Well, I'm not an electrician, or in the position to recite code, BUT, I just had my 100/60/100A service upgraded to 200A underground, in which I buried my phone and cable in the same trench with. I followed the phone/cable/POCO company recommendation of 12" inch spacing from feeders. Cable and phone were run together. Can't say its legit everywhere, but it worked here. What a mess backfilling that trench.
