Construction of mobile overhead optical cables

Mobile overhead optical cables are installed using structured pole setups, cable types, and tensioning methods to ensure reliable, safe, and rapid deployment.

Key Steps in Construction

1. Pole Selection and Installation Poles are the primary support for overhead optical cables. Standard pole heights range from 7m to 9m depending on terrain and obstacles, with tip diameters around 150mm. Pole depth varies by surface type: 0.9m for rocky terrain and 1.2m for soil. Pole spacing is typically 50m, adjustable to 60m in mountainous areas, and special handling is required for river or road crossings. Poles must be vertical, with corner poles slightly tilted to maintain tension, and backfill should be compacted layer by layer to ensure stability . 2. Cable Types and Support Methods Two main types of overhead optical cables are used:

• Self-supporting cables: High-strength, capable of spanning long distances without additional support, but costly and complex to install.
• Messenger-supported cables: Suspended from a supporting wire, easier to install and maintain, suitable for mobile or temporary setups . Common construction methods include:
• Hanging wire support: Simple and cost-effective, widely used.
• Hanging wire winding: More stable, requires specialized winding equipment.
• Self-supporting method: Rarely used due to high cost and maintenance difficulty . 3. Cable Pulling and Tensioning Before pulling, ensure the pipeline or guide path is clear and clean. Cable lengths should be calculated with extra slack for extension and retraction. Pulling should be done in sections (generally ≤2 km) from the middle outward, with a maximum pulling force of 120 kg. Reinforced core sections should be used for pulling, and waterproofing at cable heads is essential. Guide devices prevent dragging on the ground and reduce friction . 4. Grounding and Safety Metal components of the cable and support structures must be reliably grounded, especially in mountainous or high-voltage areas. Typically, three grounding points per kilometer are recommended. Lightning arresters should be installed when crossing power lines . 5. Environmental and Technical Considerations Overhead cables must withstand wind, ice, and temperature fluctuations (-40°C to +80°C). Minimum tensile strength ranges from 1,500N for short spans to 12,000N for long-distance ADSS cables. Bend radius should be at least 20 times the cable diameter to prevent microbending losses . 6. Maintenance and Monitoring Regular inspection of pole alignment, cable tension, and grounding is essential. Mobile overhead setups may require temporary supports or adjustments to accommodate terrain changes or seasonal conditions. Using modular closures and splice trays allows for easy maintenance and fiber management .

Summary

Mobile overhead optical cable construction involves careful pole selection, cable type choice, tensioning, grounding, and environmental adaptation. By following structured installation methods and safety protocols, deployment can be rapid, cost-effective, and reliable, even in challenging terrains or temporary setups. Proper planning ensures minimal strain on fibers, long-term durability, and compliance with industry standards .