So the only place I could find this was on Amazon, with this description (bold emphasis mine)
This item YuanLey Gigabit PoE Injector 30W, PoE+ Injector Converts Non-PoE to PoE+, Power Over Ethernet Injector 48V IEEE 802.3at/af, 10/100/1000Mbps PoE Adapter Plug & Play, Distances Up to 325 Feet
WHile both POE_ and 802.3at are 30W, 802.3at is 54V, POE+ (pre-standard, mostly Cisco) is 48V, so this is NOT an 802.3at injector, this is a 48V POE+. This will not work on APs that require 802.3at at 54V to operate (like the AP-27x and all outdoor APs after that require 802.3at). So send this back and whatever you buy, make sure it's 54V 802.3at, NOT 48V :)
Additionally, it's worth noting that POE injectors are PASSIVE (a little known fact), so even if your switch is only 802.3af 15W, if the injector senses ANY POE power on the non-powered line, it will pass on whatever PoE it detects on to the powered port, and will not 'inject' it's own power (whatever it supports).
But I'm pretty sure the AP is not detecting the voltage it would expect 51V+ after the cabling drop, and is likely seeing 47 or less which the AP will not operate on.
Let us know if you find a true 54V AT injector and if it works!
Sent: May 23, 2023 03:49 PM
Subject: IAP-277 won't run off poe+ injector
I have 2 IAP-315s running 22.214.171.124_79369 off a Juniper EX2300C switch. I bought an IAP-277 to add an outdoor AP to the cluster. Because of the way I had to route the wiring it made more sense to connect the 277 to my SRX320 (non-poe) so I purchased a Yuanley HG30A POE+ AT midspan injector. I ran the initial configuration with the 277 connected to the EX switch and everything went fine with all radios operating. When I moved the 277 to the poe injector and SRX the AP connects but the radios shut off. I thought it was because the SRX was causing an issue but the port is set as to ethernet switching and if I replace the poe injector with another EX2300 connected to the SRX it works. So AP277 > EX2300C(1st floor)> SRX320 > EX2300C(2nd floor) > AP315s.
I wanted to rule out the multiple switches and srx so I connected the AP277 to the same switch as the other APs with poe shut off and the poe injector in between and I'm still not getting it to turn on the radios. AP277 > POE+/AT Injector > Switch (POE disabled) > AP315s no joy. If I enable POE and plug the AP277 directly everything works.
I'm stumped. Anyone have any suggestions? I'm believe the POE injector is bad/faulty but I can't figure out how to determine how much power its delivering to the AP. The switch shows the AP only draws 8.2 W:
# run show poe interface ge-0/0/9
PoE interface status:
PoE interface : ge-0/0/9
Administrative status : Enabled
Operational status : ON
Power limit on the interface : 30.0W
Priority : Low
Power consumed : 8.2W
Class of power device : 4
PoE Mode : 802.3at
If anyone knows of an injector that works with the 277 I'd appreciate the recommendation.