PC Based Surveillance DVR - Camera Power?


Old 04-23-06, 09:44 AM
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PC Based Surveillance DVR - Camera Power?


I have a small medical clinic that I wish to have off hours video monitoring of doorways and hallways and daytime monitoring of reception/waiting room area.

The big question in setting up one of these systems is, how do we power the cameras? There seems to be a plethora of 4+ channel capture cards and software for live monitoring and DVR motion sensor recording, but I can't find information on camera power options. Does the camera require an outlet at it's location? Are there cameras that are powered through the PC itself?

We don't want to use IP cameras or USB cameras and from what I can tell, and I can be completely wrong, the cables that have AV/Power allow you to hook a wall wart at the end of the run meaning all four cameras are plugged in at the same spot at or near the PC?

Thanks for any input/advice.

Old 04-23-06, 12:06 PM
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I recently installed a 4 Channel DVR in my home to keep an eye on the out side. Although I am not a expert, I have installed temporary video surveillance systems around the world.

Most security systems use what is called 18/2 Siamese Cable to provide video and power to from/to the camera.

What is a 18/2 Siamese Cable?
This means that there are 2 wires of 18 gauge. This is the wire that the cable uses for power. One is considered negative and the other positive when connecting to the 12 volt power supply.

This is the standard notation for power cable. The smaller the number the heavier the gauge of the wire and the second number represents how many wires of it are being run.

For example most homes use 14/2 and 12/2 with ground. 12 gauge wire is rated at 20 amps max load. An electric dryer will use 4 gauge wire due to the heavy amp load. Thermostat wire is 24 gauge since it carries only 24 volts and almost no amperage

Now if you buy a kit system most provide a card, software, a camera for each port, and between 30 and 50 feet of cable. The cameras should also come with a power supply that will be used to power each camera.

Here is one link to what I am talking about. I am not endorsing any site but it was the 1st I google that show shat I am talking about.

I hope this helps you...

Old 04-24-06, 06:19 PM
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First, check to see what power your cameras require. Most are 12 volt but check make sure they all need the same power if you connect them to one power supply.

You can use a small power supply (similar to a cell phone charger) for each camera or you can use the Siamese cable as mentioned and power all you cameras from one power supply near your DVR. Since you have to run a coax cable from each camera back to the DVR the Siamese cable and central power supply can make a lot of sense. This also allows you to plug your DVR and the camera power supply into a standard computer UPS (Uninterruptable Power Supply) so your cameras will keep working even when the power goes out.

One thing to keep in mind is that cameras with built in IR illuminators can suck a lot of power. 12 volts does not like to travel far so you will have to keep your cable runs to a minimum and possibly go to a larger size wire. Watch out for pre-made coax/power cables. Most use very small power wires so be careful when using them to feed in IR camera.

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