Baby proof 240V outlet(for air conditioning) in living room
I think that what you want is an In-Use Cover.



Secondly, baby fencing is a must. If you don't have some, or don't need it here, you'll need it somewhere. If you don't want to attach it to the wall (understandable), just set something heavy (like a box or bucket of stuff) on the inside and oustide of the fence to support it and keep baby from knocking it over.



EDIT- Mounting an in use box:



EDIT- Plate kit: