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Fibre Tranching





We use a two of methods of fibre tranching and will choose the best option for each property. This does mean that typically no two fibre tranching are the same so we agree the install plan with you before starting work.


Ducting & Trenching


The traditional method of laying optical fibers still used in most developing countries is Ducting and Trenching. This involves creating a trench through manual or mechanized soil excavation. This approach is preferred in countries where manual labor is cheap.

Figure 1: Cable ducts in open trench

Trench specifications are normally defined by local authorities and could be specified for each operator in countries with multiple operators.

The trenching process needs careful control to make sure the trench floor does not have any kinks and is uniform, and trenches do not have major bends.

Ducts are placed in the trenches and fiber is then blown through the ducts with specialized fiber blowers, using water or air. In Air Assisted Fiber Blowing, the blowers use compressed air to push fiber through ducts.

It is standard practice to lay conduits, then draw inner ducts through the conduits and finally blow the fibers through the ducts. A common conduit size is 4 inches (100mm), but 6 inch (150mm) conduits are also available. The size of the inner duct is normally 1.25 inches.


Mini Trenching


Mechanized equipment is used to create mini trenches in many different surfaces. This technique can be used on routes that contain asphalt surfaces such as sidewalks and roads. The technique is however not suitable for soil with cobbles or gravel, or sandy soil. This technique has an advantage over conventional cable laying methods in that it is much faster to execute. The cross-section and depth of the trench will depend on the number of ducts to be laid.  While the cross-section varies between 7 and 15 cm, the depth is typically between 30 and 40 cm.