The Meraki MR34, MR42, MR52, and MR53 access points require 802.3at power to provide full PoE functionality. Some switches and PoE injectors are not capable of supplying this level of power. If the MR is receiving less power than the 802.3at standard, it will display "running in low power mode".
MR access points use LLDP to negotiate power level. Make sure the switch or other connected device is configured to negotiate power level with LLDP.
Our documentation covers this configuration with Cisco switches.
While in low power mode, the MR will disable its Air Marshal radio as well as one out of three transmit streams on the 2.4 GHz band (leaving two transmit streams still operating). Despite being in low power mode, the device can still supply full 802.11ac capabilities.
If the device is running in low power mode, ensure that the power source supports the 802.3at power standard and that it is supplying full power to the device. To identify if the AP is running in low power mode, navigate to the AP on dashboard.meraki.com. Once there, under Status there will be a field that indicates the Power source and if the AP is in low power mode. Please see below.