ceeceetv 0 Posted February 17, 2010 Hi, I'm doing a job for a friend (as a favour) who has recently purchased a shop that went broke. The previous owners ripped out most the CCTV system (including power and DVR). They have left BNC and power cables along with 2 outdoor IR domes. I am fairly happy the existing BNC cables should be ok, but what has puzzled me is all the power cables have 4 cores (all various colours) but have been made into 2 by twisting together. Not to sound stupid, but I'm assuming they are live and neutral. Is there any reason why 4 cores twisted together have been used?? I've not done much CCTV installation so any help / guidance would be appreciated! Share this post Link to post Share on other sites
Soundy 1 Posted February 18, 2010 Are those solid 22ga. cores? If so, chances are they used "Station Z" wire, which is common for alarm installs. The reason for twisting them together is that it gives better capacity (lower voltage drop, higher current capability), although for short distances that's really not a concern. It also provides some redundancy, so if one wire breaks, you still have the second one of that pair. The reason for using it may simply be that they have lots of it - if the system was put in by alarm installers, for example. We usually use this instead of 18/2 because it's more versatile - you can split the pairs out and run video over one, for example, and it's good for access controls, smoke detectors, intercoms, etc. - so it saves over needing to stock two separate kinds of cable. Chances are the system they had in place used 12VDC cameras, so one pair would be for + and one for ground... you can open up the IR domes to see what they used and wire the other end to power as needed. With 24VAC, there is no polarity, so it doesn't really matter which is which. We generally use yellow and red together for 12VDC+, green and black together for ground. Share this post Link to post Share on other sites
