Release date : 2022/1/11 10:59:10
No new installation methods are detailed in AN/NZS 3080, TIA or ISO's six categories of specifications. The installation methods specified for Category 5 cabling a few years ago also apply to Category 6 cabling. The difference is that because Category 6 has very strict performance standards, it requires a higher quality of installation. Any installation error or shortcut in Category 6 cabling can result in a pass/fail test. Like most responsible manufacturers, Molex Enterprise Cabling Networks strongly recommends strict adherence to the installation methods specified in the Cabling Standards document and the recommended practices we provide with our products. Molex Enterprise Cabling Networks has for many years dictated that certified installers must employ quality installation methods, as product and installation have the same impact on the overall quality of the cabling system.
Some important issues to consider during installation include:
1. cable tension
Do not exceed the cable pull tension specified by the cable manufacturer. Excessive tension will deform the pair lay in the cable, seriously affect the cable's ability to suppress noise (NEXT, FEXT and derivatives), and seriously affect the cable's structural return loss, which will change the cable's impedance and damage the overall return. wave loss performance. These factors are important factors in the transmission of high-speed local area network systems, such as Gigabit Ethernet. Also, this can cause the pairs to unravel, potentially damaging the wires.
2. Cable bend radius
Avoid excessive bending of the cable as this will change the lay length of the pairs in the cable. If bent excessively, the wire pairs may spread apart, resulting in impedance mismatch and unacceptable return loss performance. Additionally, this may change the relationship between the 4-pair lay lengths within the cable, causing noise suppression issues. Each cable manufacturer recommends that the cable bend radius be no less than 8 times the installed cable diameter. For a typical Category 6 cable, the bend radius should be greater than 50 mm. One of the most critical areas of the problem is the wiring closet, because the large number of cables entering the patch panel can cause some cables to be over-stressed and over-bent in order to keep the wiring clean. Often invisible, even the most dedicated installer can inadvertently degrade the performance of a cabling system. If the manufacturer provides rear cable management devices, be sure to use these devices in accordance with the manufacturer's recommendations. However, the cable bend radius inside the device has different (more stringent) restrictions. In general, the cable bend radius during installation is 8 times the cable diameter. In practice, the bend radius in the back box is 50mm and the minimum bend radius for incoming cable ducts is 100mm. For buildings where smaller diameter cables were originally installed/specified, this has a significant impact on reusing legacy device systems inside the building.
3. cable compression
Avoid over-tightening the cable ties and compress the cables. This problem is most likely to occur in large bundles of cables or cable installations, where the cables on the outside of the bundle will experience more stress than the cables on the inside. If the cable is too tight, the stranded wires inside the cable will be deformed, affecting its performance, and generally making the return loss more obviously unqualified. The effects of return loss accumulate, and each overtight cable tie pair increases the total loss. Worst-case conceivable is the use of cable ties every 300mm in long run cables hanging from dangling wires. If the cable hanging on the hanging wire is 40 meters long, the number of cable ties is 134 times. When using cable ties, pay special attention to the amount of pressure applied to the tie. The cable ties are strong enough to support bundles of cables.
A better approach is to ensure that there is no deformation of the cable jacket when tying the cables together using cable tie pairs. This is also very important in wiring closets where the user typically tightens the cable ties to keep the cables clean, or where it is difficult to access the termination points on the back of the panel. We recommend using hooks and looped cable ties, such as Velcro brand ties. These devices make it impossible to damage cables due to compression, and they are also easier to remove. This makes it easy to add more cables to the bundle, but at the same time they make it easier for unauthorized persons to modify the wiring.
4. Cable weight
Note that a meter of 24 Category 6 cables weighs close to 1.0kg, while the same amount of Category 5 or Category 5e cables weighs only 0.6kg. The weight of the cable must be considered when using the suspension wire to support the cable. It is recommended that each suspension wire support point support a maximum of 24 cables per bundle.
5. cable knot
When pulling the cable from the spool, be aware that the cable can sometimes get tangled. If the cable is kinked, it should be considered damaged and the cable should be replaced. Installation pressure can cause installers to straighten cable knots. However, the damage has occurred and this will be discovered when the cable is tested. Remember, all of these effects add up, and while it is unlikely that a single cable knot will fail the test, this effect combined with the performance degradation caused by cable ties and the reduced margin for Category 6 cabling will cause the test to fail.
6. Number of cables in bundle
When any number of cables are bundled together in very long parallel lengths, the pair capacitive coupling (eg blue pair to blue pair) of different cables in a bundle of cables with the same lay length can result in a significant increase in crosstalk. This is called "alien crosstalk", and this metric has yet to be specified or precisely defined by a cabling standard. The best way to eliminate the adverse effects of alien crosstalk is to minimize the length of long parallel cables and install bundles of cables in a pseudo-random fashion. Historically, we have used "comb" routing in our traces to keep things clean. Bundling the cables together is the best way to avoid any two pairs of different cables that might run in parallel for the effective length. There are no shortcuts or other efficient ways to do this but it should be noted that long parallel lengths of cable may lead to potential alien crosstalk.
7. Cable jacket stripped
At the cable termination point, the exposed wire pairs from the sheath to the IDC after termination must be kept to a minimum. It's not absolutely necessary to strip the cable jacket, it's just a way to comfortably attach the wires to the IDC. TIA or ISO wiring standards specify the length of the stripped jacket. By minimizing the length of the jacket to be stripped, this ensures that the pair lay distance inside the cable can be maintained for the most efficient transmission path. Excessive jacket stripping on the IDC will compromise the NEXT and FEXT performance of the Category 6 cabling system.
8. Pairs spread out
At the cable termination point, the lay length of each pair in the cable should be as close as possible to the IDC. The pair lay length is calculated by the cable manufacturer, and changing the cable lay length will adversely affect the cable performance. Although the ISO and TIA cabling standards for Category 5e specify the length (13 mm) at which pairs are spread apart, they do not do so for Category 6 cabling. The current recommendation is to follow the recommendations provided by the manufacturer. At termination points where the contact and loop conductors are out of sequence, it is better to add a pair of wires than remove a pair to ensure alignment with the associated IDC. This ensures that the pair lay distance within the cable can be maintained for the best possible transmission path. Excessive spread of IDC on-line pairs will impair the NEXT, FEXT and return loss performance of the Category 6 cabling system.
9. ambient temperature
The TIA and ISO standards conferences have raised the profile of this environmental issue. Of course it has caused problems in Category 5 and 5e in the past, and the industry believes that in Category 6 cabling it is a much more important issue. The temperature of the environment in which the cable is installed does affect the transmission characteristics of the cable. If possible, avoid high temperature environments that may be encountered, eg >60°C. This can easily happen if the roof over the ceiling is exposed to direct sunlight. Generally speaking, the attenuation of the cable increases as the temperature increases. The effect on long links is that it can result in either a narrow pass or fail for this parameter.
Summarize
As you can see, in the installation parameters, there are no new major changes in Category 6 wiring compared to Category 5e wiring. To minimize the difficulty of installing a Category 6 system, it is important not to over-strengthen adhere to existing installation guidelines.
