Advantages:
Lightning Protection: Lightning strikes cannot be conducted through the strength member, making it ideal for overhead installation in lightning-prone areas.
Electromagnetic Interference (EMI) Immunity: It is unaffected by electromagnetic fields and does not induce currents. Suitable for use near power lines (e.g., OPGW, ADSS cables) or in electromagnetically sensitive environments.
No Electrochemical Corrosion: Unlike metal strength members, it does not corrode in humid or chemical environments, ensuring a longer service life.
Good Thermal Stability:
Has a very low coefficient of thermal expansion. Its dimensions remain stable with temperature changes, preventing additional stress on fibers due to thermal expansion/contraction and helping maintain stable optical performance.
Moderate Flexibility:
Offers sufficient flexibility for cable bending and coiling while providing adequate rigidity to resist crushing.
Central Strength Member: The most common form. Located at the cable center, with fibers stranded around it or placed in surrounding loose tubes.
Side Strength Members: In some flat or ribbon cables, they may be placed on the sides.
GFRP: Glass Fiber Reinforced Plastic, the most commonly used type.
KFRP: Aramid Fiber Reinforced Plastic, offers higher strength for specialized applications requiring extreme tensile strength (e.g., submarine cables).
| Characteristic | FRP Strength Member | Steel Wire Strength Member |
|---|---|---|
| Weight | Light | Heavy |
| Tensile Strength/Weight Ratio | High | Lower |
| Electrical Conductivity | Insulating, All-Dielectric | Conductive |
| Lightning/Corrosion Resistance | Excellent | Requires special treatment (e.g., galvanization) |
| Bending Fatigue Resistance | Good | Excellent (High Flexibility) |
| Cost | Typically Higher | Typically Lower |
ADSS Cables: All-Dielectric Self-Supporting cables, which must use FRP as the load-bearing component.
OPGW Cables: Optical Ground Wire, which may also incorporate FRP units.
Indoor/Building Cables: Where lightweight, flexible, and safe (non-metallic) properties are required.
Overhead Lines with High Lightning Protection Requirements.
Environments with Strong Electromagnetic Interference: Such as power systems and railways.
Weight-Sensitive Applications: Like long-span overhead cables or lightweight military cables.
In summary, the FRP strength member is a significant innovation in modern optical cable technology. By providing high-strength, lightweight, and insulating support, it enables optical cables to adapt to more complex and demanding physical and electrical environments, particularly in applications requiring "all-dielectric" properties.
