longest run for 12vdc without drop out

[curtley 0]

Does anyone know what is the longest run you can run 12vdc using RG59+2core and cat 5 using baluns with out drop in voltage?

[VST_Man 1]

noticable drop? r u talking tenths or single digit drops? technically, voltage starts to drop in the first 25ft. but for a camera to feel that pain it goes to about 250ft. before you see any issues.

 

ac voltage is best for anything past 250ft.

[securitymonster 0]

It will also depend on the gauge wire used, some Siamese RG59 is 22 and some is 18.

 

I would say VST has a good number, 250 is accurate!

[sajaan458 0]

Yes, I have noticed the samething as VST with RG59U with 18G wire I started noticing the difference going over 200ft-250ft. Far as CAT 5 baluns I wouldn't recommend or use it to carry power and even if you do use it for power then you can't go over 200-250mA on DC12 and I don't think you can use Cat 5 baluns to carry AC power... Regards... Sajaan

[WirelessEye 0]

It does depend on the power consumption of the 12VDC equipment and the wire gauge. With 18AWG and a 2amp peak draw (2.3 amps being the highest you should go for 18AWG), you shouldn't go beyond 38 feet as you will drop below 11VDC at anything further.

 

At 250ft and 18AWG with a 2amp load, you would have 5.42VDC at the end of the line.

 

If you are looking at power over ethernet, you are even worse off. 9 feet maximum for a 2amp load just to keep you above 11VDC.

 

Most 12VDC devices can operate between 11VDC-13.5VDC range.

[captainJ 0]

ac voltage is best for anything past 250ft.

 

how significant of an improvement with AC vs DC?

[VST_Man 1]

good enough to use AC if distance is over 250 ft. If beyond 250ft. use 24VAC or a 28VAC power supply, depending on the distance. I currently run 24VAC beyond 500ft. with no problems. Basica day night cams...if you had to run a PTZ you'd most likely have to power locally because that distance and amps carried won't work very well. Always consider the total amps required. ie. camera, IR, heater blower, ect. It's easy to get it up and running during the day but when the sun drops and the IR comes on along with the heater blower the camera has a heart attack for more power.

 

when using CAT5 I double up on a pair for the power.

[cachecreekcctv 0]

You can always increase the wire gauge to attain the desired voltage. Just because we normally use 18 AWG , doesn't mean someone can't use 16AWG, or even 14AWG, to attain a voltage drop of less than 5%. Find a "voltage drop" table, which will show ; amp draw, wire length,wire size, etc. to see what you need. You might even make the initial wire run larger, then find you can use the smaller 18awg from a terminal point to the actual camera itself.

[securicorp 0]

Heres a trick I used to fix a messed up install I was called on to rescue.

 

Cat5 was used to cable video and 12v DC to some cameras just over 500ft (200m) away. Obviously this was not working and the customer was stressing to get this fixed.

 

I used a 24v AC 10A power supply with fused outputs by Pelco. I doubled up 2 cores each in the Cat5 for power.

 

At the camera end, I used 24v AC to 12v DC stepdown transformers available from Genie.

 

Problem Solved!

(OK, that was a risky move with AC with video down Cat5 but it worked)

[cctv_down_under 0]

My installer has run cat5 for a site I am doing with 50 odd cameras, some of the runs are over 150 meters and I suppose this is why he did it (wish I knew I would have just used the XF camera), he is using a passive balun at the camera end and a rack munted recieving station (also passive) that recieves 4 x cat 5 and converts to coax, I am concerned with running 24V AC on such small wires and within the same sheath, can there be some issues with this becasue some of the cameras will draw at least 500ma?

[securicorp 0]

My installer has run cat5 for a site I am doing with 50 odd cameras, some of the runs are over 150 meters and I suppose this is why he did it (wish I knew I would have just used the XF camera), he is using a passive balun at the camera end and a rack munted recieving station (also passive) that recieves 4 x cat 5 and converts to coax, I am concerned with running 24V AC on such small wires and within the same sheath, can there be some issues with this becasue some of the cameras will draw at least 500ma?

 

I was worried when I tried it too but it all worked out fine. If you have any spare PSU's such as a 24v AC, get some Cat5 and a stepdown transformer and see how long a cable run you can get (use a balun for video).

 

You can even get Cat6 STP cable which means each twisted pair is foil wrapped for extra protection. I hear the twisted pair is better at noise rejection than coax but I still need to take time to compare this.

[securicorp 0]

Oops, forgot to mention that when you convert 24v AC to 12v DC, you can consider the amps double at the camera end. We used 24v AC 10A power supply which should give us close to 20A in DC so there was plenty capacity.

 

Correct me if I'm wrong on the amps conversion

 

Securicorp

[securicorp 0]

Oops, forgot to mention that when you convert 24v AC to 12v DC, you can consider the amps double at the camera end. We used 24v AC 10A power supply which should give us close to 20A in DC so there was plenty capacity.

 

Correct me if I'm wrong on the amps conversion

 

Securicorp

[cachecreekcctv 0]

In theory perhaps. There is a reason that power companies transmit electricity in AC form. Another reason for 3-Phase power and not 1-phase being transmitted. Top of power lines (residential areas) are normally 12,000 volts. You would always want to transmit the highest voltage possible in AC form, then step-down at the end to the lower voltage, and DC current. When you run AC through the power supply, and rectify it, you lose current through heat, etc. In my job, I deal with 480VAC 3-Phase dozens of times a day, so when I get to work on small DC power supplies, I take the gloves off and stop sweating. If you look back in History, Edison wanted DC for us, Tesla/Westinghouse wanted AC , Edison lost, and we never looked back.