Agtec Telecoms - Pulled Fibre Cord to Fibre Jointing Procedure

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INTRODUCTION
To enable an 8 or 12 fibre bundle(or multiple 8 & 12 fibre bundles) to be attached to the pull cord incorporated inside the 8/5 tube, a special crimp is required to hold them together tightly during the pulling in of the fibre bundle. The crimps are designed to break at loads of between 5 kg and 6.5kg, which when installing 8 or 12 fibre bundles, acts as a fuse which breaks the joint before the fibre bundles become over-tensioned and risks optical damage.

RECOMMENDED EQUIPMENT & TOOLS
Bootlace Ferrules Un-insulated (1.5mm²) (RS Number :- 211-4280)+ Bootlace Ferrule Crimp tool (Found in the RS Catalogue) Fibre outer sheath stripper (code 7299).

Multiple Fibre Pulling
When installing fibre bundles into 8/5 tubes, up to 3 fibre bundles can be installed in one installation. This is carried out in the same sequence of events as the procedure above, but three fibres are attached to the pulling cord, over a
staggered length. The procedure below gives a step by step method
for connecting multiple fibre bundles to the pulling cord.

2. Slide pull cord through the centre
of the ferrule with the larger end of
the ferrule opposite the pulled fibre
tubing.

4. 12 fibre with outer sheath
removed.

6. Insert the ferrule into the jaw 1 of
the crimping tool (0.5 - 0.75mm²).

8. Remove the ferrule from the
crimping tool. Fibre bundle is now
ready for pulling into tube.

2. Stagger the ferrules along the
pulling cord so that they are 5cm
apart.

4. When pulling in the fibre
bundles, make sure that they enter
the 8/5 tube smoothly. These may
need to be guided in.

1. Choose correct sized ferrule
(1.5mm² for 8 & 12 fibre bundle)

3. Using the fibre outer sheath
stripper (code 7299), remove
around 3cm of outer sheath from
the 12 fibre (not req’d for 8 fibre).

5. Thread the fibre through the
ferrule until flush with the end of the
ferrule.

7. Close down the crimping tool
until fully closed (a ratchet crimping
tool must be used here to ensure
the same force is applied to each
joint).

9. When using 8 fibre bundle. Do
the same as shown but do not
remove the fibre outer sheath
before inserting into ferrule.

1. Insert 2 or 3 ferrules onto the
pulling cord (1 ferrule for each fibre
bundle).

3. Insert the fibres as described
above.

Place the fibre unit between the jaws of the cutter, sitting it in the V-shaped groove.
Hold the cutter stationary in one hand, and with the jaws closed, rotate the fibre a full 360°, ensuring the outer sheath has been completely cut (Fig 3).

The result should be the easy removal of the sheath (Fig 4). If the sheath doesn’t come off, check to see if the cut is completely 360°, or that the cut is not deep enough.
Take care not to cut too deep as this will damage the fibre.
With the outer sheath removed, the end of the fibre bundle needs to be crushed to enable the paring of the fibres. This is done with the end of the fibre strippers as shown in the adjacent photo (Fig 5).
The length of the crushed section needs only to be about 30mm.
Once the end has been crushed, the loose acrylate can be scraped off using the fibre strippers. This will leave the bared individual fibres. Take care not to squeeze the strippers too much as this may break some of the individual fibres (Fig 6).
Hold the individual fibres in two even bundles (this gives maximum strength to the fibres, minimising the risk of a fibre snapping) and pull apart to the desired length (Fig 7).
Greater care must be taken when stripping two and four fibre units.
Once the fibres have been pared back to the required length, carefully separate the fibres from the acrylate, as shown, and snap off the loose acrylate, taking care not to break off a fibre in the process (Fig 8).

The end result is all the fibres free from any acrylate, as shown
on the adjacent photo (Fig 9).