This power adapter can be used to plug an ecobee EB-STAT-02 or EB-EMS-02 thermostat into a standard 120 volt outlet, if 24 volt power is not available from the furnace or air handler.  This plug supplies power directly to the equipment interface module installed near the furnace or air handler.

Most ecobee thermostat installations use 24 volt power from the furnace or air handler. This plug is an optional accessory only required when that is not possible.