Laying optical cables on existing overhead optical cables

Laying overhead optical cables involves careful planning, pole selection, cable handling, tension control, and post-installation inspection to ensure reliable performance.

Step 1: Planning and Preparation

Before installation, conduct a site survey to determine the route, pole locations, and environmental conditions. Identify obstacles such as roads, rivers, or railways, and plan for appropriate pole heights and spacing. Ensure all necessary permits and authorizations are obtained from local authorities and utility companies . Prepare the required materials, machinery, and human resources for the project .

Step 2: Pole Selection and Installation

Choose poles based on terrain and load requirements. Standard pole heights range from 7m to 9m, with tip diameters around 150mm. For rocky surfaces, dig to 0.9m; for soil, 1.2m . Install poles vertically, ensuring minimal deviation (less than 5 cm) along the route. Corner poles and terminal poles should be positioned and tilted correctly to maintain tension and alignment .

Step 3: Determine Pole Spacing

Typical pole spacing is 50m, adjustable up to 60m in mountainous areas. Urban areas may require closer spacing (25–40m), while rural areas can use 40–50m spacing . Reinforced poles may be needed in extreme environments.

Step 4: Cable Handling and Preparation

Use proper cable handling techniques to prevent damage. Avoid twisting, pinching, or exceeding the bend radius. For long runs, lay the cable in a figure-8 pattern to prevent twists. Use pulling grips and lubricants compatible with the cable jacket, and monitor tension to avoid exceeding maximum tensile loads .

Step 5: Cable Installation

Install the cable using either moving reel or stationary reel methods. Maintain the recommended bend radius using cable guides and ensure a straight pull. For spans over 100m, consider automated pullers with tension control . Secure the cable to poles using messenger wires or self-supporting methods, depending on the cable type .

Step 6: Splicing and Connections

Perform splicing and connectorization according to manufacturer specifications. Protect connectors from contamination and scratches. Ensure the total attenuation budget is maintained when joining cables .

Step 7: Post-Installation Inspection

Check the entire installation for proper tension, alignment, and verticality of poles. Verify that the cable is free from twists, kinks, or excessive bending. Conduct optical tests to confirm signal integrity and document the installation for future maintenance .

Step 8: Safety and Environmental Measures

Implement a safety plan including signage, work area demarcation, and protective equipment. Consider environmental factors such as wind, ice, and temperature fluctuations, and ensure the cable is rated for outdoor conditions (-40°C to +80°C), . By following these steps, overhead optical cables can be installed efficiently, safely, and with long-term reliability.