Methods for laying aerial optical cables in Sierra Leone

Aerial optical cables in Sierra Leone can be installed using self-supporting ADSS cables, figure-8 cables, or lashed cables, following careful planning, safety protocols, and proper pole and route preparation.

Planning and Preparation

Before installation, a detailed survey of the route is essential, including ground conditions, existing poles, and potential obstructions such as trees, roads, and power lines . Permits from local authorities and coordination with traffic and utility agencies are required. Splice points and slack storage locations must be pre-determined, ensuring accessibility for maintenance and installation vehicles .

Types of Aerial Optical Cables

• All-Dielectric Self-Supporting (ADSS) cables: Lightweight, non-metallic, can be installed near power lines without interference .
• Figure-8 cables: Include an independent catenary wire for support, suitable for longer spans .
• Lashed cables: Fiber cables can be lashed to existing overhead cables or messenger strands, reducing the need for new support structures .

Installation Methods

1. Moving Reel Method: The cable is pulled from a moving reel along the pole line, suitable for continuous runs .
2. Stationary Reel Method: The reel remains fixed while the cable is pulled along the route, often used in urban areas .
3. Cable Lashing: The fiber cable is lashed to a pre-installed messenger strand, maintaining proper tension and sag to withstand environmental loads like wind or rain .
4. Micro-Duct Jetting: For micro-duct cables, blowing or jetting the cable through ducts can be used in aerial applications where ducts are pre-installed .

Pole and Span Considerations

• Pole spacing typically ranges from 25–40 meters in urban areas, 40–50 meters in suburban areas, and up to 67 meters in rural areas .
• Galvanized steel strands (e.g., 7/2.2 mm) are commonly used as suspension wires for standard aerial fiber, with armored cables requiring slightly stronger strands .
• Dead-end poles and guying may be necessary to handle tension and unbalanced loads during installation .

Safety Measures

Aerial installation involves working at heights and near electrical lines. Key safety practices include:

• Use of personal protective equipment: hard hats, gloves, steel-toed boots, long-sleeve clothing, and safety harnesses .
• Maintaining three-point contact on ladders or poles.
• Proper ladder positioning and securing.
• Ensuring all personnel are trained in aerial cable handling and climbing techniques .

Cable Handling and Protection

• Avoid bending cables below the minimum bend radius and prevent twisting or excessive tension .
• Use carbon-black polyethylene jackets for UV protection in outdoor environments .
• Leave cable reserves in loops or figure-eight shapes for future maintenance .
• Splice closures and protectors should be installed at designated points to ensure fiber integrity .

Environmental and Regulatory Considerations

• Respect local regulations regarding pole usage, right-of-way, and environmental protection .
• Plan for weather conditions, such as heavy rain or wind, which may affect sag and tension.
• Ensure proper signage and work area demarcation during installation . By following these methods, aerial optical cable deployment in Sierra Leone can be efficient, safe, and durable, providing reliable telecommunications infrastructure across urban and rural areas .