PoE over STP or UTP? Cat 5, 5e, 6 or 6a?

RouterOS General
1

I am perfectly happy with current MT products: use them at work and at home. Now moving in another house and refitting the place - the question is, what cable to use for mild PoE (and PoE+ in the future)? 1Gbps is a must, looking into the future 10Gbps is desirable.

This is not the MT related question, but a year ago somewhere in THIS forum I saw a topic where non-shielded cable is a must for PoE, but I see similar topics in the other forums where usage of shielded cable is also “OK”.

UTP, or STP? Cat 5e, 6, 6a? Clarify me, please, as some Routerboard will be a backbone of the network :slight_smile:

Thank you.

2

I think you may have read a post relating to some specific unit limitations (Dynadish) when used in passive poe mode (not af/at).

I’d use regular Cat5e or Cat6 STP cable, in any case the aspect I would be more zealous about is getting perfect ducting, so that you are able to upgrade any cable easily.

3

The cables would be non-removable - they will be buried in concrete. I will use it for couple of IP cameras, 1 AP, some other light devices, probably all PoE standard.
Should I choose shielded Cat 6 or not?

4

Don’t use cat cable then. Use fiber which is extremely cheap these days at about $1 per foot. Get the 50/125 OM3 850nm Aqua jacket type. What is nice about fiber is when running between buildings. You don’t need all the surge protection.

Otherwise use 2in electrical PVC pipe. Then you can add or remove as needed.

5

Using shielded cable cannot do any harm certainly, and AFAIK no indoor equipment has the same limitations as the dynadish.

Considering you cannot replace the cables, and you want to be ready for 10Gbe, your safest investment would be 6a.

6

Just to clarify:

There’s no single “POE standard”; right now POE can be “Active” (af/at) which in addition to sending power by the wires, requires the device to be powered to have specific active circuitry to support it.

This is what most SOHO PoE switches provide, to power most VoIP phones, IP Cameras, which are usually also af/at.

“Passive POE”, refers to just sending the power by the wires, no active circuitry involved. This is what Mikrotik and most WISP segment POE switches provide, targeted to APs, Routers, some IP cameras, etc.

Just noticed wAP, supports both Passive POE, and in addition, Active POE (af/at), with the requirement of using unshielded cable.

I guess this “unshielded” refers to the requirement of not using “armored” or shielded RJ-45s in contact with the cable shield (used to protect from environment interferences) or drain wire (this is used for outdoor installations in order to discharge ESD) so maybe by using non-armored RJ-45s with the shielded cables will do; will research about this approach.

In any case, even if this wasn’t possible, you are going to deal with Active and Passive POE devices, so the more flexible approach is having both an Active (af/at) switch to power your af/at devices (IP Cameras, VoIP phones, other devices) and in addition a Passive POE switch (or POE Injector Patch pannel, like http://www.i4wifi.eu/EU-230V-powering-1/Gigabit-12-port-pasiv-POE-injector-panel-shielded.html) at your network rack, so that you can power both kind of devices and maintain a tidy and neat rack closet.

Active-Passive POE converters are very rare, and usually not worth the cost; also defeat the purpose of neatness at the rack.

Mikrotik devices supporting af/at (a handful models AFAIK) also support passive POE with no shielded cable restrictions, so you can just use Passive POE with all Mikrotik devices.

7

What??
Cables should never be “buried in concrete”… always use tubing.

8

Certainly, proper ducting is the best investment you could make, much more than any kind of cable; it will save you headaches in the future (what if you want to lay fiber or anything else in the future, or a cable is damaged while laying down concrete?).

Even with ducting you’ll need to be after the ones laying it down, because 9 times out of 10 they’ll screw it, either by making holes, knots, breaking it, leaving too tight curves, et al.

Imagine what they can do with a (rather fragile) cat 6a cable being buried in concrete.

9

You could lay TERA E12 and terminate with RJ45 adapter cords.

10

As I told before - it is not possible. I know that it is not a good practice, but the silicate brick walls have to be scraped out for cable, so scraping out for larger diameter tubing is not possible (read: expensive).

