Construction process for laying overhead optical cables

The construction of overhead optical cables involves a systematic sequence of pole selection, installation, cable pulling, and grounding to ensure safe and reliable fiber deployment.

Step 1: Pole Selection and Preparation

• Choose the type of pole based on terrain and obstacles. Standard poles are typically 7 meters high with a tip diameter of 150 mm, while special sections may require 8–9 meters .
• Determine pole depth: 0.9 m for rocky surfaces, 1.2 m for other soils .
• Set pole spacing: Standard distance is 50 m, adjustable to 60 m in mountainous areas .
• Mark pole numbers for identification, ensuring visibility and proper orientation .

Step 2: Pole Installation

• Excavate and check hole depth before erecting poles .
• Ensure vertical alignment: Straight-line poles should have less than 5 cm deviation; corner poles require slight inward adjustment and tip tilting toward tension wires .
• Install anchors and guy wires: Anchor depth must be verified, with distance-to-height ratios maintained for stability .

Step 3: Cable Laying Preparation

• Select the construction method: Hanging wire support, hanging wire winding, or self-supporting methods, depending on terrain and line requirements .
• Install guide devices at lead-in and exit points to prevent cable dragging and reduce friction .
• Reserve cable length for extension and retraction, typically limiting each pull to around 2 km .

Step 4: Cable Pulling

• Pull the cable carefully along the prepared route, ensuring the pulling force does not exceed 120 kg .
• Use reinforced core sections for pulling and apply waterproof reinforcement at cable heads .
• Maintain proper bending radius: Cable turns should exceed 20 times the cable diameter to prevent damage .

Step 5: Cable Fixing and Anchoring

• Secure the cable to poles using clamps or hooks according to the chosen method .
• Ensure tensioning is uniform to prevent sagging or excessive strain .
• Install joint boxes or closures for splicing, ensuring proper sealing and anchoring .

Step 6: Grounding and Safety

• Ground all metal components reliably, especially in high-voltage or mountainous areas, typically with three grounding points per kilometer .
• Install lightning arresters when crossing power lines .

Step 7: Inspection and Testing

• Check alignment, tension, and grounding for compliance with design standards .
• Perform optical tests to verify signal integrity and ensure no fiber strain occurred during installation .

Step 8: Finalization

• Backfill and compact around pole bases, flush with urban surfaces or slightly higher in suburban areas .
• Document the installation with pole numbers, cable routes, and test results for future maintenance . Following this sequence ensures that overhead optical cables are installed safely, maintain signal integrity, and comply with engineering standards.