Two reels can both say Cat6 and behave nothing alike. The category sets a floor, not a level, and the differences that matter are the ones that do not appear in the product title. Here is what to check, in the order that affects the outcome.
Figure 1: ISO 9001 certified cable manufacturing plant with automated extrusion and testing lines.Quick answer
Check | What good looks like |
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Conductor | Solid bare copper, stated explicitly |
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Gauge | 23 AWG typical for Cat6 |
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Jacket rating | Matched to the space it will be installed in |
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Shield, if present | Designed to be bonded at the terminations |
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Test data | Component measurements, available on request |
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Legend | Category, gauge, temperature rating and listing mark printed on the jacket |
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1. The conductor
This is the first check because it is the one most often left off a listing.
The category’s performance is written against solid copper. A copper-clad aluminum conductor has a different resistance and behaves differently at the frequencies the cable is rated for. It is not a cheaper version of the same product; it is a different product that carries the same category label on some listings.
Ask directly. If a supplier cannot state the conductor material in writing, that is an answer in itself.
2. The gauge and the construction
23 AWG is the typical Cat6 conductor, against 24 AWG for Cat5e, and the half-step is part of how the cable reaches 250 MHz. A listing that quotes nothing about gauge, or quotes a much thinner one, deserves a second look.
Solid against stranded is the next question. Permanent links want solid conductor; patch leads want stranded. A reel sold for permanent installation that turns out to be stranded has given away attenuation margin the channel design assumed.
3. The jacket rating
The jacket rating decides where the cable may legally be installed. It is driven by fire performance, and it varies by jurisdiction and by the space — a plenum ceiling, a riser, or a general-purpose area each have their own requirement.
This is not a quality distinction in the electrical sense. A cable with the wrong rating for the space is not a worse cable; it is a cable that cannot be used there. Getting it wrong is a code issue and often an inspection failure, and it is discovered after the cable is installed.
4. The shield, and whether it can be used
Unshielded cable is the default in offices, and for most installations it is the correct answer. Shielded constructions exist for environments with real electromagnetic noise or for high-density bundles where alien crosstalk is the limiting factor.
Two questions decide whether shielding helps:
Is there an actual noise problem? A shield addresses interference from outside and coupling between cables. If neither is present, the shield is cost without benefit.
Can the shield be bonded? A screen only works when it is connected to ground at the terminations, with panels and outlets designed for it. An unbonded shield can make things worse by acting as an antenna along the length of the run. Shielded installations also need the grounding and bonding system to be in place, and adding a shielded island to a building that is unshielded everywhere else raises a question about where its ground reference lives.
The naming conventions for shielded constructions are covered in our shielded cable guide, because the abbreviations are easy to confuse and the order of the letters describes the order of the layers.
5. The test data
Ask for component test data on the actual product, not a compliance statement in a brochure. A test report shows the measured values against the limits, which is the only way to tell a cable sitting comfortably inside its specification from one scraping past it.
For a project with marginal runs, this is the difference between a channel that certifies with margin and one that certifies on a cool day and fails in summer.
About buying by brand name
Most searches in this space include a brand, because brand is the easiest thing to search for. It is not a specification, and it does not replace any of the five checks above.
The useful distinction is between a supplier who publishes data and one who does not. A named brand with a published datasheet and test data gives you something to verify. A brand name alone, on a listing with no category detail, no gauge and no conductor statement, gives you nothing to check — regardless of how familiar the name looks.
So the practical approach is the same as for an unbranded reel: ask for the category, the conductor, the gauge, the jacket rating and the test data. If those five answers come back, the name on the box stops mattering. If they do not, the name will not save you.
A pre-purchase checklist
- Is the category stated, and is it the one the design requires?
- Is the conductor stated as solid bare copper?
- Is the gauge stated, and does it match the category?
- Is the jacket rating stated, and does it match the space?
- If shielded, is the construction named, and will the terminations be bonded?
- Is test data available on request?
- Is the legend printed on the jacket, and legible?
- Does the ordered quantity match the channel lengths, including cordage?
- Is there a certification requirement in the specification, and who is doing it?
Nine questions. Any listing that cannot answer the first four is a listing with an unknown product behind it.
Field scenarios
A contractor comparing three reels at three prices. Compare conductor, gauge and test data rather than price alone. Same category, different copper, different result on the long runs.
A buyer who found a very cheap reel online. Ask for the conductor statement. If the answer is that the conductor is clad, the price is now explained rather than suspicious.
An office buying cable for a ceiling void. Confirm the jacket rating before ordering. The electrical performance is unaffected by the rating; the legality of the installation is entirely determined by it.
FAQ
What makes a Cat6 cable good?
Solid bare copper conductor, 23 AWG, a jacket rating matched to the space, no unnecessary shield, and published test data. The category alone does not distinguish between a good and a poor example.
Is pure copper better than copper-clad?
They are different conductors. The category specification assumes solid copper, and a clad conductor does not behave identically at the rated frequencies.
Do I need shielded Cat6?
Only where there is a real noise problem or an alien-crosstalk constraint, and only if the shield will be bonded at the terminations.
Is a more expensive cable always better?
No. Price tracks copper content, jacket rating, shielding and brand, and not all of those are relevant to a given installation.
How do I know the cable is what the listing says?
Read the legend printed on the jacket. It carries the category, gauge and temperature rating, and it is the only identification a buyer can verify directly.
Should I buy cable with a certification program attached?
If the project requires channel certification, yes — and confirm who is performing the test and to which standard before the cable is ordered.
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