JasonOfOz 2 Posted May 7, 2015 Share Posted May 7, 2015 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 4x1AThe 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 DCOur Engineer on site doesn't think splitting one of the -ve pairs to use for positive and negative will make anydifference 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. Quote Link to post Share on other sites
9651 12 Posted May 7, 2015 Share Posted May 7, 2015 (edited) 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, 2015 by 9651 Quote Link to post Share on other sites
james.wilson 741 Posted May 7, 2015 Share Posted May 7, 2015 60m is a long way on cca for that load Quote securitywarehouse https://www.securitywarehouse.co.uk Trade Members please contact us for your TSI vetted trade discount. Link to post Share on other sites
9651 12 Posted May 7, 2015 Share Posted May 7, 2015 proper cat5e all the way. Quote Link to post Share on other sites
james.wilson 741 Posted May 7, 2015 Share Posted May 7, 2015 i dunno if id of used just 1 cable at 60m even if proper cat5e Quote securitywarehouse https://www.securitywarehouse.co.uk Trade Members please contact us for your TSI vetted trade discount. Link to post Share on other sites
9651 12 Posted May 7, 2015 Share Posted May 7, 2015 not had any issues personally at that distance. Sometimes on a longer run we may supplement it with a .75 flex, but its rare Quote Link to post Share on other sites
JasonOfOz 2 Posted May 7, 2015 Author Share Posted May 7, 2015 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. Quote Link to post Share on other sites
james.wilson 741 Posted May 7, 2015 Share Posted May 7, 2015 you can send 24v ac up and convert to 12v dc at the camera end Quote securitywarehouse https://www.securitywarehouse.co.uk Trade Members please contact us for your TSI vetted trade discount. Link to post Share on other sites
9651 12 Posted May 7, 2015 Share Posted May 7, 2015 how messy is that though at the camera end? Ie how big is the converter? Quote Link to post Share on other sites
james.wilson 741 Posted May 7, 2015 Share Posted May 7, 2015 balun size Quote securitywarehouse https://www.securitywarehouse.co.uk Trade Members please contact us for your TSI vetted trade discount. Link to post Share on other sites
9651 12 Posted May 7, 2015 Share Posted May 7, 2015 not too bad then. Not something ive had to do tbh, but handy to know, Quote Link to post Share on other sites
james.wilson 741 Posted May 7, 2015 Share Posted May 7, 2015 https://www.securitywarehouse.co.uk/catalog/genie-24vac-to-12vdc-power-converter-p-3756.html Quote securitywarehouse https://www.securitywarehouse.co.uk Trade Members please contact us for your TSI vetted trade discount. Link to post Share on other sites
al-yeti 532 Posted May 7, 2015 Share Posted May 7, 2015 The Samsung bullets maybe dual powered, most of them are, same trouble I had so switched to ac psu's , so no need for convertor Quote Link to post Share on other sites
Adi 17 Posted May 7, 2015 Share Posted May 7, 2015 or variable psu Quote I really can't be ar**** with it anymore. Link to post Share on other sites
al-yeti 532 Posted May 7, 2015 Share Posted May 7, 2015 or variable psu Problem here would be current then , increase voltage won't give you increase current or have I mixed that up? Quote Link to post Share on other sites
james.wilson 741 Posted May 7, 2015 Share Posted May 7, 2015 no, increase the voltage it (dc) will half the current demand, ac theory is more log vs the lin of dc. DC is easier as its pure ohms law, Ac theory adds a little more ie impedance but its similar, ish Quote securitywarehouse https://www.securitywarehouse.co.uk Trade Members please contact us for your TSI vetted trade discount. Link to post Share on other sites
al-yeti 532 Posted May 7, 2015 Share Posted May 7, 2015 Ac theory always did confuse me lol Quote Link to post Share on other sites
Adi 17 Posted May 8, 2015 Share Posted May 8, 2015 As does alarms Quote I really can't be ar**** with it anymore. Link to post Share on other sites
JasonOfOz 2 Posted May 8, 2015 Author Share Posted May 8, 2015 Thanks everyone. Great advice, particularly about the AC. And you are right that the Samsung Bullets come AC/DC so that's good news. I'll be sure never to use CCA in future and just stick to good old fashioned copper. So can anyone answer my question about the correct use of the pairs for power? This is what is in place currently: - 1 pair for +ve DC - 2 pair for -ve DC I have since been told that this may be better: - 2 pair for +ve DC - 1 pair for -ve DC I would have thought that you would split all cables evenly: - 1.5 pair for +ve DC - 1.5 pair for -ve DC Can anyone explain why one option might be better than the others? (I'm getting a lot of "this is how we do it, but don't know why it works" - so wouldn't mind a little more explanation. Thanks Quote Link to post Share on other sites
james.wilson 741 Posted May 8, 2015 Share Posted May 8, 2015 Id go for the last option Quote securitywarehouse https://www.securitywarehouse.co.uk Trade Members please contact us for your TSI vetted trade discount. Link to post Share on other sites
Rulland 27 Posted May 8, 2015 Share Posted May 8, 2015 As James, what goes in should come out. Quote Link to post Share on other sites
mecsecurity 0 Posted August 28 Share Posted August 28 Analog CCTV cameras use coaxial cables, especially the Siamese cable for the wiring. Their videos are recorded via a DVR, which is a Digital Video Recorder where every single camera in a building is connected to the DVR. Once the system is properly wired and installed, it uses a distinctive mechanism for capturing videos. Quote Link to post Share on other sites
al-yeti 532 Posted August 28 Share Posted August 28 3 hours ago, mecsecurity said: Analog CCTV cameras use coaxial cables, especially the Siamese cable for the wiring. Their videos are recorded via a DVR, which is a Digital Video Recorder where every single camera in a building is connected to the DVR. Once the system is properly wired and installed, it uses a distinctive mechanism for capturing videos. Odd that , many use cat5 for analog aswell What you on about dude ? Or what's point Quote Link to post Share on other sites
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