I am currently looking to wire a 12' X 20' metal shed detached from the house. The panel box is approximately 120' from the shed. I will have no major tools running at any one time. I plan on running wire above ground from the panel under the double wide then go underground the rest of the way. Majority of the run is above ground then plan on using direct buried romex the rest of the way. Since there won't be many tools used and possible two light fixtures, I plan on using a 15amp breaker.The plan is to have 5 outlets and then a light switch to operate on outlet after the 5 outlets. My question is is this the way to go and will I need a ground rod? And what size romex? Any help would be appreciated. Thanks guys!

The entire run can be UF cable, (direct buried NM Cable, looks like Romex). Be sure the cable is Type UF.

I suggest the minimum size, due to distance, be #10 copper.

This can be on a 20 Amp GFI breaker at the panel, and if the cable is GFI protected, the underground portion can be 12 inches deep.

For a separate structure fed by one circuit, a ground rod is not required, however, being a metal shed, it would be wise to have one for lightnining protection

The circuit feeding the structure needs to have the bare equipment grounding conductor connected to the metal frame, and if you chose to use a ground rod, connect the shed to the rod with a #6 bare copper conductor.

There does need to be one switch at the shed to act as a disconnect for the circuit.