Bob
You are correct in saying that CMP members do use specific language. But remember that some of the requirements go back to the past before some of the methods today have been encountered or thought of.
I was at the Eastern section meeting this past month and there were several CMP members present. It is informative not only to hear the code issues, but to talk to them and hear how hard the process can actually be.
This very subject of how the support of boxes was brought up, and they used some slides and open conversation to discuss this.
Boxes, especially plastic boxes are not designed or "tested" (the key here is 'tested') to be supported by the wall of the box from the inside of the box. Because of the non tested part and the fact that manufacturers will not say it is to be installed in that fashion, it is a violation.
They also brought up another interesting aspect of the nails or screws installed through the box within 1/4 inch from the back - that if a screw is used, the threads pose a hazard to the conductor insulation, and require a sleeve over the shank of the screw threads that pass through the box. So much for using screws through the box.
Pierre
