When it comes to Fibre to the Home (FTTH) installations, fibreDUCTTM MicroDuct and MultiDuct are a common choice to protect Fibre Optic Cables. This document offers best practice advice on installing buried fibreDUCTTM MicroDuct and MultiDuct to help deliver faster, more effective deployments.

Correct Handling Procedures

  • fibreDUCTTM products are shipped on reels or bobbins.
  • Reels must be lifted by supporting the flanges or sides of the reel.
  • The reel must be unwound in a straight line to ensure the fibreDUCTTM does not tangle.
  • Controlled pace must be used when unwinding to ensure the fibreDUCTTM does not tangle.
  • Tangling will lead to a kink which should be cut at that point and discarded.

Methods of Installation

There are four ways of installing direct buried fibreDUCTTM:

  • In the ground by machine or hand excavating
  • In a micro or slot-cut trench
  • Using a mole plough
  • Inside an existing large diameter duct

For each of these, you should take a number of key steps ahead of installation:

  1. Make sure that fibreDUCTTM is inspected on the reel before and during the unwinding process.
  2. All flaws or faults must be reported immediately to the manufacturer.
  3. Always cut the fibreDUCTTM with a fit for purpose tube cutter.
  4. Make sure that the sealing plug is in place at the ends of the duct.

Best Practice for Direct In-Ground (DIG) Installations

Essentially this involves excavating a trench by hand or by machine, and then installing the fibreDUCTTM directly in the ground before replacing the subsoil and surface. Follow these best practices to achieve an efficient and long-lasting installation:

  • Bury Duct deep enough in the ground to prevent it being damaged.
  • Ensure the bottom of the trench is level so that the Duct lies flat.
  • Avoid sharp bends in the Duct to make Fibre Optic Cable installation easier.
  • Layer of clean fill in the bottom of the trench before installing the Duct.
  • Backfill above and to the side of the Duct with sifted soil to remove damage causing objects.
  • When installing an access box support the Duct to maintain its alignment.

Best Practice for Micro Trenching Installations

Micro Trenches (or Slot Trenches) are cut into hard surfaces, such as roads and footpaths. fibreDUCTTM is then installed at the bottom of the shallow narrow trench, which may wary in width. Follow these best practices when Micro Trenching:

  • Ensure the bottom of the trench is level so that the fibreDUCTTM lies flat.
  • The bottom and sides of the Slot Trench must be dry and clear of debris.
  • Avoid sharp bends in the duct to make Fibre Optic Cable installation simpler.
  • Install stone free bedding in trench before installing the fibreDUCTTM to prevent damage by stones.
  • Backfill above the fibreDUCTTM to prevent damage. Reinstate surface after compacting.

Best Practice for Mole Plough Installations

Used on a tractor or excavator a mole plough cuts a slot similar to a farmer’s plough, with the FibreDuctTM fed along its back edge and drawn into the hole made in the ground by the tip of the plough. There are two types of ploughs – vibrating and non-vibrating. The vibrating plough is used where there are roots or small stones in ground because it cuts through the roots and pushes stones out of the way. Follow these best practices when mole ploughing:

  • Ensure the ground is even as the mole plough follows the ground contours.
  • Bends in the route must be smooth and wide.
  • Mole plough only where there are no hard surfaces and there are unlikely to be other services.
  • Choose a machine suitable for the type of ground.
  • If tree roots or small stones are present use a vibrating plough
  • Choose a machine that carries the FibreDuctTM with to prevent stretching.

Best Practice for Duct in Pipe or Sub-Duct Installations

When installing fibreDUCTTM in larger pipes or Sub-Ducts follow these best practices to achieve optimum results:

  • Calculate if there is sufficient space in the pipe or Sub-Duct.
  • Allow an extra length of duct to compensate for the stretching that happens as the fibreDUCTTM is drawn into the Duct.
  • Allow for expansion of the fibreDUCTTM if air temperatures or storage temperatures are high.
  • When using a winch to pull in the fibreDUCTTM do not exceed the maximum pulling force by using a mechanical fuse. A fuse is not required if pulling in the fibreDUCTTM by hand.
  • Always use a swivel to prevent the fibreDUCTTM twisting as it is pulled into the pipe or Sub-Duct.
  • Always use a pulling sock to distribute the pulling force over the first part of the fibreDUCTTM. Allow 24 hours to pass before restraining the fibreDUCTTM to allow it to reach the same temperature as the Duct and jointing chamber.

FibreDUCTTM is a key part of many Fibre deployment processes. However, as with any type of installation, things can go wrong adding to time and cost. Therefore, following best practice and using high quality equipment is critical to ensuring successful deployments, time after time.