I have a small network in our 2nd location, with few UBNT PoE devices. Until last week all devices were powered on by old Toughswitch 5P, I guess they are called Edgeswitch 5xp now.
I have 4 devices, Nanostation M5, Unifi AP, I think first model, with green LED, and 2 older UVC cameras. All devices are connected with UBNT Toughcable and plugs, and that thing alone is a major pain to deal with. Anyway, all devices worked fine on 5xp switch.
Last week we added 24 port PoE switch, US‑24‑500W model. Of the 4 above devices only AP would power on, but connection wouldn't remain stable, it would turn on and off every few minutes. We also measured voltage on shield of the cable, it was leaking 50 VDC and 115 VAC. No voltage while it was connected to 5xp switch. Further troubleshooting and I ended up making non-shielded extension cable, with keystone jack on one and, and all devices would power on from Unifi switch.
Last few days we added small rack with shielded pass-through patch panel, and connected everything through it. We had to add ethernet couplers and extra cable because original cable runs were too short, both couplers and cable are shielded. Cables from patch panel to switch were unshielded. In that setup, again only AP would power on. I had to replace cables running from couplers to patch panel with unshielded ones, to get the devices to power on.
I have couple of PoE phones and they power on just fine. The difference is these are PoE+, and Ubnt devices are passive 24V.
Does anyone have any idea what could be the issue here? Ubnt support didn't get me far, they asked for logs from the switch, but I'm sure problem is electrical and won't show up in logs. One difference is that ports on 5xp switch are isolated, while on patch panel and Unifi switch it's metal touching metal. Btw, sparks were flying occasionally when plugging in Ubnt devices into new switch, I guess wires from 2 cables were touching.
Pics of setup (sorry, no cable porn, will tidy up when it's finished):
Switch, PoE+ ports to the left, Passive 24V to the right
Patch panel
Couplers with unshielded cables