Cat 6 mystery? Can you figure this out

So I just ran two 80 foot cat 6 wires through a ceiling at my work, I terminated the two ends in the server room and put the other two end on the computer side of the run as keystone wall jacks.

I plug in my tester to each end on one of the two wires and absolutely no signal, try the other wire, still no signal, but if I plug a patch cord in the two wall jacks and plug my testers in the other ends of the wires essentially running a signal though both wires in one big loop then it tests fine, what kind of magic is this?

I've run hundreds of wires like that, maybe even into the thousands, so I know what you are doing. Although I don't know how you terminated the wires in the server room, my Spidey Sense is telling me those wall jacks are the culprit. Good luck and please tell us the final outcome.

Ever thought your tester was at fault?

Just my 2 cents.

originally posted by: bananashooter
So I just ran two 80 foot cat 6 wires through a ceiling at my work, I terminated the two ends in the server room and put the other two end on the computer side of the run as keystone wall jacks.

I plug in my tester to each end on one of the two wires and absolutely no signal, try the other wire, still no signal, but if I plug a patch cord in the two wall jacks and plug my testers in the other ends of the wires essentially running a signal though both wires in one big loop then it tests fine, what kind of magic is this?

Trying to picture this in my head.

You run two cat6 lines from the server to a computer room. Let's call them A and B. When you test line A or B, you get no signal. I'm not sure what kind of tester you are using, but mine tests each strand, 1-8. I've seen one or two strands open when running a line, but not all 8. You say you can loop lines A and B with a patch cable in either the server room or the computer room and get a signal. If you're using a patch cable, (and not a normal network cable), and getting a signal, then is seems you have transmit and receive lines crossed, because that's what a patch cable does. The patch cable is re-crossing the lines.

Double check the cat6 lines at the keystones, and make sure the colors are correct. Sounds like you have your oranges and greens crossed.

My best guess, anyway.

If loop you should be making a cross over straight again.

That may be a clue?

Punched to B not A?

You are correct, I have a nice 8 wire tester, double checked key stones and terminals, I have done this hundreds of times, it’s a Klein tester, the only thing I am wondering if When I ran wire through emt had anything to do with it. I am at a loss a reply to: VictorVonDoom

a reply to: bananashooter

Do you have enough slack to undo a punch or take a connector back off?

Do individual lead continuity tests.

(If testing an individual wire, crosstalk/interference issues should more or less be ruled out.)

Can you test the cables individually? - make sure there aren't any broken pins. Are the wall-jacks definitely Cat-6 and not Cat-5 or Cat-5E. 164 feet is about the limit to get high bandwidth.

a reply to: bananashooter

Is it grounded with a 2nd ground, 3rd wire? I'd see if the plates are pos/neg-ground. +. 2nd ground

Definitely cat 6 keystone and terminal a reply to: stormcell

originally posted by: bananashooter
So I just ran two 80 foot cat 6 wires through a ceiling at my work, I terminated the two ends in the server room and put the other two end on the computer side of the run as keystone wall jacks.

I plug in my tester to each end on one of the two wires and absolutely no signal, try the other wire, still no signal, but if I plug a patch cord in the two wall jacks and plug my testers in the other ends of the wires essentially running a signal though both wires in one big loop then it tests fine, what kind of magic is this?

Double check all connections are terminated T568B.

originally posted by: bananashooter
You are correct, I have a nice 8 wire tester, double checked key stones and terminals, I have done this hundreds of times, it’s a Klein tester, the only thing I am wondering if When I ran wire through emt had anything to do with it. I am at a loss a reply to: VictorVonDoom

I have run miles of cable in emt, never an issue. I say reterm your ends. If that doesnt do it, test for a broken wire or two in the run.

You have the cables marked incorrectly. A on one end B on the other.

What Nickn3 said makes a lot of sense, and the behavior you mentioned would fit a scenario of having the cables marked incorrectly.

Anybody that's pulled a lot of cable has made that mistake. Probably more than once.

Worst case, just go "old school" and ring it out with an ohmmeter.

-dex

On the tester I used, which cost about $2K and I don't remember the brand, it would tell you if you crossed the wires and tell you which ones. This was for Cat 5 RJ45's. One of the best investments I ever made.

a reply to: DexterRiley



I tried both wires and even if it was miss wired then it would show lights, it acts as if it’s severed but if I test both together in big loop it tests fine.

a reply to: bananashooter

It sounds like you know exactly what you're doing. And I'm sure you've done all of the obvious stuff; and probably some not so obvious stuff as well. Here's something you might want to think about.

I see you're using a Klein tester. I'm sure it's a nice test instrument. But sometimes these nice test instruments make easy things hard. No matter how much computing power it has, it's still no match for the intuition of an experienced tech.

Maybe use something simpler. The Datashark tester relies on good old lights and wires. Just like Thomas Edison might have used. It's $30.00 at Home Depot. It does the end to end conductor tests, and leaves the analysis to you.

If it works and you solve your problem, then it was probably worth the investment. If it doesn't work, take it back to the store for a full refund. Even if it does help you solve the problem, you can still take it back to the store for a full refund.

If you are at the hair-pulling frustration point, it may be worth the extra trip or two to the big box building supply store.

Just an off the wall idea...

-dex

Main question is did you mark the two runs properly? now normally I'd expect anyone who is able to punch down such kit to have a tester before signing it off (we all make mistakes) but a total 4 pair normally means is bit of a muck up and its been known for someone to pick up some old kit that wasn't terminated in 2000 for some reason and thought it was the right set of pairs for example.