11

for cabling the most future proof you can go is with CAT 6A FTP with that you can go up to with 10gigabit ethernet.

maybe cable with 22awg conductors caliber you ensure the best possible PoE performance to the future, also if possible design to reduce the length of every cable

taking in count the cable will be buried in concrete maybe a good idea is to use some kind thin plastic sleeving something like a hose to protect the cable from concrete over the time and to protect it from people of the construction labor, if that’s not possible get outdoor cable and hope the best

keep in mind cable is not designed to be buried in concrete, will be not a surprise if after a few years cable cease to work for some reason

cat6A FTP awg22 outdoor, maybe to specific and hard to find in the market, using a hose to protect cable can remove the outdoor requirement for the cable making easier to find it in the market

i think the best will be
cat6A FTP AWG22 and a hose to protect the cable

12

I don’t think so. If Cat 7A TERA feels too exotic to you, you can always lay Cat 7A GG45.

13

This is a large amount of the info you provided, thank you very much! I have only theoretical knowledge of PoE.

My network will have no harsh environment: everything inside the apartment, only the thing that cables will be not in tubing. But the problem is I am confused ATM: my network will consist of MT and other manufacturers devices, the flexibility is probably very high on this list, from what I am reading on internet ability to use “Active” (af/at and bt in future if possible) standard devices in network are priority, shielded cables will make NO harm, right? Suitability order:
-Cat 6A F/UTP (or any combination of pair/cable shielding?)
-Cat 6A UTP
-Cat 6 F/UTP (or any combination of pair/cable shielding?) - probably I will need that 10Gbit link not so soon, and it will be closer than cable limit lenght
-Cat 6 UTP
…
-Cat 5e UTP

Right?

14

I wouldn’t take mikrotik af/at POE shielded suitability as criteria to select the cables, as I said few indoor APs support it, and those who do, additionaly support passive POE no matter if the cable is shielded or not, so you will always have the option to power them by using a POE injector, Passive PoE switch, or Passive POE pannel from the network closet.

So yes, that would be the order.

As forum mates pointed, I wouldn’t bury the cables in concrete if it were my house, isn’t there any other possibility? How are you going to carry your electrical installation? Won’t you have ceilings suitable to pass ducts with cables?

15

everything is ok with the ceilings, they are suspended, but the end points (sockets) have to be on the wals, which are solid silicate brick, in such case I have to scoop not a ~1-1.5cm, but much much larger diameter. If that is not possible or too expensive I will stick with burying them in concrete… If done right - I do not see that as a big problem.

16

I recommend you Cat 6A F/UTP, because is recommended for the better performance for 10g ethernet without the expense of Cat 7 o cat 7A, and without much trouble with cabling practices impact on cable performance

PoE performance is related to voltage drop over cable and current capacity

Be sure of using full copper cable, some brands are using alloy to lower costs, using full copper that will improve PoE performance

For PoE or any kind of power transmission over cable the AWG caliber of copper conductors has a direct impact on voltage drop and current capacity of cable, because that is recommended AWG 22 caliber of copper conductor on the cable to improve its electrical characteristics.

UTP cable of 22awg caliber can be rated for up to 100watt of power over the 4 pairs, at 0.6 amperes of max current using 48volt PoE

http://blog.fosketts.net/toolbox/power-ethernet-calculator/

17

25GbE equipment s expected to cost the same as 10GbE.

Maybe TERA E12, which is rated at 1200MHz, might be enough in the end.

So it’s not necessarily throwing money, when in addition the connector gives you more application flexibility.

A bit of bad timing, before Cat.8 is finalized.

18

i suggest not to buy anything is not published as a confirmed and proved standard, most the time is marketing smoke

it happened with cat 7 and cat 7A, some time ago was a selling argument it will be supporting speeds over 10g ethernet but now we know that is not true because 25g ethernet is in the process to define what will be the specs of cabling needed until now anything is write or confirmed, ther are talking about cat8 but anything confirmed or tested

it happened with cat6A for 10 gigabit ethernet many buildings was wired in the last decade with cat6a cabling not able of 10g ethernet because today we know cat6a without shielding only perform well if the cabling practices are perfect and with some restrictions far from real world installations, today we know cat6A F/UTP is capable of 10g baseT in real world conditions.

dont buy expensive marketing smoke, buy real proven and available technology

19

I think it depends on how much more it costs, if it’s not easy to recable later, if we are talking about individual wire shielding.