Re: Closest I've had to that ....
> the cable run was clearly marked on the plans
unmarked cables can be fun, too. a colleague of mine was in his former life (late 80s, early 90s) a civil engineer and his crew cut a totally unexpected cable in the building pit.
some minutes later the whole area was flooded by patrol cars (both German police and US MP ones) - they "found" a secret NATO communication line.