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Although probably viewed as a simple process to manage, patch cords have the potential to be the weakest link in twisted pair and fiber optic network infrastructures. It is essential to follow correct procedures in administration of twisted pair and fiber optic patch cords to achieve optimum performance and reliability. Applying best practice at every stage will also minimize costs related to moves, adds and changes (MACs).
Best practice in managing patch cords can be divided into four parts:
The Change Request
The starting point for all MACs is the change request. The process for raising and recording the request must be simple, efficient and rigidly enforced. Fundamental to this is designing a plain, simple change request process.
Whether the process is paper-based or electronic, such as using an Automated Infrastructure Management (AIM) system, time spent on designing it to capture all the necessary information and minimize risk errors is a good investment.
Key information includes: names of staff making and authorizing requests, date, unique identifier number, services involved, work required and location of connections.
Searching the Records
Once a request is received, search the records to be sure of the circuit path. Any changes or additions made since your cabling infrastructure was installed should also have been documented.
Check Design Guidelines and Match Cords
Make sure you know the specifications (i.e., Category 5, 5e, 6 or 6A) and design of your cabling infrastructure, because the use of lower performing copper patch cords will have the effect of limiting end-to-end performance. Maximum end-to-end channel performance is only possible when the cord is matched to the rest of the cabling link.
Routing, Patch Cord Lengths and Density
For efficient routing and to establish the correct cord length, first find the best route between the ports to be connected. This is usually the shortest route through horizontal and vertical cable management that does not obstruct or interfere with other cords and connectors in the panel. Avoid routing cords through cable pathways that are already congested.
Having established the best route for the cord, find the minimum required length by adding the horizontal and vertical distances. When selecting a cord, to make a cross connection, avoid excessive slack and provide a neat appearance. Tight cords will pull on connectors and too much slack complicates patch cord management, making the panel harder to work on.
Take care not to mix up cords of different cabling categories. Patch cords may be mechanically compatible across old and new cabling but, in any circuit, the component with the lowest specifications will determine end-to-end performance. For instance, when a Category 5e/Class D cord is used to connect Category 6/Class E cabling, the channel will only deliver Category 5e/Class D performance in accordance with TIA and ISO/IEC standards.
To minimize disconnect time, do as much preparation as possible before performing administrative activities. Study administration records and locate the ports that must be connected or reconnected. Ensure technicians have all the information they need, including the labeling information for the ports involved. An AIM system will automate much of this process, and alleviate potential for human error.
It is essential to ensure cords are of the right type and quality, and that they are clean and in good condition especially when re-using patch cords. Patch cords should be inspected for physical damage including:
- Stress marks from bending on the sheath
- Conductors removed from the plug
- Pin contamination on plug end
- Bent or missing pins on plug end
Once work on a panel is started, it should be completed without delay using best practice at each stage. Cord handling is important. Kinks, snags, pinches and poor contacts can dramatically reduce the performance of a patch cord. The following factors are important in avoiding these problems.
The minimum bend radius specified by standards is four times the diameter of solid conductor cable under no-load. Stranded conductor cords allow tighter radius. Refer to manufacturer’s specifications. Anything less may change the relative position of conductors to the point where transmission performance is reduced.
Cord Pulling and Stress
Be careful not to use excessive force during the patching process. This can stress cords and connectors, reducing their performance. If you need to use force in pulling a cord, something is wrong. Find the problem and fix it before proceeding.
Bundling and tying cords gives the panel a neat appearance but tight bundling increases the risk of crosstalk. Take care not to tighten cable ties to the point where individual cords cannot rotate freely with them. Use only products manufactured for this purpose, and consider the use of products that can be re-used without the use of tools such as “hook and loop” strapping.
Routing Cords Through Cable Pathways
If the existing cord is the right length, it may be possible to re-use it when re-routing a connection. If this is the case, remove the cord completely and re-run it in through the cable pathways. This is the only way to ensure there are no tangles, kinks or strains. Any unused cords and jumper wires should always be carefully removed from patch panels.
Final Visual Inspection and Panel Closure
Patching must be right first time since mistakes can cause costly disruption and re-work. The time taken to make a final visual check of connections is a good investment. When patch panels are mounted in enclosures, ensure these are securely closed and, where necessary, locked, making sure that cord slack is not snagged or pinched by the doors.
The final step is to update the documentation to the as-built configuration and close the work order associated with the completed change request. Using an AIM system will automate much of this activity and aid the patching process.
If you are looking for a free course, the CommScope Infrastructure Academy offers the Best Practice for Patch Cord Management (WR9301) course. It is a free instructional video that looks at the best practices and recommendations for planning, preparing connections in network infrastructure.