Skinny Patch Cords: What Are They and How Do They Perform?

Written by Don Schultz, trueCABLE Senior Technical Specialist, BICSI TECH, INSTC, INSTF, Fluke Networks Copper/Fiber CCTT Certified

Thin is in! “Skinny” patch cords are becoming all the rage and for good reasons. Server racks and network racks in particular see great benefit as these patch cords make wiring much easier. That all said, there can be some downsides to thin patch cords that you need to know about. Nothing in life comes without some sort of trade-off and so we are going to talk all about the advantages and disadvantages of using thin patch cords!

Note that patch cords can also be fiber optical and coaxial. These components are also referred to as “equipment cords”. For this particular blog we are focusing on copper twisted pair (aka Ethernet) patch cords, terminated at both ends to 8P8C modular plugs (aka RJ45s).

What Are Skinny (Slim) Patch Cords?

Slim patch cords don’t have any specific Category or color. They can be Cat5e, Cat6, or Cat6A and really any color you like. If one were to assign a definition to “slim” patch cords, it would be…

Skinny patch cords defined: Patch cords that are thinner than “typical”, highly flexible, and bend tightly without performance loss, promoting easier installation into high density or other space limited scenarios.

The idea is to make equipment racks easier to patch into, especially with high density installations. High density installations are potentially prone to heating issues, so the thinner the patch cord the more air flow you get. These same svelte patch cords also come in handy for modular furniture, where there is very little space to route cable.

Ideal Use Cases for Thin Patch Cords

• Data centers, network closets, high-density switch panels
• Short patch runs between rack equipment
• Environments where airflow and organization are priorities

How are Skinny Patch Cords Constructed?

There is nothing in the TIA standard that demarcates what is or what is not a thin patch cable. In fact, there is nothing in the standard that even indicates how thin you can go. No, instead, the rules of the road around construction are rather loose and defined by the ANSI/TIA-568.2-E - Balanced Twisted-Pair Telecommunications Cabling and Components Standard. The specific section is 5.5 “Cord Cable Mechanical Performance”.

TIA Defined Patch Cord Construction Requirements:

• CCA (copper clad aluminum) is not permitted
• Conductors may be stranded or solid copper
• There must be four balanced twisted pairs (eight total conductors)
• Conductor gauge may range from 22 to 28 AWG
• Conductors must be insulated with thermoplastic
• Conductors must be enclosed inside a thermoplastic outer jacket
• Shielded patch cords must survive 500 flexes under specified conditions and still perform as required

Note that there are no minimum or maximum overall jacket diameters specified for cord cables. A cable jacket type (fire rating) is not specified as that would depend on the particular installation requirements. Technically, cord cables need not even be marked with a performance Category! Pretty loose guidelines, eh?

Reality would dictate you won’t achieve what anyone would consider a thin patch cord using 22 AWG conductors and shielding. You would end up with a thick patch cord, despite any herculean efforts.

So, the implications are that “skinny” patch cords are in the eye of the beholder. Generally speaking, thin patch cords are constructed from 28 AWG stranded pure copper conductors, and are generally less than 4.00mm thick (jacket OD). Shielding is often not employed in skinny patch cords, given that shielding will work to defeat the whole purpose of skinny patch cords which is a tight permitted bend radius and…well…thin.

Beware ultra thin patch cords. You will see 30 and even 32 AWG conductor patch cords for sale. These super skinny patch cords are not standards compliant and thus are considered counterfeit.

Key Benefits of Slim Patch Cable

• Improved airflow in racks and cabinets
• Easier cable management and organization
• Higher port density (more cables in less space)
• Lighter and more flexible for tight corners

Is There a “Standard” Patch Cord?

Not really, no. There is a “generally accepted” patch cord making use of 24 AWG stranded copper conductors, however. This general acceptance is borne more out the maximum channel length of 328 feet while using a 295 foot maximum length permanent link (channels are the permanent link plus a patch cord at both ends). Where did this come from? The TIA standard is geared towards commercial buildings and standard floor space sizes, where the typical network wiring closet (called a TR or telecommunications room) is limited to serving 10,000sqft. Given those parameters, the maximum length of a “rack to jack” permanently installed copper twisted pair Category cable is 295 feet. The maximum permanent link length applies to Cat5e through Cat6A. Solid copper conductor Category cable is used to construct that link, and 22 to 24 AWG may be used.

