I have a sub-panel in my garage and there is UF cable 12-2 running underground to my shed with a disconnect box, and the 12-2 wire is running to a GFI. Within the shed, I have another 20 amp outlet, two ceiling lights on a single pole switch and two outside lights on their own switch. I’m adding a gazebo on my deck and need to add a ceiling fan with a single pole switch and one outlet. Can I run another UF 12-2 underground to my shed and tie the wires to the disconnect box or to the other 20 amp outlet?
Here is the diagram: