Ran into something to that end some odd 20 years ago on the grounds of a condominium association. Had to hire five guys to dig a very very wide and deep hole to China it seemed. Power lines crossing gas lines and fire mains ,what a mess.It seemed to me the code book was thrown away when those units were built.
The plumbing outfit backed out of the dig because of liabilitiy's.
Originally it was thought the problem was just a leaking fire main,but mysteriousely the outdoor lighting was disrupted and some other electrical issues too ! The condo association people thought I might be able to track down the electrical issues, little did they or know or did I know it was going to become a massive digging operation with shovels !
But somebody's got to do it !
Needless to say a backhoe was out of the question and the blue prints were not at all accurate about the locations of those power lines in relation to those gas lines or those water lines underground.The plumbing outfit guy handed me the prints and pointed to x marks the spot to start to the best guess he or they had ! Good luck he said and have several fire extingushers handy just in case !
Don't know that a underground electrical patch would be the fix- if so that would cost less than restringing the line.Underground electrical patchs are code rated and if the damage is confined to a specific area -say root bound ,than it;s a matter of pin pointing that particular point in the line.
perhaps a long shot ,but it may offer a glimmer of hope in realtion to cost of repair.
I Imagine that will depend upon what it all looks like when the line is exposed.
Best of luck with that.
Roots,rocks and earth quakes.