The main problem you have here is the cable size(csa) as that will dictate the fuse you can have protecting the circuit. Which will limit the load you can have plugged in to it.
If you do consider using this circuit for the fridge, it would be safer to either
install 5amp socket outlet
View media item 44801
and 5amp plug to appliance.
View media item 44802
or connect the flex of the appliance to the existing FCU with 3A fuse in then there would be no chance of an appliance of a higher rating being connected.