Let us first begin this blog by offering a quick disclaimer—we love our brothers and sisters who work tirelessly as Electricians. However, there is a fact about their profession that must not be ignored and that is that they are not trained nor certified to handle network infrastructure installations.
Ultimately, because they do not have a background in the proper installation of network cabling, quite often these professionals can damage the cabling to a point where it does not function and cannot be used. And the results in this sort of situation are significant; as the customer, you will experience additional costs for replacing the damaged cabling along with production downtime, failed inspections, and significant delays to project schedules. Even simple things such as improper labeling at each end of a cable can cause unnecessary and additional labor in order to correct it. What this means is that costs have the potential to grow exponentially as each mislabeled cable will need to be toned and traced to verify it from end to end.
Below we have included a good example of a mislabeled cabling and the confusion it can cause.
Category Cable & Fiber Optic Cable
Both of these cables have very low tensile strength, and they can be easily stretched or broken. This will typically occur when the cables are pulled around sharp bends where there is more pressure present than what the manufacturer’s specifications allow.
When the Category cable is stretched too thin, it will lose transmission rates as the surface area has changed. This is because of the fact that 80% of electrical flow on copper cabling occurs at the outer surface of the conductor. Here is a picture of the damage caused when too much pressure is applied when the cable is pulled.
Now, when fiber optic cables are stretched too thin, the light wave traveling through the fiber optic strand begins to bounce off of the inner walls at a different frequency. This changes the shape of the light’s wavelength. What this leads to is refraction issues, high dB loss, and backscatter issues. It can also lead to challenges when syncing the light transmission at either end of the fiber optic cable.
Remain Aware of These Issues
Network cabling jackets are also not as durable as typical electrical cable such as THHN, THWN, XHHW, SOJW, etc. The outer jacket of Category cabling, (CM, CMR, CMP, etc.) can be destroyed quite easily by causing excessive friction on the cable jacket when pulling the cable. In the case of Category cabling that is listed as Unshielded Twisted Pair (UTP), the paired conductors inside of the cabling can be exposed, resulting in damage to them as well as possible issues with induced noise from other magnetic fields generated by other cables.
Now, in the case of Category cable that is listed as Foil Twisted Pair (FTP) or Shielded Twisted Pair (STP), the outer jacket and the foil or shield can be damaged. The results can lead to grounding issues that are used to protect the cable and the transmissions over the cables, which causes equipment to not function properly. Additionally, this can result in induced noise from other magnetic fields generated by other cables.
Here is a picture of jacket damage caused by excessive friction while pulling the cable.
Other Pertinent Facts to Keep in Mind
Category cable has a length limit of 325 ft. or 100 meters. This includes the permanent link (i.e. the cable that is run from the patch panel to the device outlet) and the channel adaptors (i.e. the patch cable that is installed from the network switch to the patch panel at the head end and the patch cable installed from the device outlet to the workstation).
EIA/TIA/BICSI standard and manufacturer specifications limit the permanent link to no more than 295 ft., leaving 15 ft. for the channel adaptor at the head end and 15 ft. for the channel adaptor at the workstation location. If the limitations on length are not followed, the cable will not transmit data or power for PoE devices correctly. In turn, you will experience slower transmission speeds, loss of power for PoE devices, and can even lose additional bandwidth caused by excessive traffic because the network switch is trying to sync with the workstation or network device at the other end of the cable.
Keeping to Code
Category cabling and fiber optic cabling fall into Chapter 8 of the NEC code book for Communications systems. Within that chapter, all of the requirements are listed for acceptable installation of all communications cabling. This includes separation requirements from other cables carrying power or lighting and separation of cabling in raceway systems from other cables carrying power or lighting.
However, remain aware that the requirements for acceptable means of supporting and securing cabling are often referenced in Chapter 3 on Wiring Methods and Materials. Communication cable should be supported and secured horizontally every four to five feet, and up to every 10 ft. vertically. The exception is if the environment does not allow for any acceptable means of supporting and securing.
Here is a picture of unacceptable support and securing—as well as one that does not maintain separation distances from power and lighting cables as required by NEC code.
For more information about how to ensure your Category cabling or fiber optic cabling project can go according to plan—and be installed by professionals who have the necessary training and certification for handling and installing these materials, reach out to Connectivity.