dsw Posted March 30, 2006 Share Posted March 30, 2006 Sorry to be asking another question but we are currently quoting a job with 2 ptz speed domes and 2 body cameras. Bodys are 24v and will be powered from central psu. We would like to power the ptz's from the same source but i know that the distance to the ptz to psu could be an issue as they are more sensitive to voltage loss. PTZ's would be around 50-80meters max from psu. This is probably too far but is there a recommended distance from psu with ptz's. It would save us having to get a qualified spark to put fused spurs in but will have to do that if its the only option. Paul Link to comment Share on other sites More sharing options...
esp-protocol Posted March 30, 2006 Share Posted March 30, 2006 You need to double check the IEE regs for exact figures, and installation factors etc, but as a worst case, if you assume the mv/A/m for 1.5mm cable to be 30mv, the cable length to be 100 m, you need to know the maximum current draw from both ptz's. Then basically, 0.030(mv/A/m) X 100 (m) X Current (ptz1 + ptz2) = volt drop So if each PTZ draws .75 amps then .03 X 100 X 1.5 = 4.5 volts This is a worst case rule of thumb assuming the whole load is at the end of the cable. If you use 2.5mm cable, the mv factor is around 20mv/A/m. Link to comment Share on other sites More sharing options...
ian.cant Posted March 30, 2006 Share Posted March 30, 2006 I do a lot of CCTV work on a large supermarket where the 24 ac domes are powered from one source. I am supplied with .75mm 3 core flex, some runs are very short some are way over 100mtrs, never had a problem yet! Link to comment Share on other sites More sharing options...
Guest Trulloman Posted April 11, 2006 Share Posted April 11, 2006 Dont forget to allow for when the heaters kicks in, on a long run it could take approx 5-6v drop. Link to comment Share on other sites More sharing options...
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