Alright, a little help here.
Stallcup has, in one of his books, a question about cable bending in "L" "S", and "Z" configurations.

One of my former students now teaches code, and one of his was recently asked a question about cable bending radius based on the above configurations.

I've only been able to give it a few minutes but danged if I can find ANY code reference to it. I will look in Jim's books tonight, but anyone on this forum got a clue?