I request service drops in every circumstance where I'll (or my climbing line or tree limbs) be within 10 feet. I had a 35 foot redbud to prune last fall and it was over a service line. I called in the utility and he used his 40 ft. bucket to prune part of it for me so that he wouldn't have to drop the line. I knew he would do that, and still called because I don't f*ck with power lines unless I'm an ISA certified (or other similar cert) line clearance arborist. Power line shock is a leading cause of mortality in our industry. My superficial understanding is that
@rico is right, if the cover is intact you'll be fine. If it's not and you contact it with water or metal (yourself, wet climbing line, branch, silky hayachi, foggy day, etc.), you'll get zapped with enough juice to stop your heart, but not fry you outright.