Subscriber Discussion

Does Max PoE Distance Change With Cable Used?

UD
Undisclosed Distributor #1
Jul 28, 2016

Hi,

I am looking for a table that gives me the maximum distance I can do over CAT5, 6 and 6E with different PoE classes. Or better, a usable calculator?

Thanks in advance!

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Brian Karas
Jul 28, 2016
IPVM

If you're talking about standards-based PoE, and not proprietary "power on unused pairs", it's 100M, same as Ethernet distance limitations.

UD
Undisclosed Distributor #1
Jul 28, 2016

No I am talking about standards like IEEE802.3af or at.

I can imagine that the PD requires a certain voltage level to function so there comes the voltage drop in the cables. But that is just technical interest.

So can rely on the standards mentioned, that any PoE IEEE802.3at camera will work within 100m when the PoE switch also supports this PoE class? (Using CAT6 cabling)

U
Undisclosed #2
Jul 28, 2016
IPVMU Certified

Yes.

BS
Bob Schenck
Jul 30, 2016
IPVMU Certified

To explain further, since you have a technical interest:

The POE standard accounts for resistance of the cable and maximum cable length. The 802.3af standard calls out a max power draw at the powered device(PD) of 12.95W and requires the power sourcing equipment(PSE) to supply at least 15.4W. The 802.3at standard increases the power to 25.5W available for the PD and 30W required from the PSE. So both standards include a loss budget for the wiring between the PD and PSE.

Anything Cat5 or better will not exceed the power loss budget, even at 100m length. You can even go as low as Category 3 cabling at 100m for 802.3af POE, but the newer 802.3at standard dropped Cat3 support.

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Brian Rhodes
Jul 28, 2016
IPVMU Certified

You are limited to 100m regardless of Cat or PoE class per IEEE 802.3 af/at specs.

(1)
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Gert Molkens
Jul 29, 2016
IPVMU Certified

If you stick to the standards (100 m channel length), any CurrentnPoE type will woek as they are specified to be used on thses standards (Cat.5e, 6, 6A, ....)

for the power side of things voltage drop,on the cable might be the main concern regarding length but don't forget there's an ethernet side of things as well. As for ethernet, there are a lot more things to take into account than the voltage drop/ resistance of the cable that limit the length to 100m for a channel

U
Undisclosed #2
Jul 29, 2016
IPVMU Certified

It's never too late to enter the Ethernet Challenge !

UI
Undisclosed Integrator #3
Jul 30, 2016

Going 670 feet on a CAT6 was not the plan, but apparently it worked with a camera plugged in directly to an embedded Hikvision NVR. This is my only run over 300 feet with all of my client base.


The accepted spec is 300 feet as people stated above.

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