Unifi In-Wall HD powered by a Switch Flex

In my shed, I’ve got a Unifi Flex Utility (a weatherproof enclosure that houses a power supply and Unifi Switch Flex). The Switch Flex powers a UniFi AC Mesh, providing a wireless uplink to the house, and provides wired data to a couple of small devices in the shed. The point of the Flex Utility is that it’s a purpose-built enclosure with sufficient power to run the switch and some other PoE peripherals (cameras, access points etc).

Inside the shed is a bit of a farrady cage, as it’s a steel frame construction, clad in corrugated steel. WiFi signal inside the shed is a bit crap, so I purchased a UniFi In-Wall HD to provide strong signal inside the box.

I liked it because it’s also got a built-in switch, so I can probably position it somewhere near the 3D printers and have direct ethernet connection to them. And it’s sleek and cool-looking and integrates seemlessly into the rest of the ecosystem.

So you can imagine my disappointment when the new In-Wall HD wouldn’t power on properly when I unboxed it and plugged it in. It kept rebooting and watching the console of the switch showed it powering on and then powering off. What was going on?

Turns out, operator error (as per usual). You need to tell the switch that it’s being powered by a sufficiently powerful power supply in order for it to properly power other PoE peripherals (interestingly, it didn’t care about the Mesh AC Pro that was already attached to it.)

In UniFi Controller, Devices -> Your Flex Switch -> Config -> General -> Power Source -> PoE Injector.

To be fair, this is mentioned by UniFi in their product documentation, just in small writing at the bottom of the product datasheet.