Video and 100v P.A. in Cat5e

I expect you should discuss the matter with your cabler as he would certainly be able to resolve the issues . the video and audio need to be separated coincidently so following the rules pertaining would be advisable , I assume you intend using a decent analogue cctv camera so conventional duo coax and power combo would server perfectly .

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**Running 100 Volt audio over Cat5e is a recipe for disaster. Although it MIGHT work, it also could cause damage to video equipment, if problems occur. Much better to run a dedicated 100 Volt line. Ordinarly speaker cable is usually adequate.

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Trevor Wilson www.rageaudio.com.au

Have had no trouble running 70-100v PA lines and RS485 data in the same cable, longest we have tried is about 100m, and in come cases this has been run right next to video cable, (not balanced line). Never caused a problem.

While its definitely not the proper way to do it, I have run AV video unbalanced video through cat 5 over a few metres without problems, but go over about 10-15m and some interference starts. (usually horizontal white dotted interference lines in 1-3 places across the picture).

Best way is probably to just do a dummy run on the bench (or just do a temporary run between the 2 locations using a length of the cable in question. I have a feeling it will work fine, but you don't want to go to the hassle of running cables and conduits only to find that it doesn't work as you want it to.

Whether you are supposed to do things like this or not is another matter, and whether CAT5 is rated to handle 100v lines is another matter again. IIRC if you use a separate cable for the 100v line, it is supposed to be double insulated.

Thanks for the quick replies. To play it safe, I will use CAT5e with baluns for only the camera video signal.

The 100v P.A. signal will be sent through a separate speaker cable. If this cable should be double insulated, would 2 pair telephone cable be suitable, the 2 pairs could be connected in parallel.

Before making the installation permanent, I will temporarily put both cables beside each other to see if there is any interference visible.

Thanks, Russell.

Incidentley cat is rated to 50 volts only being elv

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As the telephone line (in Australia) goes to over 100v ac to ring the bell the cable should be adequate for a 100v line use. (Note - it would not be suitable for

110v mains applications)

As for it being thick enough, it depends on how many speakers will be run off it and what wattage. I think up to 50w or so per pair would be fine but if you are running a lot more than this, and are suffering volume drop, you will need thicker conductors.

If you aren't using the telephone cable for anything else other than the 100v line, I would simply parallel the pairs, so if you are using 2 pair (4 core) - then use 2 of its wires in parallel for one of the connections and the other 2 wires in parallel for the other side of the 100v line. This should be good for close to an amp (100w load) over the 5 metre length you are quoting.

What I have seen used commercially for this job has a oval brown outer sheath, red and black inner wires and from memory would be about 0.5mm sq.

Note that if this is for an emergency announcement system - such as fire for example, do not muck around, use exactly the same sort of cable size as what is on the rest of the system. It also may have to be fire resistant cable also.

Thanks for the extra info. The system is not critical. As well as the 5m between buildings, there will also be several meters of cable required inside each building (yet to be worked out). I may end up using thicker double insulated cable. Many details are yet to be worked out, but the info. provided will be helpful.

Thanks, Russell.

Middies sell a suitable combo cable , power and coax with sheath which is vermin resistant so woddles and philthy might leave you alone , ideal for your use and good out to several hundred metres

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