I have had 2ea helpers lately telling me that there is a new code which forbids running romex in a shower or bath tub wall. I had a builder long ago tell me the same thing. I have never found it in the code book. I asked an electrical instructor and he said that the code doesn't exist. I asked about running romex in a fireplace wall and received the same answer. I said okay, how about putting a panel box in a shared wall with a shower or tub. He said, "authorized". I try to avoid these situations, but have installed romex in all these places. Did I miss that paragraph in the code book?