Cat5e, Cat6,Or Cat6a?

Three cable grades, one question, and a great many people being sold the expensive one. Cat6 is the sensible default for a house, a church or a small office being wired today — and where Cat5e is already in the walls, it is very often fine exactly as it sits. What makes a network slow is almost never the category printed on the jacket. We install cable for a living and do not sell it by the box, so this page has no reason to talk you upward.

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Cat6 by defaultFor anything new

Cat5e is not deadA gigabit to 100 m

55 m versus 100 mThe 10 Gb argument

Termination decides itMore than category

The short answer

You are probably being soldMore cable than you need.

The whole comparison, before any of the detail. If you read nothing else on this page, read these four, because they are the version we would give you standing in your garage looking at the panel.

If the walls are open, run Cat6

Cat6 carries a gigabit to the full 100 meter channel, exactly as Cat5e does, and it gives a run some headroom past that. It is the sensible default for a house, a church or an office being wired today, and the reason is not speed — it is that the walls are only open once.

If Cat5e is already in the walls, leave it there

Cat5e is specified for gigabit Ethernet across the full 100 meters, and gigabit is more than the internet service arriving at nearly any building around here. Tearing working cable out of finished walls to chase a number that nothing in the building can use is a large amount of money spent on nothing.

Cat6a where there is an actual 10 gigabit plan

Cat6a is the only one of the three specified to carry 10 gigabit Ethernet across the full 100 meters. That is worth paying for on a short backbone run, in a rack where the uplinks already move more than a gigabit, or in a building going up now where somebody has written down what the 10 gigabit is for.

The cable is almost never the bottleneck

When a network feels slow, the cause is usually the gateway, an overloaded uplink between switches, an access point mounted in the wrong place, or the handoff from the internet provider. A different category of cable does not fix any of those, and it is the most expensive way to not fix them.

What actually decides it

Six things worth knowingBefore anybody quotes you.

The standards are precise and the marketing around them is not. This is the precise version, including the parts that argue against spending more.

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What the categories actually are

Cat5e, Cat6 and Cat6a are performance grades within one cabling standard. They are not brands and they are not different kinds of wire. All three are four twisted pairs, eight conductors, terminated on the same eight-position modular connector, which is exactly why they look identical behind a wall plate. What changes is the twist, the separation between pairs, and how well the cable rejects interference from its own pairs and from the cables lying against it — and therefore the frequency the standard tests it to: 100 MHz for Cat5e, 250 MHz for Cat6, 500 MHz for Cat6a. A higher grade does not make a network faster on its own. It raises the ceiling on what a run is permitted to carry.

The 55 meters everybody argues about

This is the number that sells cable. Cat6 supports 10GBASE-T only to roughly 55 meters, and less than that in a tightly bundled run, because neighboring cables interfere with each other — alien crosstalk, which is the specific problem Cat6a was designed to solve. Cat6a supports 10GBASE-T across the full 100 meters. Both statements are true, and in most buildings both are beside the point. The question is not whether the cable could carry 10 gigabit, it is whether anything in the building will ever send 10 gigabit down it. Worth knowing alongside it: every category shares the same 100 meter horizontal channel limit, 90 meters of solid cable in the building plus up to 10 meters of patch cords at the ends. That limit belongs to the Ethernet standard rather than to any cable grade, and it is the constraint that actually decides where the rack goes.

Why it is slow, and why it is not the cable

A network complaint is a chain of links, and the speed is set by the slowest one. It is the gateway the internet company left, doing more work than it was built for. It is a single gigabit uplink between two switches carrying a whole floor. It is an access point mounted where an outlet happened to be, three rooms and a brick chimney away from the people using it. It is the handoff from the provider, the one part of the chain nobody inside the building controls. It is the device on the far end, which in most homes and offices has a gigabit port and nothing more. The run in the wall is rarely the link that is limiting anything, and replacing it changes a ceiling that was never being hit.

PoE, and heat in the middle of a bundle

For most buildings now this matters more than category does. Cameras, wireless access points, door readers, phones and displays take power over the same cable that carries their data — 802.3af up to 15.4 watts at the switch port, 802.3at up to 30 watts, 802.3bt up to 90. Power in a conductor becomes heat, and a cable buried in the middle of a large bundle inside a closed pathway has nowhere to put it. Heat raises insertion loss, and insertion loss is what limits distance. A building full of powered devices cares more about bundle size, pathway and conductor gauge than about whether the jacket reads 6 or 6a. This is one place the heavier cable earns something real, because a larger conductor carries the same current with less heat, and the higher categories are commonly built with heavier conductors.

When Cat6a is genuinely the right call

There are real cases and they are specific. A short backbone or riser run between the main rack and a secondary closet, where an entire floor is aggregated onto one link. A dense rack where switch uplinks and storage already move more than a gigabit. A building under construction, where the walls are open, the cable will be there for thirty years, and the 10 gigabit is a plan rather than a hope. It is also worth knowing that TIA guidance for cabling to wireless access points recommends Category 6A, even though most small buildings do fine without it. What gets left out of the comparison is what Cat6a costs you physically — it is thicker and stiffer, it wants a larger bend radius, it is harder to terminate cleanly, and it eats room in a conduit, a J-hook, a stud bore and a patch panel. On a retrofit through finished walls, none of that is a small thing.

