CCTV video and power over Cat5e

[ddobb]

I am a cabling project manager that has been put in charge of wiring my companies CCTV. These are simple black and white cameras that need 12VDC and .5ma. They run back to a computer and all recording is done on the hard drive. I have 12 cameras in total, with all <300'. It is very expensive to have an electrician come and supply power at each location so I want to send power from the MC. In the MC there are 2 large UPS supplies which would keep my cameras running should the power go out. I am also using 1 pair video baluns at each end to be able to run them over UTP. The baluns use pair 7/8.
Now here is my current layout: I have all the cabling to the cameras homerun to a Hubbell cat5 (old) panel in the MC. I then made solid core patch cables (10ft)that run down to the pc. I installed a 2 dc power distribution block made by Leviton next to the pc. It injects 13vdc 1.5ma and sends 12vdc ?ma to each camera. Each block services 6 cameras. So what I did was split out the orange and green to supply power and the brown is for the signal. I have the positve on the tip of orange and green and negative on the rings. I did this hoping to use the twist to help with noise. Now I tested this without using a patch panel a while ago and everything was fine, but now that I have it all in place and I can't even get a picture to come up. I thought I might not have enough amperage so I went to good ole radio shack and got a 13vdc 3amp injector and hooked it up. Bam, now I have a picture but it locks up after 1 sec of motion. If anyone has ran a config like this please let me know. The owner currently thinks that this thing is up and running so I need a solution that won't involve pulling a series 6 line to each location. &quot;Hey what are you doing in the ceiling&quot; is not what I want to hear.

Thanks,
Dirk Dobbins

 

[Servamatic]

Not sure if this is the problem, but for starters, you have power run in parallel on unequal length conductors, which is not advisable, nor allowable for nominal voltage.
You could run the POE on 1 pair only which most POE we do is.
Run the video on the tightest twist pair, generally blue.
Run + on tip colors and - on rings per standards. Use pins 1 & 2 or 7 & 8, for power that gives you some separation from the video in a jack.
Not sure if this will solve the problem, but it should help.
IP cameras would have been a better way to go with POE.


Richard S. Anderson, RCDD

http://www.smartbuilthomes.com

 

[Servamatic]

Just running some basic calculations...

If you need 12 V at the camera over 24 AWG wire 200' you would need roughly a 14.5 V power supply as well running it over a single pair. You have roughly a 2.5 V loss due to voltage drop.

Richard S. Anderson, RCDD

http://www.smartbuilthomes.com

 

[ddobb]

Thanks for your help. I wanted the IP cameras and I know that Anixter is releasing some very nice ones. Sometimes the powers that be dictate spending and figure you are a tech so make it work. I will try moving the video to blue and only using one pair for power. My thought on the power was to get a little more gauge to lower resistance for the distance. I hadn't considered the twist/length to be large enough to create problems.

 

[Servamatic]

I know what you mean about &quot;doing what I can with what I got&quot;... Good luck, let me know what happens.

Richard S. Anderson, RCDD

http://www.smartbuilthomes.com

 

[wires]

Four possibilities come to mind:

1. Voltage drop. Check the voltage at the camera with a voltmeter. If it is too low to run the camera then use 3 pairs for voltage and one pair for video. DC is not affected by &quot;unequal length conductors&quot;. If you still cannot get enough voltage with 3 pairs then start increasing the power supply voltage at the &quot;MC&quot; end. Be aware that you don't want to &quot;over voltage&quot; any cameras on the shorter runs.

2. Some equipment cannot share power supplies. We installed some Panasonic cordless system phones using a shared regulated supply and fuse block. The common ground drove them crazy. Once we used one power supply per phone all was well.

3. You said it all worked before the patch panel was installed. Possibly the patch panel is defective or you horked the connections somehow.

4. Undersized power supply. I am somewhat curious about the &quot;12VDC and .5ma&quot; since .5ma is .0005 of an amp which seems low for a camera. You also have a &quot;13vdc 1.5ma&quot; power supply which would have an EXTREMELY low current capacity. If you have 12 cameras that draw .5ma then you power supply would have to be capable of at least 6ma to power them all. My guess is there is some confusion in you current numbers. One possibility is that you don't have a power supply with enough current capacity. If the cameras actually draw .5a (500ma, not unheard of for a older camera) then you would need at least a 6 amp power supply to run them and considering voltage drop using 3 pairs a 15vdc power supply.

What is the voltage at the cameras?

What is the voltage at the power supply?

 

[fs483]

Maybe it's too late but if you bring all the cameras in the MC and have them all connected at once to your distribution block and then you'll see if the power supply works with all your cameras at once. If it does, then maybe start reconnecting one camera at time at the remote locations to see when you start loosing video.

anthony

 

[Bobg1]

I would tend to agree with wires on this one.
Sounds like you don't have the correct size power supply.
You need to double check the power requirements of the cameras.

If they are what you say at .5ma, your 1.5ma power supply will only be able to operate at best 2 cameras.
Yes I know if you take 1.5 divided by .5 it will give you 3
BUT with line loss and the type supply he probably has, I wouldn't push it that hard.

 

[Servamatic]

The Leviton DC power supply is 1500 ma, not 1.5 ma. at 13VDC
Part #48212=DCS

Richard S. Anderson, RCDD

http://www.smartbuilthomes.com

 

[ddobb]

Thanks to everyone for the help. Much appreciated. I'm in the process of purchasing a larger power supply and pulling rg6 to all cameras for signal. The big part was having centralized power. Thanks

 

[daronwilson]

You should have no problem with RG59 in that installation, if you get siamese wire you can get the two power wires with it and make one pull to each camera. A good power supply for your installation would have several fused outputs so you can individually fuse each power circuit.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com