voltage drop in POE applications

[trauts14]

with cctv cam deployments voltage drop can be an issue and using larger gauge wire can reduce the problem. how is voltage drop addressed when using ethernet cable for a run that is 200 feet for example...or a longer distance?

 

[Kawboy12R]

Use 12v at the camera after converting whatever actually arrives which started out at 48v from the switch/injector. It won't drop to below what'll still work at the cam if you stay within specs.

 

[nayr]

PoE is rated to 300ft, along with ethernet.. it does this by injecting a higher voltage (48vdc) then the camera regulates it down to 12v and applies it to the 12v rail.. just like they transmit power to your house at a higher voltage.

as long as you use 23-24awg cat5e/cat6 it'll be fine if you stay within specs; if you wish to go further you use a PoE extender to get a lil more distance or use 24vac

 

[trauts14]

gotcha. thank you all for answering my question.

 

[tangent]

with cctv cam deployments voltage drop can be an issue and using larger gauge wire can reduce the problem. how is voltage drop addressed when using ethernet cable for a run that is 200 feet for example...or a longer distance?

Ethernet is rated for 100m or 328' the PoE specs 802.3af and 802.3at are too. As long as you aren't using some form of passive PoE or tiny cables (awg > 24) you'll be fine.

The length/quality of the cable have some impact on how efficiently power is supplied. PoE+ to a power hungry PTZ is where this sort of thing starts to matter more.

 

[alastairstevenson]

Interestingly, Hikvision have introduced an out-of-spec extension to PoE run length on the 76xxNI-Ix I and K series NVRs in the 3.4.91 firmware.
There is a setting that drops the ethernet link speed to 10Mbps which claims to extend the usable length to 250m Cat5e/300m Cat6.

[POE Configuration]
(1) I and K series POE NVR supports extending POE transmission distance from 100M to 250M
with cat5e cable or 300M with cat6 cable;
(2) The capacity of POE port will be changed from 100Mbps full-dup to 10Mbps full-dup after
switching to long-distance mode;
(3) User can configure POE long-distance working mode in Menu- Camera- POE configuration,
the default status is OFF;

 

[MakoMillenium]

I use Tenda 5 port desktop POE switch 803.2af/at input is 51 volts DC and 58 watts total or 30 watts per port (4 ports) supplies up to 250 meters just flick a switch to select full duplex for shorter range higher speed or half duplex for long range lower speed. Uses all eight cores for power delivery. Also appears to have some lightning protection. Tenda TEF1105P 5-port 10/100Mbps unmanaged switch-Tenda-All For Better NetWorking

 

[Bryan]

PoE is rated to 300ft, along with ethernet.. it does this by injecting a higher voltage (48vdc) then the camera regulates it down to 12v and applies it to the 12v rail.. just like they transmit power to your house at a higher voltage.

as long as you use 23-24awg cat5e/cat6 it'll be fine if you stay within specs; if you wish to go further you use a PoE extender to get a lil more distance or use 24vac

And don't use 32 AWG flat cable as you warned me...that was really helpful...kept me from ordering 16 rolls.