Cat 3, ptz, my options

[shockwave199 0]

Ok, so I'm finally gonna tackle this thing- try and bare with me cause I need help with this one.

 

Power supply for this camera- 12v 4a.

 

I already have bcn in place from another camera I will be pulling out.

 

I have 50' of cat 3 doing nothing. I thought I would use this for the comm to the ptz and the remaining two pairs twisted together and put on a male barrel connector for the camera side. The barrel connector is being cut off the power supply that came with the camera, since it's the only barrel that fits the female barrel on the camera for some reason. So the power supply will have no barrel. Here's my questions-

 

- Will the remaining two pairs be enough for the power?

 

- Can I leave off the barrel connector on the power supply side and just wire it right up the the two pairs?

 

- If I wire a barrel connector back onto power supply, can the gauge of the lead be one gauge thinner than the power supply wire? My barrel lead is a little thinner than the power supply wire.

 

I'd really like to wire in the power supply right to the cat 3 twisted pair, as I will be cutting the cat 3 back to around 30' and it'll be easier to wire it in up in a hot attic if I didn't have to dick around wiring in a barrel connector.

 

Thanks a bunch for you help!

[Soundy 1]

I have 50' of cat 3 doing nothing. I thought I would use this for the comm to the ptz and the remaining two pairs twisted together and put on a male barrel connector for the camera side.

You only need one pair for the comms; if you're using the Cat3 for power, use all three other pairs.

 

Will the remaining two pairs be enough for the power?

Depends - what's the length of the run, and what are the current requirements of the camera? PTZs tend to be rather power-hungry; however, three pairs of 24ga. is approximately equivalent to 18ga.

 

Can I leave off the barrel connector on the power supply side and just wire it right up the the two pairs?

Yup, just make sure you get the polarity right.

 

If I wire a barrel connector back onto power supply, can the gauge of the lead be one gauge thinner than the power supply wire? My barrel lead is a little thinner than the power supply wire.

Sure.

 

I'd really like to wire in the power supply right to the cat 3 twisted pair, as I will be cutting the cat 3 back to around 30' and it'll be easier to wire it in up in a hot attic if I didn't have to dick around wiring in a barrel connector.

Go for it.

[shockwave199 0]

You only need one pair for the comms; if you're using the Cat3 for power, use all three other pairs

I have cat 3 telephone installation cable, to be exact. It has three pairs. One pair I'd use for comm, the other two pairs I would use for power. Run to be approx 30'.

[tomcctv 187]

hi. cat3 if it is this type.

 

 

 

 

 

this type of cable is much thinner than cat5 and with 12v 4 amp over that distance amps may be a problem.

 

you could use your coax for the power (bigger core) and just put a balun on 1 pair of your cat3 and another pair for your data.

[Soundy 1]

^That's not Cat3, either - the cable "categories" refer to different specs of twisted pair. That stuff in the picture is just flat cabling. Not that it won't work, just wanting to clarify terms.

 

Plus, the rating of the power supply doesn't tell us anything - the current requirements of the camera are what matter.

[shockwave199 0]

Yeah after looking, cat 3 could have any number of pairs.

 

So my question- mine has three pairs and I wasn't sure if two pairs twisted would equal a thick enough amount to supply 12v4a over 30' to the camera. In the manual it says about the camera 12v+/-10% 50w. I've only ever read about four pairs and it being recommended to use three pairs twisted for power. I'm dealing with only two pairs left [one pair for comm/two for power] if I use the stuff I have at the moment- left over from telephone installation.

 

Thanks for your help guys. Much appreciated.

[dustmop 0]

This assumes the CAT3 is 22awg:

 

Wire gauge tables say that 22awg will drop 3.53 volts at 30 feet at 4A. 18awg will drop only 1.54 volts, which is within the 10% spec of the camera. Twisting the 2 pairs of 22awg will give you roughly 79% the cross section of 18awg (calculators and tables usually don't include 19awg, btw). So it MIGHTwork, depending on the camera and PSU.

 

If you CAT3 is 24awg, then it's likely not going to work at all.

[shockwave199 0]

Thanks for the reply. I ended up getting cat5e with four pairs- got some for free. I think three twisted pairs will handle the run- hopefully. I'll know soon enough!