I just installed a 3x3 ct can (one on each side of a cinder block wall) with nipples going through the the wall.
This was done in order to avoid crossing pipes. Instead i just cross the wires inside the junction box.
But, my question has to do with the responsibility of box calculations. They seem quit complex in this situation.
I've got three 3" nipples going through the back of the box. On one side a 3 1/2 and a 2 1/2 and on the other side two 2 1/2 inches. On top of this, the forman wants to add 3 more 4" nipples going out the back for some more pipes and future use.
Would you take it upon yourself to go through all the angular calculations. And inquire about wires sizes in order to use table 312.6A.
I could see the jw being resposible for the diagonal dimension between k/o's (6xpipe size) since you have control over that. But when you are given a box , do you just assume it is sized within code, or not?
