Shock, maybe one of the guys who knows the code better than I will correct me, but there has never been a code requirement for limiting paralleled conductors to 2. As long as you follow the ampacities in 310.16 and allow for derating as per 310.15(B)(2)(a) you can parallel as many conductors as you want. Heck you can even do them in groups of 3.

310.4 is the basic code for paralleling

392.8(D) gives the only place that limits the number of conductors. and this is only if you have A,B,C and a Neutral in the same conduit.

but then again, I tend to hide the code book more than look at it, so [Linked Image]