I would not be the least bit surprised if future revisions of the NEC require OCP on the neutral as well as the ungrounded conductors.
I would be very surprised.
As it is now the NEC does not even require a 'super neutral'.
Another thing to consider is that due to European requirements harmonics from the typical PFC equipment is dropping.
In my opinion this is how it should be.
We should not have to 'overwire' a building just because the manufacturers of these power supplies are to cheap to take care of it on their end.
We get many jobs with 200% neutral specs, with the price of copper this seems excessive for a CYA type design.
In branch circuits in particular it seem odd to that when the engineer designs 2 to 4 amps of load on each branch of a 20 amp multi wire branch circuit they feel the need for a 200% neutral.
The 12 AWG THHN is already rated for 25 amps.
