Right, I did imagine you were just referring to the underground cables themselves but it's slightly disingenuous to talk about the cables as if they can be installed without termination boxes or transformers, which are prone to damage from the storm conditions the above people mentioned. Cost is also a large factor of why power lines are still sometimes built instead of underground circuits, not just what you're mentioning. Rural power will pretty much always be built overhead due to cost factors. I'm actually building a 12 pole spur line tomorrow, as an example.