Sometimes the CMP will not have control over the final language that is presented in the actual text of the NEC. I do not know if this is the case with this wording.
I do not know if we can get a response from the manufacturers, but it cannot hurt to try. I will email a couple and see if they respond to the use of the 'holes' in the side of a metallic box.
For one, I would never pass the use of screws or nails supporting a plastic box mounted from the inside of the box, except for the new (listed) Smart Box.
I have used the holes in the back of 1900 or 4/11 box, but not the side - that is what a bracket box is for. I have mounted the others on walls and ceilings many times.
Maybe the holes we see on the side and towards the front of the 1900's is for mounting 'ears' so the box can be mounted in an existing wall???? Did you notice that they are smaller than the holes in the back of the box?
Bob
You asked if the holes have to be tested for listing, I am not sure of the actual wording for the listing/testing standard, but I would think so - just my opinion.
Pierre
