Installation Guidelines for Copper and Fibre Data Cabling

During the installation of either structured cabling Cat5e / Cat6 or Cat6a cable and Single Mode and Multi Mode Fibre Optic Cabling several considerations should be met during the installation and termination of these cables

Data Cabling Guidelines

1. Depending on the length of the data cable being installed there will be a maximum distance that cable can be installed to retain the performance designed for that data cable
2. Pulling Tension and Bend Radius. Maintaining these avoids a decrease in performance on the cable when used in a structured cabling system
3. Cable termination. If the cable isn’t terminated correct then the performance of the links will be less than optimum or even unsuitable for running data over
4. Maintaining a consistent standard throughout the link. The weakest part of the links is the overall performance for that link

The first consideration is whether the cable link will be a permanent link from patch panel to user outlet in one cable run or via a consolidation point. (an area where a cable is terminated and then extended further to the desk area. This set up is called a channel link

Each termination in a link and the introduction of patch leads into a link  reduces the overall length that the data cabling links can support

• Cabling Lengths

Copper Data Cabling

Based on an Ethernet data cabling link

Regardless of data cabling class (cat5e / cat6 / cat6a) all copper cabling standards for a permanent link are set at a maximum length of either

1. 100m for a direct link switch to PC / Telephone / switch
2. 90m for a permanent link with an allowance of 5m patch leads at each end

This applies for unshielded and shielded cabling types

Applications such as ADSL / VDSL / Analog Phone can run longer distances as per separate documentation

Fibre Optic Data Cabling

In contrast to copper data cabling the maximum lengths associated with fibre optic cabling are the distance the cable can be installed to support a certain performance over that distance with that cable. I.e 1gig / 10gig etc

The following chart shows the maximum distance for fibre optic distances in association with the performance speeds

• Pulling Tension and Bend Radius

When installing both fibre optic cabling and copper cabling how the cable is pulled and how it is installed especially in how it bends around corners and through spaces will have an effect on the performance of the final installed cable.

The following standards are required when installing both these types of cables

Copper Data Cabling

The maximum pulling tension for installing a cat5e / cat6 / cat6a or other 4 pair copper cable is 100N or 25pound force during installation

The minimum inside bend radius should be a maximum four times the diameter of the installed cable. Higher specified cables will have a larger diameter and therefore require a higher allowance of bend radius

Fibre Optic Cabling

The pulling tension for fibre optic cabling should follow the following guidelines

Inside fibre cable with 4 or less fibres                                      220N / 50lbsf

Inside / outdoor fibre cable upto 12 fibres                             1335N / 330lbf

Inside / outdoor fibre cable over 12 fibres                             2670N / 600lbf

For bend radius the following maximum bend radius should be maintained for all fibre optic cables

During installation / under load                                                 20 x the outside cable diameter

After installation / no load                                                         10 x the outside cable diameter

• Cable Termination

The requirement when terminating copper data cables is to terminate with the minimum of untwist in the 4 pairs of transmission cores. If the cores are untwisted too much then the performance is harmed and transmission performance reduces

The following are the maximum recommended pair untwists for different categories of copper cabling

Termination of fibre optic cabling will depend on the termination method chosen. Termination methods can include

1. Splicing
2. Polishing
3. Crimp

Termination practices will depend on manufacturer recommendations particular to their product

• Consistent products throughout the link

The performance of the overall link is only as good as the weakest part of the overall link.

Therefore for a cat6a link every component needs to be of a cat6a product.

This includes

• Patch Panel
• Cable
• Module / jack
• Patch leads

If any of the above elements are not of the same standard then the overall link its reduced to the lowest denominator. I.e. a cat5e patch leads in a cat6a termination will render the overall performance to a cat5e system as per the limitations in the tables above

As a final note keeping a shielded link consistent will also have the same effect by using non shielded components in a shielded cabling link

Structured cabling Cat5e / Cat6 or Cat6a cable and Single Mode and Multi Mode Fibre Optic Cabling