How to lay optical fiber cables on steel wires

Fiber optic cables are typically attached to steel wires using a messenger strand and lashing wire system, ensuring mechanical support and proper tension management.

Understanding the Components

Steel Messenger Strand: A stranded steel cable that supports the weight of the fiber optic cable. It is usually made of carbon steel with a zinc or zinc-aluminum coating for corrosion resistance. The strand consists of six wires wrapped around a central wire and comes in various diameters and strengths depending on the installation environment . Lashing Wire: Stainless steel wire, typically 0.038" to 0.045" in diameter, used to secure the fiber cable to the messenger strand. It is annealed for high ductility and selected based on the cable weight and environmental conditions .

Installation Steps

1. Preparation:
   • Inspect the fiber optic cable and steel messenger strand for damage.
   • Ensure all tools are ready, including tension machines, pulleys, and lashing equipment .
2. Positioning the Messenger Strand:
   • Install the steel messenger strand along the intended aerial path.
   • Maintain proper tension to prevent sagging and allow for environmental factors like wind or ice .
3. Attaching the Fiber Cable:
   • Place the fiber optic cable along the messenger strand.
   • Use the lashing wire to wrap the fiber cable around the messenger strand at regular intervals. The lashing should be tight enough to secure the cable but not so tight as to damage the fiber .
4. Tension Management:
   • Use a tension machine to maintain the correct tension on both the messenger strand and the fiber cable during installation.
   • Ensure the cable is not overstressed, which could lead to signal loss or mechanical failure .
5. Testing and Inspection:
   • After installation, inspect the lashing for uniformity and secure attachment.
   • Test the fiber optic cable using an optical power meter or visual fault locator to ensure minimal signal loss .

Additional Considerations

• Environmental Protection: Choose messenger strand coatings (zinc or zinc-aluminum) based on exposure to coastal or corrosive environments .
• Slack Management: Provide slack loops at intervals to accommodate thermal expansion and future maintenance .
• OPGW Specifics: For OPGW, the fiber is integrated within the steel wire itself, and installation follows similar tension and support principles, often atop power line towers . By following these steps, fiber optic cables can be securely and efficiently connected to steel wires, ensuring long-term reliability and minimal signal degradation.