Termination, pathway and testing

This is the part that decides how a run performs, and it is the part nobody shops for. A badly terminated Cat6a run performs worse than a properly installed Cat5e one, every time. An inch of pair untwisted at the jack, a cable pulled past the published 25 pound tension limit, a staple driven tight, a kink around a joist, twenty feet of run laid against line voltage — each of those takes performance out of cable that was perfect on the reel. The way to know is to test the finished link against the standard for wire map, length, insertion loss, crosstalk and return loss, and to keep the result. Cable is a commodity. Installation is not, and the gap between a good install and a careless one is wider than the gap between two categories.

Where the run goes

The category question is reallyA question about distance.

Every argument about Cat6 against Cat6a is an argument about how far a run goes and what sits on the end of it. Which means it is answered by the drawing, not by the box the cable came in.

What each carries

All three grades carry a gigabit across the full 100 meter channel, which is the row nobody puts on a box. The only line separating them is 10 gigabit — not rated on Cat5e, roughly 55 meters on Cat6, and the full 100 meters on Cat6a.

Where copper stops

A section through a metal building, with copper running from the rack out to the 100 meter limit and fiber carrying the rest of the way to a remote closet. Past that limit no category helps, because the constraint belongs to the channel rather than to the cable grade.

Termination decides it

Twenty-four ports numbered to match the wall jack at the far end of each run, patched down to the switch below. A properly installed Cat5e link outperforms a carelessly terminated Cat6a one, which is why this end of the run settles more than the letter printed on the jacket.

Shielded versus unshielded

Shielded cable is sold as an upgrade.It is only one if it is bonded.

Foil around each pair, a braid around the bundle, or both. It gets quoted as the better version of the same cable. It is not. It is a different tool for a different building.

What shielding is actually for

Shielded cable rejects interference coming from outside the cable, and there are buildings where that is the right call and nothing else substitutes for it — a shop floor full of variable frequency drives, a run that has no choice but to share a pathway with line voltage, an imaging suite. If that describes the building, use it. It is not a general upgrade, it is a specific answer to a specific electrical environment.

A shield does nothing until it is bonded

The shield has to be bonded and grounded properly and continuously, from one end of the link to the other — shielded jacks, shielded patch panels, shielded patch cords and a real path back to the building bonding point. All of it, not most of it. A shield left floating at one end, or tied to two grounds sitting at different potentials, can carry current and behave as an antenna instead of a screen. A poorly bonded shield is worse than no shield at all. Unless the building genuinely calls for it, unshielded cable installed well is the better answer for a home, a church or a small office, and it is easier to terminate correctly — which, per the section above, is the thing that decides performance anyway.

How the cable actually gets installed

Common questions

Asked by people who haveAlready been quoted the upgrade.

Usually after somebody told them the wire in the house is obsolete. It is generally not.

Is the Cat5e already in my walls good enough?

Usually, yes. Cat5e is specified for gigabit Ethernet across the full 100 meter channel, and a gigabit is more than the internet service arriving at nearly any house, church or small office in West Georgia. It will also commonly carry 2.5 gigabit over a full run and 5 gigabit over a shorter, well installed one, because those standards were written specifically so that existing Cat5e and Cat6 would not have to come out of the walls. If the network feels slow, pulling out working cable is close to the last thing to try rather than the first. Test the run, look at the gateway, the uplinks and where the access points are mounted, and replace cable when a test says the cable is the problem.

Do I need Cat6a for a home?

Almost certainly not for the runs out to the wall plates. Cat6a exists so that 10 gigabit Ethernet works across the full 100 meters, and in a house the devices on the end of a horizontal run are gigabit devices, connected to an internet service that is slower than that. Where it can earn its place in a home is a short backbone run between the equipment rack and a secondary closet, or a run to one location where something is known to be coming later. Cat6 is the sensible default for everything else. Anyone recommending Cat6a for a whole house should be asked, plainly, what is going to use it.

Will better cable make my internet faster?

No, in almost every case, and the reason is worth understanding. Speed is set by the slowest link in the chain, and the cable in the wall is rarely that link. The chain runs from the internet provider, through the equipment they installed, through your router or gateway, through a switch, down the cable, into the device — and most of those devices have a gigabit port. A Cat5e run in good condition already carries a gigabit, which is more than the connection coming into most buildings. Upgrading it raises a ceiling nothing was touching. If a wired connection is genuinely slow, the useful step is finding out where the loss actually happens, which means testing the run and looking hard at everything between it and the outside world.

Can Cat6 and Cat5e be mixed in one building?

Yes, and most buildings that have been added to over the years already are. Every category terminates on the same eight-position modular connector and they work together without anything special. The part to understand is that a single run performs to the weakest component in it — a Cat6 cable landing on a Cat5e jack, or patched with a Cat5e cord, is a Cat5e channel end to end. So mixing categories across a building is fine, and mixing them within one link is not. When we add drops to an existing building, the new runs go in at the current standard and the working older runs stay where they are.

How do I tell what cable is already installed?

Read the jacket. Cable is printed along its length with the manufacturer, the category and usually a footage marker, and the easiest place to see it is where the cable comes out at the equipment rack, or behind a wall plate. A jack is one or two screws and it comes forward on its cable far enough to read the print. The jacks and patch panels are often marked as well. What the printing does not tell you is whether the run was installed and terminated properly, or how long it is, and both of those matter at least as much as the category does. A certification test answers both, and it is the honest way to settle an argument about cable.

Who wrote this

We pull the cable.We do not sell it.

CDM Systems, LLC is a low-voltage contractor working out of Bremen, GA 30110 — structured cabling, networks and wireless for homes, churches and small businesses across West Georgia. Nobody here makes money on which category you pick, which is why this page is willing to end with the answer being no.

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