As I read 300.11, we are not allowed to use the ceiling grid to support out pipe and boxes.
As this pic shows, some firm went to great lengths to manufacture assorted connectors for this specific purpose.
I look at B-Line's catalog shows they make a variety of such connectors (such as model BA-14).
So I ask some questions:
---Is it possible that B-Line would manufacture, even list, items that we're not allowed to use?
----Do I mis-understand the NEC? If I'm to apply the NEC, just how do I ascertain the "ceiling system menufacturers' instructions?"