Fluke One Touch - High Voltage

[westin]

Hello, I have a question that stemmed from troubleshooting a system on my network here at the school that I work for. The system was reporting 'a network cable is unplugged.'. The cable was clearly plugged in, so I ran and got my handy Fluke One Touch analyzer, and tested the patch cable. It tested fine. So I thought maybe there was a problem in the cat-6 between the outlet and our patch panel. When I tried to run the test on that, the Fluke device reported:

'Danger: High Voltage detected on RJ45 network, please reset device' [paraphrasing here].

I have used this same Fluke tester multiple times and had never come across this message. I tried all 4 jacks in the classroom, all of them said that. So I went across the hall to that particular teacher's office, and tried the jack in there. It worked fine. No trouble at all.

So I was wondering if anyone here has come across this message. I did not cable the building, nor have I been up in the ceiling, so I don't know the proximity of the cabling to the power lines. The building is only 2 years old, and the cabling was done by contractors as it was built, so I cannot imagine that they would have run the cable along side high voltage lines. Stranger things have happened though. He has another system plugged into one of the outlets that gave me this warning that is functioning on the network. Though I am wondering if the excess voltage may have damaged the card in the other machine, hence the network cable unplugged problem.

I haven't done too much to troubleshoot [ie plugging the machine into another outlet etc], I was mainly concerned with the high voltage message.

Thoughts??

Thanks for any help.

[nihil]

Hi westin,

Jeez man! does that thing have a Zimmer frame or what?.............. have you got the little adapter gizmo for it?

http://www.flukenetworks.com/FNet_ww...ACHEHINT=Guest

Please go to the bottom of the page

I think that the warning is for the Fluke, not your network cable?

I can't remember what model I used to use (could never justify owning one of my own ) but how is it powered? I seem to recall that ours were mains A/C adapter and a rechargeable battery? I would try it on mains if possible, as weak batteries can produce strange results with test meters (never seen it with a Fluke though)

Yeah, cable too close to a mains power supply.............. I have seen that before, and it is common with new buildings that generally settle over the first few years (over here a 10 year snagging guarantee is pretty much standard these days). If the building moves so do the cable runs (ducts?).

If you are at a school I would imagine that parts of it are older? perhaps try your Fluke out there.

I would also get a known working machine and try it on the suspect jack with a different RJ45. If you get the not detected message then it is more than likely EMF interference that is causing it somehow. Some sort of induction current I suppose?

As you are getting this from all the jacks in the room I would rule out the network card socket, although I have seen that before

Luck!

[westin]

Thanks for the quick and informative reply nihil. I do in fact have the 'little adapter gizmo'. I will have to try to run the test again with that in series. I will let you know what happens.

Thanks again!

[SirDice]

One thing that did happen to me and you might want to check it..

We had to move servers to a new rack. All nicely done, we start moving.
Nearly done and I'm about to plug a network cable into a machine....

ZAP.. Big spark.. Scared to living daylights out of me..

Turns out some dumbass hooked up the mains to the ground on an outlet.

[westin]

wow. I might have to check into that as well... that could pose a problem

[keezel]

Lmao - I imagine this isn't supposed to be funny but the way buildings can be wired sometimes is pretty fascinating.