Slightly off topic wire question

[Randall]

I need to run maybe 30' of 12v run from an outdoor mounted security camera thru my attic and then down through my garage ceiling to a wall mounted AC adapter. Rather than buy a reel of zip cord or something, can I use a length of Cat5e solid copper 24 gauge comm cable that I have on hand? If so, it is four pair wire, would I use one pair for pos and one pair for neg? Or would it better to use two pair for each?

[olddawg]

I need to run maybe 30' of 12v run from an outdoor mounted security camera thru my attic and then down through my garage ceiling to a wall mounted AC adapter. Rather than buy a reel of zip cord or something, can I use a length of Cat5e solid copper 24 gauge comm cable that I have on hand? If so, it is four pair wire, would I use one pair for pos and one pair for neg? Or would it better to use two pair for each?

12v AC or DC? If it's AC use the wire they use for 12v yard lights. I wouldn't run 30' for 12v DC. If you have to use a wall wort that puts out 12v DC, you may want to install an AC outlet in your attic. Or.. get a transformer run the lighting wire, and rectify it at the end of the run.

[Randall]

It's 12 volt DC, and my attic is pretty much inaccessible. My first choice would have been to install an outlet, but that ain't gonna happen.

[olddawg]

It's 12 volt DC, and my attic is pretty much inaccessible. My first choice would have been to install an outlet, but that ain't gonna happen.

Running a 30' DC run MIGHT be ok. I would hook it up somewhere else before installing it. Measure the voltage at the end of the run and see how everything works. If it's fine then run the same wire. I would still use the wire they use for 12v outdoor lighting.

[dstrat]

Voltage Drop Calculator
will give you the info you need I think.

main thing is the current requirement of the device and wire size.

[Enzo]

I suspect the current demand is small. Use the same wire they use for like doorbell buttons.

[eschertron]

30 feet of bell wire will run you about 7 bucks from the big box stores Home Depot for example. Not endorsing, just citing my source.

[Randall]

what does that 20g bell twisted pair have over a double 24g comm twisted pair? The AC adaptor is rated at 12vdc / 2 amps. Camera has night vision and wi-fi.

OK, answered my own question. According to that voltage drop calculator, at worse case, the 20 gauge pair drops 0.61v, and the four conductor 24 gauge drops 0.77v. I think the run will come in a little less than 30', and I doubt the camera is drawing the full rating of the adapter, so I think it will be OK.

I will run the camera on my variable DC power supply for a while and see how it likes 11 volts.

[Chuck H]

What the camera has for modern features that include any special resolution, sensory, matters little WRT the DC supply. See post #5 for the relevant information. 20g is obviously going to have less voltage drop than 24g. Would 24g drop too much voltage for your required length? You'll need to know the current consumption of the device to determine this, but with that the info is in the link.

[bob p]

https://en.wikipedia.org/wiki/Power_over_Ethernet

[olddawg]

I recommended the 12v outdoor lighting wire because it is large gauge solid core, fairly stiff, but still slippery and pliable. It's cheap. Available everywhere. It's very easy to shove through holes, up walls, and around corners.

[Randall]

All good information and advice, thanks. I put the AC adaptor on my variac, and depending on what it is fed, it either puts out 0v or 12.5v unloaded, so it's well regulated, which suggests the camera may be finicky with respect to voltage. So I rethunk my approach. The adapter cable is 10' long, which was enough to snake down from the peak of the attic and through the garage ceiling over a couple feet where I installed an electrical duplex box fed by a 20'extension cord neatly along the ceiling/wall edges to the closest outlet.

Problem solved.