DMX on CAT5....to shield or not to shield?

all the dmx lines in our building are regular cat5 cable. no problems, 288 dimmers for 14 conference rooms

Unless something major has changed since I moved to Germany 4 years ago….When using CAT5 for DMX the cable must be in metal conduit from point to point.

I too have seen installations where it was not and times where there was conduit at the back-box but it dispersed once it reached above the drop ceiling. In some cases there have been no issues with this. In some cases issue did not arise for over a year or two. In some cases there were DMX problem right at the time of turn-on.

Sincerely,

Mike  

Mike,

          I've seen a few jobs where the DMX installed wrong and failed years later. I always hate coming in after the fact to tell the end user that the poor install  is the cause of their headaches..

This remains true. CAT5 is to be in pipe when used for any form of RS485 or RS422, when unshielded. Im trying to dig up the article I have on it., but can't seem to find it at the moment. If I find it, I'll try to post it.

Your results may vary, but its a really hard thing to track down when a problem occurs without replacing the wire plant. Its interesting to see a scope shot of a CAT5 line with DMX that is drapped over a Fluresent light fixture.

Shielded CAT5 is an interesting alternative, but really not very popular in the U.S. It also requires different RJ45 female jacks. Works great, but more expensive. (However I believe its still significantly cheaper than 9729 or running Pipe, however still just as physically fragile).

One important thing to remember is that on installation the wiring plant will be in it's best condition and will begin to degrade the moment you drive it off the lot <grin>.  Unshielded Cat 5 not running in pipe is, as Skurla says, a fragile thing.