Understanding POE ++ and cable length

Networking & Firewalls
1

Bit of a newbie question, any help or pointing in the right direction is most appreciated:

Ultimately looking at setting up a basic CCTV system but currently just trying to get my head around basic networking and the various technologies out there?

Using a switch that has POE++ ports e.g. USW-Pro-24-PoE-EU
Are you able to run a 75m CAT6 cable to a POE switch e.g. USW-Flex and then run 4x POE cameras using a 75m - thus creating a total distance from the original source of power 150m?

If so at what distance does the POE/data start to have trouble with CAT6 cable?

2

What is the wattage draw of the switch and 4 cameras? In general I would say this is a bad idea, but it might work if you can pull that much power from the original switch.

The data sheet on the Flex says you can do this at up to 46 watts total which is its limit no matter how you power it, and still max 15 watts per port.

Total PoE Power Budget
Powered by 802.3af 8w
Powered by 802.3at 20w
Powered by 802.3bt 46w
Powered by PoE Adapter 46w
(Enabled in Controller)

3

In theory, assuming 10W cameras (which is realistic) it should be possible?

I guess my question really boils down to the distance of the cabling, 75m either side of the Flex realistic?

FYI - I also note that it is generally a bad idea - however…

4

I would probably want cat6 or better cable for this, and good connectors.

You should check the other switch to see which POE bt type it supports: Power over Ethernet (PoE) Explained: PoE Standards, Types and Power Levels

type 3 may not get the job done, but type 4 should be plenty. The article above does not specify lengths which makes me think that the standard is good up to maximum cable length (100meters?). Bigger conductors almost always equals less loss at distance so if you have control over the cable, use the most stout stuff you can afford, but I would say a good brand and quality cat6 and I’d lean to cat 6a because the cost difference isn’t huge on a per box basis (1000 feet), looks like you need 2 boxes.

5

Look at PoE as from the PoE power source to the PoE device. In you case this is from the PoE switch to PoE cameras. Each camera needs its own cable run back to the switch, they cannot be shared from one run. (yes have seen this IRL)

For each of the cable runs from the PoE switch to the PoE devices, make sure the cable is NOT CCA (copper clad aluminium) because CCA is not good for PoE. CCA cable is almost always cheaper, and if used with PoE you will have problems.

In general the PoE limit is the limit of the cable spec for Ethernet CAT5e/6 which is 328 ft. If you need to run over 328 ft, (100M) add a switch somewhere in the middle and place the PoE switch at the end near the devices that need PoE.

There is a new Ethernet cable product that allows runs greater than 328 ft. (100M) with PoE support called Game Changer cable. Tom did a video on it here at https://www.youtube.com/watch?v=ZY48KUAZKhM

A cable that pulls and terminates like a CAT6 but can deliver 1Gbps and PoE+ over 200 meters - that’s a GameChanger!

6

Thanks for the help - loving blackbox

7

I have seen the video Tom did on the game changer cable - Im based in Europe and the expense of getting hold of it here for my project is likely to be too much.

I have previously ran cat6 cable throughout my house and basically managed a “good enough” job. I didnt really consider the quality of the connector ethernet heads when doing that - how much of a factor in using POE over distance are they and how do I determine quality?

8

thanks for this! would never have realised this without you pointing it out, cheers

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