PoE issues with Unifi switch
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@marcinozga said in POoE issues with Unifi switch:
@wrx7m said in POoE issues with Unifi switch:
@marcinozga said in POoE issues with Unifi switch:
@wrx7m said in POoE issues with Unifi switch:
I don't deal much with shielded. They look kinda messy. Isn't the shielding supposed to be in the connector with the rest of the cable?
That cable is really messy. Normally you would get just aluminium foil, but these have wire on top, like coax, then plastic foil and ESD drain wire. The worst cable I had to work with. The connectors are also shielded. Everything in this setup was shielded, and ground was at patch panel. I had to break the shield between couplers and panel to get PoE to work.
Seems like a pain, for sure.
Literally, I was pulling wires from my fingers for a while after working with that.
Ugh. That is terrible. Little metal splinters suck.
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I wonder if you have a ground loop happening when you used shielded the whole way, but switching to unshielded broke the loop?
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Shielding should be connected in both ends on networks cables. This is not an audio cable and shielding works differently for high frequency than for low frequency. A 1 gigabit connection sees 250Mhz while audio sees about 10000 times lower frequency.
Also you'll get the best shielding when you have both foil and a braid together in the same cable.
You will not get ground loops on networks because there are isolation transformers in every ethernet port.
Passive PoE is not a standard. Use switches that follows the standard and you likely wont have any problems. These are the standards: https://en.wikipedia.org/wiki/Power_over_Ethernet
BTW, rack should be grounded if it isn't.
PS. Picture below is a network card based on Intel i350. The two black things next to each ethernet port are the isolation transformers.
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Anyway, find the actual problem by disconnecting everything and connect things one by one.
Real PoE for instance negotiate power the the device on the other end. I think PoE supports a crossover ethernet cable just like any switch or NIC can. But passive PoE? It'll probably short-circuit something.
If a cable is crossed somewhere like TIA-A or B wiring in the wrong place you might have a situation like that.
PS. You might want to get a cat6 cable tester so you can verify the wiring. A simple one would get the job done.
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@Pete-S said in PoE issues with Unifi switch:
Passive PoE is not a standard. Use switches that follows the standard and you likely wont have any problems. These are the standards: https://en.wikipedia.org/wiki/Power_over_Ethernet
Not an option, Ubnt devices work only with Passive PoE.
BTW, rack should be grounded if it isn't.
It is. Shielding is connected on both ends, but grounded only at patch panel, and that's grounded to rack.
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@Pete-S said in PoE issues with Unifi switch:
Anyway, find the actual problem by disconnecting everything and connect things one by one.
I've done that, the result is as described in op, only AP powers on, and leaks voltage somewhere.
Real PoE for instance negotiate power the the device on the other end. I think PoE supports a crossover ethernet cable just like any switch or NIC can. But passive PoE? It'll probably short-circuit something.
No crossover cables in use, in fact I haven't seen crossover cable since 1 Gbit became standard, even in direct connections.
If a cable is crossed somewhere like TIA-A or B wiring in the wrong place you might have a situation like that.
No cross anywhere, cables have been tested and mapped, during installation few years ago and again last week.
PS. You might want to get a cat6 cable tester so you can verify the wiring. A simple one would get the job done.
I have one, from Fluke Networks.
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@marcinozga said in PoE issues with Unifi switch:
Passive PoE is not a standard. Use switches that follows the standard and you likely wont have any problems. These are the standards: https://en.wikipedia.org/wiki/Power_over_Ethernet
Not an option, Ubnt devices work only with Passive PoE.
Sounds like you've checked all the obvious things. However the above statement confuses me.
The new switch you have installed, US‑24‑500W, is a real PoE switch. How does it know that it should send out power to the ports where you have installed "passive PoE" devices?
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@Pete-S said in PoE issues with Unifi switch:
@marcinozga said in PoE issues with Unifi switch:
Passive PoE is not a standard. Use switches that follows the standard and you likely wont have any problems. These are the standards: https://en.wikipedia.org/wiki/Power_over_Ethernet
Not an option, Ubnt devices work only with Passive PoE.
Sound like you checked all the obvious things. However the above statement confuses me.
The new switch you have installed, US‑24‑500W, is a real PoE switch. How does it know that it should send out power to the ports where you have installed "passive PoE" devices?
Each port can be set to either PoE+, Passive 24V or no PoE at all.
12 ports to the left are set as PoE+, 12 to the right are Passive 24V.
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PoE+ port:
Passive 24V port:
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@marcinozga
Have you measured if there is any power on those ports?From what I could find from UBNT materials:
24VDC Passive PoE (Pins 4, 5+; 7, 8-) -
@Pete-S said in PoE issues with Unifi switch:
@marcinozga
Have you measured if there is any power on those ports?From what I could find from UBNT materials:
24VDC Passive PoE (Pins 4, 5+; 7, 8-)I'm guessing there is, since installing a non shielded cablelet in the run solves his problem. another reason I asked about a ground loop. I don't understand the science behind the ground loop - I was way to tired to read it when posted earlier - so no clue if it could still be a culprit or not.
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@Pete-S said in PoE issues with Unifi switch:
@marcinozga
Have you measured if there is any power on those ports?From what I could find from UBNT materials:
24VDC Passive PoE (Pins 4, 5+; 7, 8-)I didn't, but I don't have to, all devices are powering on just fine with unshielded cables. The most bizarre thing is that cables from switch to patch panel are unshielded already, it's cable between panel and couplers. And I don't think I mentioned it before, but initially there was a shelf on the wall and all cables were plugged in directly into switch, with same end result. I'm strongly leaning to the fact that shield on all cables are connected with unifi switch or patch panel, and that's the root cause of the problem. Otherwise why would everything have worked on 5xp switch (isolated ports) or when cables going to patch panel are unshielded.
