Buried splice?
 

I have a 12-3 w/g wire (120v) running from a subpanel on the end of my house out to where we formerly had an above-ground pool. The line is run thru buried conduit to the end where it comes up to a receptacle box that sticks up about 15" above ground. I would like to extend that wire on out to provide service to another structure in the backyard, but would also like to do away with the receptacle box sticking up in the middle of the yard. Is there a safe and legal way to bury the splice?

If this is UF cable, there are listed splice kits that can be buried.

If this is conduit with individual conductors you will need to extend the conduit and pull new conductors. A hand hole box would work also, but would need to be flush with the soil.

I'm not a high voltage expert, but I gather that you'll need a pull box in the ground at the splice point and that you'll need the box/hole to be deep enough that you can support the splice case up off the ground so that when water gets inside, it doesn't interfere with the splice. I'm absolutely certain that there are electric codes on this though, and they should definitely be consulted.

I would also imagine that there are sealed splice cases available that can be direct-buried, but I would expect that those require a professional to be brought in.

It is UF, and I think I'll try the splice kit approach -- thanks!

If it is not UF then the wrong cable was used and it should be replaced.

Even though it is in conduit it is required to be UF? I didn't know that.

Yes, the inside of conduit is not a location, so if the conduit is installed outdoors, it is still considered in a wet location.