how to wire an analog camera?

[TLCNORM]

You can buy premade wires off eBay as well. They include an RCA cable for the video feed, and a power cable. You run the cable from your camera to your wiring closet/dvr.....your wall wart plugs in near your DVR and it's simple. No expensive baluns and custom wire fabrication

You can get them up to 100 foot lengths I believe. This one is like $15 including shipping:

Just be careful with the ebay ones. I got a camera, power supply and 100'cord, I was unhappy with the cord, it has a really thin gauge power cord, and the power supply was bad. I didn't pay a lot for the whole package so I am not that unhappy. I guess you get what you pay for. The camera is only used to watch if the baby is awake or sleeping not for security.

 

[znelbok]

Something else might be worth mentioning here as well. I'm guessing some outdoor cameras require more current capability, therefore a large current capable supply is needed. One thing to keep in mind (as I'm sure most members here already know) is to be cognizant of the output's fuse method of the parallel "multiple" legs.

For instance in the first example below, the overall DC output is fused and the output is fed to three different sources. The problem is if source 1 shorts, the maximum current is fed down that leg (that the fuse will allow). Since your fuse size is probably comparable to the overall output amperage capability it may be more than desired (depending on the device, wire size used, etc...).

It's probably better to individually fuse each leg (near the distribution point) and size the fuses to each load's needs (second example below). This is the advantage of using a power distribution module such as the Elk's, but if its (current) capabilities are not large enough, you may need to implement your own protection scheme.

It is called discrimination and all circuits should be designed to discriminate properly - wether you are using circuit breakers or fuses on DC, low voltage or high voltage.

Don't forget a fuse/circuit breaker is there to protect the cable, not the device (hence the cable must be able to handle the short circuit current for the time period before the protection device activates)

As an example, a 250mA fuse will discriminate correctly with a 100mA fuse downstream.

So in the examples above, you could have say one 250mA fuse with 5 x 100mA fuses. Don't be fooled by the maths. Just because the 5x100ma is 500mA does not mean the 250mA will blow. You don't need to rate the fuse to the device, just as long as it exceeds the device rating and/or total current draw.

So 5 cameras at say 40mA each, protected by their own 100mA fuse, which is all protected by a 250mA fuse will work fine and any short circuit on the cables to the cameras will only blow the 100mA fuse and leave all others OK.

The fuse manufacturer should have a table showing which fuse discrimination.

Proper power distribution design will ensure that you never have the wrong fuse/CB tripping.

Mick