I have a 12'x16' shed which has been leveled using concrete blocks but otherwise sits on the grass/dirt. It's about 100' from the house. I live in Georgia. I'd love to add some lights and outlets to it.
Can I run an underground electrical wire to it, ending in a 60 amp sub-panel? Or does the shed need to be more permanent with, perhaps, a poured concrete foundation in order to do that?
Yes, the national electric code allows wiring in structures like your shed.
If you plan on using UF wire for the run buried 24” deep you need to bring the wire up in conduit so the wire is protected. If you run conduit, the conduit only has to be buried 18” for PVC. If you run rigid or intermediate metal it can be buried 6”. Burial depths are listed in the NEC 300.5.
With the conduit option, we normally pull thhn as it is dual rated as thwn. (Conduit in ground is considered a wet location.) You would not want to pull UF wire in conduit, and Romex or NMB is not allowed. You might consider aluminum wire at that distance for the feeder depending on what your load is.
Anything more than a 20 amp multiwire branch circuit will require a panel in the shed. There are very small panels that will provide 4-6 circuits but these may be undersized: if you want lights on 1 circuit, outlets a second circuit, possibly a welder or air compressor a double pole circuit... and you are out of room for breakers. So it ends up being better to go with a larger panel (100 amp 20+ circuits). The cost will be close to the same as the smaller panel but you can feed it with 60 or 40; that is fine.
Remember your receptacles in your shed require GFCI protection--even light circuits in the ceiling--if plugs are used. However, lighting circuits that are hard-wired do not require GFCI protection.
With more information, we can help with the wire size or provide additional information.
It is advisable to use a slip joint [expansion coupling] on the conduit stub up, otherwise nothing out of the ordinary. Around here, that's not out of the ordinary even with a poured foundation.
Assuming PVC conduit, 18" cover to the top of the conduit, minimum. Warning tape above. Stub-ups (what sticks out of the ground) need to be schedule 80, and it's advisable to just use schedule 80 for the whole run, as it's a lot tougher than schedule 40. Toss an extra conduit in the trench (trenches are expensive, conduit is cheap) in case you ever want network/phone/intercom/whatever out there.
If you want to spend a lot more on conduit, rigid galvanized steel only needs 6" of cover and serves as the grounding conductor.
A brief word about direct burial cable .vs. conduit: direct burial may look less expensive the first time you do it. It's more prone to fail than wires in conduit are, and it looks rather expensive the second time you do it (trenches are expensive, conduit is cheap.)
