CCTV Power Jack Adapter Wiring Standard

Is there a wiring standard for 12 VDC power plugs? Should the outside conductor be plus, minus, or there is no standard and could be either?

See http://www.amazon.com/2-1mm-5-5mm-Female-Power-Adapter/dp/B003MHUN7S/ref=sr_1_2?tag=gpse-20&ie=UTF8&qid=1292217153&sr=8-2

Best,

Christopher

There is no written-in-stone power-jack standard for pretty much ANY electronics... but with 12V barrel connectors, the vast majority of cameras seem to use tip-positive configuration (offhand I can't think of a single exception that I've come across).

I have seen ONE exception with some computer speakers I have, that use tip-negative... and I have an old Wacom drawing tablet that uses tip-negative (so old, it has a 9-pin serial connection). Most devices seem to be tip-positive though. There will usually be a diagram ON the device showing which polarity it uses.

All cctv cameras and cctv power suppliers I've used with barrel plugs, the outside of the plug is negative. The wire with a white stripe is positive.

All cctv cameras and cctv power suppliers I've used with barrel plugs, the outside of the plug is negative. The wire with a white stripe is positive.

Be careful with this, now, because this is a function of the power supply itself, not the camera, and can vary from one to the next. I just recently had to rig up a power supply and the only one I had, had no barrel plug... so I found another barrel plug (recovered from a removed camera), and found that while the plug connected the white wire to the outside of the barrel, the power supply itself used the white-striped wire for positive (and the diagram on it showed it was originally a tip-positive unit).

If you're splicing new barrels in, or snipping one off to just use the bare wires out of the wall-wart, always double-check polarity with your multimeter!

All cctv cameras and cctv power suppliers I've used with barrel plugs, the outside of the plug is negative. The wire with a white stripe is positive.

Be careful with this, now, because this is a function of the power supply itself, not the camera, and can vary from one to the next. I just recently had to rig up a power supply and the only one I had, had no barrel plug... so I found another barrel plug (recovered from a removed camera), and found that while the plug connected the white wire to the outside of the barrel, the power supply itself used the white-striped wire for positive (and the diagram on it showed it was originally a tip-positive unit).

 

If you're splicing new barrels in, or snipping one off to just use the bare wires out of the wall-wart, always double-check polarity with your multimeter!

+1, a number of wall warts I have come across have used the white stripe lead for negative, always check with a meter before you toast something expensive (some wall warts have ridiculously high unloaded/lightly loaded voltages, too, if you are using a very low current draw device, you could go outside it's voltage limits).