The 328 foot part comes in when you use stranded copper patch cords to patch into the permanent link to create your communications channel. Per the TIA standard, 2 x 16.5 foot 24 AWG stranded copper patch cords (33 feet total) is permitted to achieve the 328 foot channel limit. Of course this will take on many variations depending on permanent link length and copper gauge of the patch cords. You can see a de-rating chart in Calculating Ethernet Cable Overall Channel Length for Success.

Needless to say, the thinner the stranded copper patch cords are the shorter things get. This brings us to the next topic…

Limitations of Skinny Patch Cords

As stranded copper gets thinner, your lengths permitted get shorter. This is not a “1 for 1” phenomenon, however. It is logarithmic! Here are some of the highlights of performance limitations you will encounter:

• You will not reach the maximum permitted 328 foot channel length using 28 AWG patch cord. Given a maximum length solid copper permanent link of 295 feet, your maximum channel length is 315 feet which would be 2 x 10ft 28 AWG patch cords (total 20 feet).
• The absolute maximum amount of 28 AWG patch cord permitted is 49 feet, even if the 28 AWG patch cord is the entire channel with no permanent link at all.
• Power over Ethernet cable bundle size is reduced. Although any one 28 AWG patch cord will work with 100W (DC) PoE, there are limitations around how many you can bundle together due to increased heat. Please see Power over

This table reveals how copper gauge of the patch cord, combined with permanent link length (or no permanent link at all) affects how far you can go:

TIA-568.0-E De-Rating Chart for Patch Cords. The highlighted column is 28 AWG.

Notes on using this table:

• D= De-rating factor applied using an equation, so…
  • D=1.0 means solid copper is used for the patch cord, no de-rating
  • D=1.2 means 24 AWG stranded copper patch cord
  • D=1.5 means 26 AWG stranded copper patch cord
  • D=1.95 means 28 AWG stranded copper patch cord
• Link= permanent link length

When to Skip Thin Patch Cords

• You have no intention of using permanent links and wish to run patch cords only, but need to go past 49 feet
• Large bundle sizes of skinny patch cords carrying 30W or higher PoE wattage
• Bundles of patch cords that must be installed into conduit and carry PoE of any wattage

What to Look for When Purchasing Slim Patch Cables

The primary concern when making the purchasing decision around patch cords is not accidentally buying a counterfeit one!

The vast majority of patch cords out on the mass market won’t pass Certification testing. The issue is rather severe.

How severe? Here is an industry quote, from a highly reputable source. trueCABLE has cross confirmed this information with our own testing.

“To get an idea of equipment cord quality, the Communications Cable and Connectivity Association (CCCA) completed large-scale, electrical performance testing of Category 6 copper patch cords, which tested nearly 500 samples that included 379 cords from offshore, lesser-known manufacturers and 120 cords from well-known North American manufacturers. Of the 379 offshore patch cords, 322 of them failed electrical performance parameters specified in TIA 568-C.2 standards with 78% failing by a margin of 3dB or more and 45% failing by a margin of 6dB or more. These cords would have likely led to significant network problems once included in the channel. All the patch cords from recognized North American manufacturers showed 0% failure rate.”- Fluke Networks

What to look for in a skinny patch cord:

• Select a reputable manufacturer from the start
• Do not select a patch cord with conductors thinner than 28 AWG
• Conductors should be of pure stranded copper
• Cord should be Component Rated and Certified to a certain Category at the factory -- not simply “verified” or “tested” as you don’t know what kind of test was actually performed
• UL or cETLus Listing for cable jacket fire safety factors

Conclusion

So there you have it! The skinny on slim patch cords. A major boon to IT personnel and even structured cabling system installers, slim patch cords provide a level of flexibility (literally) to create higher density racks and perform installations that were difficult to achieve in the past. Keep in mind that you want a Component Rated and Category Certified patch cord, and in addition keep in mind the limitations that can surround thin patch cords and your installation will be easier to work with.

HAPPY NETWORKING!

trueCABLE presents the information on our website, including the “Cable Academy” blog and live chat support, as a service to our customers and other visitors to our website subject to our website terms and conditions. While the information on this website is about data networking and electrical issues, it is not professional advice and any reliance on such material is at your own risk.