Do You Use Flat Ethernet Cable?

Flat Cat: It's so nice, but it just doesn't seem right...

Assuming you don't mind paying the premium, is there a good reason not to use it?


Nope. I would not recommend Flat Cables. Without twists your susceptible to EMI interference, and packet collisions. No self respecting cable guy should ever use these as a long term solution.

The individual pairs are twisted together, just not the groups of pairs.

I agree with all things U2 said and add that you can't dress a flat cable as well as a standard cable :)

No self respecting cable guy should ever use these as a long term solution.

What about as a traveling cable in an elevator?

It's very hard, but not impossible, for flat cables to pass category ratings. In my previous integrator life, there was a special Cat 5e flat cable that was used in nurse call systems. Don't ask me why it needed to be flat...but that's what the manufacturer specified.

I use some flat cables around my house because it's easier to hide under carpet, but it is a pain to work with sometimes, since taking corners is a hassle.

I do use some flat cable sometimes when I need to close a door on it for temporary testing. But closing a steel door on any cable flat or not leads to it wearing out.

In commercial systems I don't really see much point to it unless you have to hide it somewhere.

It's very hard, but not impossible, for flat cables to pass category ratings.

Why would it be 'hard'?

Most likely due to crosstalk issues between adjacent pairs. In a normal round cable, the 4 pairs are twisted together inside the jacket (you've seen this if you've ever stripped a cable jacket back more than a few inches). My understanding is that this overall twist helps reduce crosstalk issues from parallel pairs.

In a flat cable, the pairs run perfectly parallel to each other for the entire run of the cable. This can potentially increase the chances of crosstalk between pairs.

What he said. Category cables are intended to work as an assembly, and the individual twists and overall twists are designed to function together. I'm not saying you can't find a flat category cable. I'm saying it's not that common among reputable manufacturers, and you can't simply take the same pairs you'd stick in a round cable and expect they'll pass a test. They might/might not pass.

But none of us are UTP engineers, unless there's something I don't know, so debating the hypothetical is pointless. I've been told the above by more than one cable manufacturer.

But none of us are UTP engineers.

Totally agree, that is why we have standards to rely on.

So even if it is 'harder' for a flat cable to achieve a rating, we should look only at the manufacturers rating and our own field certification as to its expected performance.

Btw, there are quite a few cat 7 flat cables out there as well. I would really like to see if they are full of s**t, but I don't have a cat 7 certifier on hand...

In a flat cable, the pairs run perfectly parallel to each other for the entire run of the cable.

Actually, and IMHO, in Cat6 cables and others with a spline (it's that plastic cross shaped thing in the center of the cable that enforces an equidistant separation), the conductors also run (geodesically in this case) parallel. At any given point in the cable pair x will be the same distance from pair y, and at the same angle, even as they twist together. Euclid be damned.

The reason for the spline is to seperate the pairs physically as much as possible to reduce crosstalk.

The reason for the spiral (twist) is to reduce alien crosstalk, i.e. the crosstalk between pairs in different cables in the same conduit. The spiral insures that the brown from one cable will not run for any length next to the blue of another, for instance.

Flat cables lying flat on top of each other would be more susceptible to alien crosstalk one would suppose.

Also, I am unable to find any EIA-TIA specification relating to how much or even if the individual pairs should be twisted. I am unable to find anything about flat cables at BiSCI, but I may have missed it.

To whom I was unhelpful: If I have said something inaccurate, please, by all means correct me. As a courtesy to others who might be misled.

Or at least "Disagree" also.

I voted an "informative."

I recall in the mid eighties when a salty old telecom guy sat me down and explained to me how twisted pair works (this was for serial communications cables we were building at the time). He was a dinosaur who never got into digital networking, and probably retired not long after that lesson. But it stuck with me as the basic fundamentals behind category-this and category-that. So I'll never scoff at anybody's explaination of the reasons behind the technology/standards (as long as it's accurate).

Carry on.

Ethan,

flat cables are always specified in nurse call systems so if at any time it ends up on a floor, a wheel chair is easily able to roll over it.

A few years ago we wanted to install Axis IP cameras in elevators. Due to not performing an elevator upgrade and installingnew traveling cable we could not use CAt5 or Cat6. Code would not let us install a cat 5 or Cat 6 cable in the shaft. So we went with a wireless system.

A couple of years later we were doing an elevator upgrade in another building. All equipment was gonig to be replaced. To include the traveling cable. Again we were told tyhat per code we could not use Cat 5 or Cat 6 in the travel cable. So we went with a fiber solution.

In-store Wal-mart flat Ethernet cable. Says CAT6, no a, no e. This Wal-mart 'spec sheet' goes beyond the usual non-informative consumer oriented mush, edging into pure incoherence with its three apparently conflicting data points:

  • CAT6 network cable with 1Gbps transfer rate
  • Compatible with 10Gbps equipment
  • Up to 10Gbps transfer rate

bucks 7 ft 4 bucks = 28AWG

Wouldn't have normally got it but they were sold out of CAT7...