How far from flourescent lights should UTP cat5 be?

[DDDavey]

We're running panduit down one side of a ~6' wide hallway. In order to get cable to the other side of the hallwe have to run it across the ceiling. Is it ok to run it right under the lights? or go to teh end of the lighg then across? or should we go across teh ceiling halfway between 2 lights so as it's far away as possible? thanks!

BTW, this will be ~15-20 user network. Max dist' switch to comp will be ~200'

 

[ScottMac]

AS far away as possible would be best.

If you can do that, then across the middle of the tube would be second best.

Third choice would be across the end that doesn't have the starter/balun.

Avoid the end that has the starter/balun.

Good Luck

Scott

 

[cipher00]

As far away as possible. Several feet should do the trick, but more is better.

Good luck.

 

[jehh]

If at all possible, I'd keep it away from the whole light thing. Can you not go around it? (cable isn't THAT expensive...

Jason

 

[ScottMac]

As mentioned above, total avaoidance is the best path.

FIfty/sixty cycle is not that big of a deal, the construction of the cable (assuming proper pairing, etc) and the modern transceivers in the switches/hubs/ routers can pretty much ignore common EMI.

The concern with flourescents (regular light bulbs are totally benign) is when they get old/are dying/baluns are dying, they generate a great deal of impulse noise, which the cable/transceiver combination has a much harder time dealing with.

Avoid 'em if you can, if you can't, minimize the potential problems by keeping it away from the starter/balun end of the fixture.

FWIW

Scott

 

[randal]

The effects of flourescent lighting disappears if the lights are turned off, correct?

We have 2 such lights in our server room, but they are off -- hoping they are not still impeding performance.

randal

 

[ScottMac]

ooooooooo...candles in the server room, another sign of a kinder, gentler data networking evolution.....Pretty soon they'll be pumping in Montovoni; maybe keep some brie on top of the 7514 with a bottle of white in the chiller. This could be good. Sell your stock in Domino's Pizza and Pizza Hut.

Sorry folks, the drugs made me do it.....

Scott

 

[edmicman]

so lighting can disrupt cabling, eh?  does it just slow it down, or can it cause anomalies galore in the network?  we've been having some problems lately with our web server performance, with packets being dropped off and on, but its not happening steadily to be able to figure out what the heck is causing it.  the web server and cable modem cables aren't near lights, but i think other cables that go out to our LAN might be running nearby, if not right next to some fluorescent lighting.  is there a way to test this?  thanks!

 

[ScottMac]

SOME electrical fields/noise can distort the data, causing more re-transmissions. If you put an analyser, like a Sniffer (Ethereal, Snort, etc) on the cable, it should be fairly easy to determine what's causing the slowdown.

You got a statistical ~80% chance it's your cabling somewhere.

FWIW

Scott