The USW-Flex (UniFi Flex) switch can be used outdoors or indoors and has some flexible options for powering it up. It has five gigabit ports with 802.3at (PoE+) output on ports 2-5 with PoE in supported on port 1.

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About PoE on the USW-Flex

Port 1 supports input at 802.3af, 802.3at, 802.3bt and passive PoE at 50v - 57V using a separate PoE injector. Ubiquiti recommends using the POE-50-60W which can be found online.

This PoE injector setting also applies when using the USW-Flex-Utility outdoor enclosure, with its included power supply.

However, when we change how the USW-Flex is powered the switch has to be configured in order to ensure proper operation.

⚠️ Note: Failure to set the correct method can result in PoE powered devices rebooting randomly, as the device struggles to keep them powered.

When the USW-Flex is powered by PoE, the following PoE budgets are applied:

• 802.3af – PoE Budget: 8W
• 802.3at – PoE Budget: 20W
• 802.3bt – PoE Budget: 46W
• PoE Injector ( U-PoE++ ) – PoE Budget: 46W

Changing the PoE input

To change the input method for the USW-Flex can be done in two ways, using the New GUI and the Legacy GUI in UniFi.

New GUI

From the 'New GUI' click on the 'Devices' section

Click on the USW Flex in the devices list

Once the device side panel has appeared, click on the 'Settings' tab

Next, click on the 'Services' drop down

This will reveal the 'Power Source' settings. There are three options, 'Use device settings', '802.3af' and 'PoE Injector'.

Select the one most appropriate for your use case.

⚠️ Note, this section will not be here if the switch is powered up via 802.3at or 802.3bt. In this situation, you don't need to set anything.

Legacy GUI

From the 'New GUI' click on the 'Devices' section

Click on the USW Flex in the devices list

Once the device side panel has appeared, click on the 'Settings' tab

Next, under the 'Power Source' settings. There are three options, 'Use device settings', '802.3af' and 'PoE Injector'.

Select the one most appropriate for your use case.

⚠️ Note, this section will not be here if the switch is powered up via 802.3at or 802.3bt. In this situation, you don't need to set anything.

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