danlad1980 Posted January 21, 2011 Share Posted January 21, 2011 hi all. here is one for you, what would you say is the maximum mA you can fun down a length of cat 5 approx 50 meters. I have had many people say different things lol Link to comment Share on other sites More sharing options...
Cubit Posted January 21, 2011 Share Posted January 21, 2011 hi all. here is one for you, what would you say is the maximum mA you can fun down a length of cat 5 approx 50 meters. I have had many people say different things lol single core or multi? and around 500mA ish Link to comment Share on other sites More sharing options...
danlad1980 Posted January 22, 2011 Author Share Posted January 22, 2011 using one twisted pair as one wire. i myself have said nothing over 500mA. I have heard of people trying to ram 1amp down it. Link to comment Share on other sites More sharing options...
Cubit Posted January 22, 2011 Share Posted January 22, 2011 using one twisted pair as one wire. i myself have said nothing over 500mA. I have heard of people trying to ram 1amp down it. Well that is also correct then. Single core is just over half amp so doubling up... Link to comment Share on other sites More sharing options...
james.wilson Posted January 22, 2011 Share Posted January 22, 2011 what voltage? I wouldnt expect much voltage to be there over 50m at 1/2A to be fair securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
Cubit Posted January 22, 2011 Share Posted January 22, 2011 what voltage? I wouldnt expect much voltage to be there over 50m at 1/2A to be fair Ah, that's not the question though, is it. Probably drop around 1V over that. Link to comment Share on other sites More sharing options...
Kenzo Posted January 26, 2011 Share Posted January 26, 2011 The simple answer is stick a 1 amp psu on it and it will work! The not simple answer: Is it AC or DC as AC resistance can be many times higher than DC resistance. If it was just down to cable gauge then CAT5 cores are typically 24 Gauge which is approx .5mm and could theoretically carry 3amps DC but as James said at what voltage. Its all about the voltage drop. If you connect a battery at 12V DC to one end of 100 metres of CAT5 you will measure 12VDC on the other end but apply a load and see the voltage drop kick in. If I remember my electronics: if you double up the wire you reduce the gauge by 3. Two 24 gauge wires = one 21 Gauge. By doubling the wires you go from aprox 0.5mm squared to 0.7 mm squared cable. So doubling the cores does not double current carrying capacity. If its AC it's better to keep the wires in twisted pairs so that the two wires carry equal but opposite currents. In true DC better double up each twisted pair to make one core. If its AC at what frequency. If its DC is it regulated or switched mode psu. If regulated what is the ripple. I could go on and on but the simple answer will work. Link to comment Share on other sites More sharing options...
james.wilson Posted January 26, 2011 Share Posted January 26, 2011 i would expect a significat drop at .5A over 50m on single cores. Id say in the region of 4-6v drop. But im basing that on intruder cable. securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
PeterJames Posted January 26, 2011 Share Posted January 26, 2011 V over I = R If you measure the resistance and you know the current drawn you can work out the voltage drop. Much better to power locally and just leave the cat 5 to send the picture Link to comment Share on other sites More sharing options...
arfur mo Posted January 26, 2011 Share Posted January 26, 2011 Ditto Peter. alarm cable is rated @ 1amp 50 volts per core (which is a maximum), but try getting 12 volts at a dual-tec pulling 25ma over 100 meters of cable - you wil be there a while looking for it, and cameras tend to pull a lot more than 25 ma. my rule of thumb is 30 meters max to power a camera over Cat5e, you might get further but unreliablity creeps in, and don't forget the effects of temperature on the current drawn by the camera if it has heaters. Arfur If you think education is difficult, try being stupid!!!! Link to comment Share on other sites More sharing options...
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