TOP 7 CONSIDERATIONS FOR FIBRE OPTIC CABLE INSTALLATION
With the development and implementation of 5G, optical fibre technology is now seen as the future of connectivity. To keep this connectivity at the speed of light it is important to pay attention to the rules of fibre optic cable installation. Therefore, we have put together a list of seven important factors to consider.
- MINIMUM BEND RADIUS
For fibre optic cable installation maintaining fibre optical cable’s minimum bend radius during installation is a significant factor. In many cases, as compared to the installation of UTP cable in the horizontal or coaxial cable, optical fibre installation is much easier.
Bending the fibre cable tighter than the minimum bend radius may result in increased attenuation and broken fibres. When the bend is relaxed and if the elements of cable are not damaged, the attenuation should turn to normal.
- MAXIMUM TENSILE RATING
During fibre optical cable’s installation maximum tensile rating should not exceed as per the values specified by the manufacturer. When a mechanical pulling device is used tension on the cable should at all times be monitored.
Circuitous pulls can be proficient through the use of back feeding or center pull techniques. For indoor installations, at every third 90° bend, pull boxes can be used to allow cable access for back feeding.
- MAXIMUM VERTICAL RISE
All optical fibre cables have a maximum vertical rise that is a function of the cable’s weight and tensile strength. This represents the maximum vertical distance the cable can be installed without intermediate support points.
Some guidelines for vertical installations include the following:
- All vertical cable must be secured at the top of the run.
- A split mesh grip is recommended to secure the cable.
- The attachment point should be carefully chosen to comply with the cable’s minimum bend radius while holding the cable securely.
- Long vertical cables should be secured when the maximum rise has been reached.
- CABLE PROTECTION
If future cable pulls in the same duct or conduit are a possibility, the use of an inner duct to sectionalize the available duct space is recommended. Without this sectionalization, additional cable pulls can entangle an operating cable and could cause an interruption in service.
- DUCT UTILIZATION
When pulling long lengths of cable through duct or conduit, less than a 50% fill ratio by cross-sectional area is recommended. For example, one cable equates to a 0.71 inch outside diameter cable in a 1 inch inside diameter duct.
Multiple cables can be pulled at once as the tensile load is applied equally to all cable. Fill ratios may dictate higher fibre counts in anticipation of future needs. One sheath can be more densely packed with fibre than multiple cable sheaths.
In short, for customer premises applications, the cost of extra fibres is usually small when these extra fibres are not terminated until needed. For a difficult cable pull, extra fibers installed now but not terminated may be the most cost-effective provision for the future.
- PRECONNECTORIZED FIBER CABLE ASSEMBLIES
The use of factory-terminated cross-connect and interconnect jumper assemblies is acceptable, the use of pre-connectorised backbone and distribution cable presents special installation techniques.
These connectors must be protected when installing the connectorised end of these cables. Protective pulling grips are available to protect connectors, but the grips outside diameter may prevent installation in small inner ducts or conduits. Before ordering factory connectorised cables the size of the pre-connectorised assembly and pulling grip should be considered.
There may also be additional installation requirements imposed on the grip by the manufacturer, in terms of minimum bend radius and tension, which would be the limiting parameters in an installation.
- FIBER OPTIC CABLE SLACK
A small amount of slack cable (20-30 feet) can be useful in the event where cable repair or relocation is needed. The slack can be shifted to the damaged point If a cable is cut, necessitating only one splice point in the permanent repair rather than two splices if an additional length of cable is added. This results in reduced labor and hardware costs and link loss budget saving.
When the drop is finally needed an additional cable slack (approximately 30 feet) stored at planned future cable drop points will result in savings in labor and materials.