POE Camera Loss

AceReif

Member
I installed 4 PoE Cameras to and outside location about 400' from the head unit and had substantial video loss is there anyway to calculate PoE VD or a way to boost said power?


Thank you for your time
AceReif
 

Dennis Alwon

Moderator
Staff member
Although the op is not an electrician the question is really not electrical per se so I am allowing it.
 

ron

Senior Member
The normal limit for Cat 5/6 cable is 100 meters. Not only that, but you have to think of voltage drop on those very small wires and how much power capacity POE has available. Some POE sources / switches only have a few to maybe 10 watts available.

I don't know how to calculate it, but 400' for 4 POE cameras doesn't pass the smell test for me.
 

GoldDigger

Moderator
Staff member
Video loss. Can you be more specific?
Poor camera performance could result from low voltage. A quick test for that would be to put a POE feed right at the camera, using an AC extension cord if necessary.
If that does not help, then the problem is data losses in the cable.
There are limits on how far a CAT 5 Ethernet run can go without a bridge or switch. I would not be surprised if 400 feet is too far, as Ron said.
The reason for that limit is not voltage drop but signal and timing issues.
Also, are you running 4 separate CAT 5 or are you placing a bridge or switch linking the cameras? You cannot just parallel the cameras via hard wiring.

Sent from my XT1080 using Tapatalk
 
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grich

Senior Member
Agreed. You are too far out for Ethernet to work reliably, POE or not. There are repeaters you can install mid-span, but you'll have to power them, of course.
 

cadpoint

Senior Member
This is a classic VD problem, it doesn't matter be it AC or DC usage!

If one needs a sum of workable Power at point of usage, one has to supply the correct
size of wire for it to correctly be there in toto.

One can get an idea of this from reading this active thread.

DC voltage wiring in home
 

Jacob S

Senior Member
Like others have said, the standard for copper ethernet interconnects is 100 meters. Although in many cases, you can go over and have no issues, IP cameras often use UDP to transmit live video, where you give up the error checking and correction capability of TCP. This means, that any dropped packets, or chunks of dropped packets, will result in a noticeable video loss or interruption.

Using high quality Cat 6, connectors, and network hardware may alleviate the problem, but the only real solution is to run fiber or add a switch somewhere in the span.

This is addition to any VD problems others have already mentioned. PoE devices can be PoE or PoE+, which relates to the amount of power a port can source or how much a device requires to operate. Make sure you have the proper PoE injectors or switch for the cameras you are using.

Let us know what you find.
 

Rampage_Rick

Senior Member
Power over Ethernet (802.3af) allows for voltage drop over the standard ethernet distance of 100 meters / 328 feet. The standard is for 48 volts DC, at a maximum current of 350 mA. Assuming 24 ga conductors, the voltage drop over 328 feet at 350mA is 2.95 volts. That's for a standard 2-pair Type 1 connection. There's also a high-power Type 2 standard that uses all 4 pairs, allowing up to 600mA load (2.53 volt drop at 600mA / 328 feet)

Note that there versions of PoE out there that do not comply with 802.3af. Some operate at only 24 or 12 volts. (I find this alot with Ubiquiti radios) Obviously these are more suceptable to voltage drop. Sometimes it's possible to use 802.3af compliant injectors and splitters to overcome this. The injector puts 48V into the cable, the splitter takes it out and reduces the voltage to a lower level (usually 12v)

The easiest way to test would be to find a way to power the camera locally (wall wart and a bunch of extension cords) If that solves the problem then you need to address the voltage drop. However, I suspect that the main issue is the excessive ethernet length. If this is in fact real PoE, I would suggest a PoE extender like the Axis T8129. Doesn't correct for voltage drop, but it is basically a 2-port network hub that repeats the ethernet signal.
 

AceReif

Member
thank you all for your help and comments. i work for a low voltage company and i remembered seeing max cat5e length at 100 yards and couldn't find anything on how to calculate VD for that small of wire. this job wasn't one i bid or set up i was just a grunt on the ground and wanted to try and educate myself on how to prevent this from happening if i ever become more than the grunt on the ground. im just starting out in the electrical field and love it so far thank you all for all the hard work you do and tolerating apprentices "dumb" questions like this one
 

GoldDigger

Moderator
Staff member
Glad you are interested in learning more! The calculators and tables for VD may not go that small, but the equations behind them do and you can get the ohms per 1000' for that wire to plug into the equqtions.

Tapatalk!
 
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