re: Running electricity to my shed

best way to do it is unhook the old line since you want it gone, and this way you can just cut off below ground where it sticks up and just bury it.

next, from where it was connected to house power, you dig a trench to the shed about 8-12" deep and use a 12/2 romex wire safe for underground use and slide it inside 3/4" pvc pipe and run it to the shed. use 10/2 if there might be a chance you want to run more then just a light and single outlet in the shed one day.

it is code approved to use pvc pipe as underground electrical conduit so use it from the point of electricity taken from house to the shed. you want the pipe to avoid the accidental nick from a shovel one day when you or the kids dig a hole.

there is no real "need" to even glue the pipe or fittings but tap them on so they are fully tight. its a bit fiddly getting the wire in the 90 fittings but its not hard.