Ok, I was up for this challenge of, is it legal to run one mombo Pvc connector to run a whole panels branch circuit system through, which I've seen and to me is lazy as , well you know ...
If I was an Inspector I'd say .. check 334.30 ... right were is says within every support within 12" of enclosure such as outlet boxes cabinet or ( fittings ) the key word is then fittings or should I say approved fittings, a pvc fitting does not maintain the clamp or crimp that a NMB connector possesses, So the argument would then be, what is an approved soft sheathed connector, does it need to be lightly compressed to prevent slippage. Anyone care to contribute to the question of using a pvc fitting or even just a large chase nipple. Besides I'm sure there's a violation just by having 3" of cables crammed together like that.
check 334.30 (A) other than they refer to horizontal I'm sure the NEC board would consider this as an applicable situation, as noted : and the non metallic sheathed cable is securely fastened in place by an approved means of each .. .. cabinet .. ( or other non metallic cable termination )
PVC connectors are not non metallic cable termination fittings.