Cat5 distance for 12v cameras

I have boxes of cat5 in the garage from my cabling days.. so instead of using the cheap siamese cables that came with a kit i've got i'd like to use cat5 with baluns instead since this would be much cheaper than ordering a spool of siamese 18/2.

Given that the 24awg conductors are smaller in size than the 18awg of siamese, how far can I expect to go with cat5 cable on 12v 500ma and 12v 750ma cameras?

Given there are 8 conductors in cat5, can I use 3 conductors for + and 3 for - plus the 2 for video?

The longest run will probably be around 150ft.

I have boxes of cat5 in the garage from my cabling days.. so instead of using the cheap siamese cables that came with a kit i've got i'd like to use cat5 with baluns instead since this would be much cheaper than ordering a spool of siamese 18/2.

 

Given that the 24awg conductors are smaller in size than the 18awg of siamese, how far can I expect to go with cat5 cable on 12v 500ma and 12v 750ma cameras?

 

Given there are 8 conductors in cat5, can I use 3 conductors for + and 3 for - plus the 2 for video?

 

The longest run will probably be around 150ft.

The factors missing are the actual output voltage of the power supply(ies) (regulated vs. unregulated), and how much loss the cameras can handle before they drop out...

But in general, you should have no problem at 150', even using two pairs.

According to this calculator, and assuming a regulated output of exactly 12V: http://www.netkrom.com/voltage_loss_over_cat5_calculator.php

... with three pairs for power, you should see a loss of about 0.6V for the 750mA camera, and 0.4V for the 500mA camera.

If the power supplies are not regulated, you'll probably be seeing closer to 16VDC out of them, and losses will not be a factor, even using just two pairs for power.

Some cameras can tolerate lower voltages as well - the CNB dual-voltage cameras, for example, list "12VDC/24VAC" but will actually take anything between 10V to around 30V, AC or DC, because they rectify and regulate the power internally.

Thanks for your response. I'm sure the supply is regulated as it's a wall wart style supply.

I read your other post here: viewtopic.php?f=6&t=26380

and found this here:

http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=84.22&voltage=12&phase=dc&noofconductor=3&distance=150&distanceunit=feet&amperes=.70000&x=61&y=16

I was able to determine that in this scenario that 3 pairs of cat5 is better by a very small margin that 18awg from siamese cable with the calculator that I found, but different in the calculator that you found.

I sure hope that the 12v camera will run on approx 10.2 - 11.4 like you mentioned.

The calculator you posted a link to gives different results from the one that I found.

It's a no-name camera from aposonic..

http://www.aposoniccctv.com/index.php/camera/fixedlens/193

and this camera as well

http://www.aposoniccctv.com/index.php/component/content/article/192

This is stuff I should know since i've built small dc power supplies before.. I guess sometimes I don't allow myself to mesh one hobby into another. The differences are that I'm able to use any size cable I want to with the type of stuff i've used it for.

I found another one that puts the drop at 750mA at 0.9V, too...

Suffice to say, this is another reason I like a GOOD TDN camera like the CNB Monalisas, rather than something that has to rely on IR at night - the VCM-24VF draws a max of 180mA at 12VDC, half that at 24VAC.

I totally understand that! That makes those cameras extremely versatile in their ability. Worst case scenario is I run power to 1 or 2 of the cameras from a closer source.. no big deal.

voltage drop calculators use different theoretical resistance for the cables, which is why they vary slightly. the NEC (National Electric Code used in the US) has a table listing how much resistance per 1000 feet of wire each gauge should be. This table seems to change with each release of the code book. if you ever happen to look at a data sheet for a specific type/brand of cable, it'll list it's own resistance per 1000 feet, often times it's lower than the NEC. The calculator uses this figure to calculate how much resistance you should expect from your specific length of cable at a specific gauge.

In short, don't worry about the minor differences. Neither calculator is wrong, the actual formula used to calculate the final answer is identical, the resistance variable is slightly different based on what standard numbers they're going off of to guess the cable resistance.

Keep in mind that temperature can play a (minor) factor as well... few if any of the online calculators take that into account.

None of them are meant to be anything but approximate anyway.