How does the freezing of water cause flashes of frost?

Feed to the outbuilding

Close, but not a banana

You are near a correct build here, but there is a problem: your stated cable installation depth is for PVC under normal conditions too low . Code requires the top of the conduit to be 18 "underground if you are walking through a courtyard, so you will have to dig up to 20" deep.

Also, I would use a 1 "or 1.5" pipe here to make it easier to pull, and schedule 80 instead of 40, as the former is more resilient to mechanical damage than the latter. You'll also need a pair of pre-made wide-angle bends to bring the barrel and expansion fittings up at the junctions to accommodate earth movements.

As for the wires - 8AWG THWN is a suitable wire size (here a little more than absolutely required, but okay) and you must four Laying wires in the line: two hots, a neutral conductor and a ground conductor - the ground is of vital importance here as it is a completely different and complementary Functions as the floor bar in the outbuilding. (That is, the ground wire returns erratic utility power the original way, while the ground rod serves to return surges naturally (also known as lightning) to solid terrain.)

Why 240V? That way you can distribute the loads on the two legs of the feeder, reduce the voltage drop and provide 240V for the next guy who owns the space.

The part about laying the entire cable duct and that subsequent Pulling the cable through is important to avoid damaging the cable insulation and avoiding excessive sheathing. You can use a shop to suck up a foam "mouse" (or even a plastic bag in a pinch) tied on a piece of string through the conduit to serve as a pull cord, and then tie the string to the wire and use it it to pull it off again.

MI Brian

"Unauthorized overvoltages" - AKA lightning? Entertain my new questions: Why the two hots? Do I need the 30A in the Home Load Center or can I establish a direct connection to the panel? (Or two hots each on a 30A?). I get the wide sweeping and expansion fittings - MI freeze and thaw. Is it mandatory to allow the "pull" provided when installing Conduit Over Run while I bury it. Is 3/4 "allowed with line fill equation? Thank you for your time 3PhaseEel

Three-phase eel

@MIBrian - yes, also known as lightning related stuff. The two hots allow you to supply 240 VAC to the control center, which is more efficient than 120V. Yes, you need a 2-pole 30 A circuit breaker in the house control center. It is absolutely necessary pulling the wire through the conduit (pulling it over the conduit will damage the wire insulation too much) and 3/4 "is allowed. However, if you go to 1" you are less likely to have to beg An electrician will help you rescue your train.

Limo driver

I thought you had to be below the frost line to prevent burials? You need 2 hots to give 240 screws so you can run 240 things in the future ... kiln, compressor, heaters etc

Three-phase eel

@LimoDRIVER - The extension fittings are picking up any movement due to flare-ups etc. Burying below the frost line is only relevant for water pipes to prevent water from freezing in them.

Limo driver

Thank you, ThreePhaseEel. I'm in South Florida, don't worry about freezing down here.