I think it confused me more.:grin:
Ok the "b" dimension must be 6 times 1 1/4" = 7.5 "
The "a" dimension shows 3 inches in table 312.6(a)
So is that a box 7.5" sq and 3 " deep?
7.5 " is correct but the width can be less so you can have a 4x8 that is 4" deep. More common would be 8x8x4 but it does not need to be any wider than to accommodate the conduit.
You're welcome. I have always had a problem with them also. The graphics, IMO, are a great help.
Exception: Where a raceway or cable entry is in the wall of a box or conduit body opposite a removable cover, the distance from that wall to the cover shall be permitted to comply with the distance required for one wire per terminal in Table 312.6(A).
The distance between raceway entries enclosing the same conductor shall not be less than six times the metric designator (trade size) of the larger raceway.