Hi Everyone,

 

Would be great to get your thoughts on this one.....

 

 

We are currently using CAT-5 (CCA) to supply some analogue cameras with baluns.

The original PSU specified for the project is the Vista 12VDC 4x1A

The longest cable run is 60m but we are having issues on much shorter runs.

Cameras being used are Samsung Bullets w/ IR LEDs that draw 790mA max. current.


During testing today, we were only getting 9V at the camera end / 12.2V leaving the power supply.

At the moment the cabling has been configured:
 - 1 pair for video
 - 1 pair for +ve DC
 - 2 pair for -ve DC

Our Engineer on site doesn't think splitting one of the -ve pairs to use for positive and negative will make any
difference at the camera end. Can anyone explain why?

I'm not a sparky so don't really understand the physics of it, but naturally would have thought more cores would supply more power.


ps. we are changing the PSU's anyway but still want to optimise the power to the cameras.

CCA

 

Basically its ****, and gives a much higher resistance than standard copper cable. Measure the resistance on the runs, you'll be surprised (maybe)

 

We tend to fire the video down a twisted pair (browns), then power down the two others. So thats the blues twisted together, and the oranges.

Edited May 7, 201510 yr by 9651

60m is a long way on cca for that load

proper cat5e all the way. 

i dunno if id of used just 1 cable at 60m even if proper cat5e

not had any issues personally at that distance. Sometimes on a longer run we may supplement it with a .75 flex, but its rare

Just plugged in the numbers into a voltage drop calculator.

 

The difference in resistance values between CCA and Copper are significant, but it also shows very similiar levels of voltage drop, so you're probably right about using CAT-5 over this distance for power.

 

Putting this down to 1st time rookie specification mistake.

 

We'll try AC tomorrow.

you can send 24v ac up and convert to 12v dc at the camera end

how messy is that though at the camera end? Ie how big is the converter?

balun size