I've seen lead sheathed cable in both electrical wire and phone wire. The company that I retired from had miles of lead sheathed underground electrical cable, mostly in the underground network systems in the older parts of downtown in larger metropolitan areas. If you are walking on a sidewalk and cross a steel grate there is probably a transformer or a piece of switch gear down there! Thankfully I never worked on that stuff! Also, a lot of overhead telephone cable was sheathed in lead back in the day. I still know where there is a lot of it. Not being a telephone man I don't know if they buried lead cable or not. Its mostly soft lead, running around 98% pure.