Under the NEC, article 310-15(B)(2)(a)- Adjustment Factors. More than three current-carrying conductors in a raceway or cable exceeds three, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(A).
I am looking for an interpetation for the Neutral Conductor as described under 310.15(B)(4)(a) - A neutral conductor that carries only the unbalanced current from other conductors of the same circuit shall not be required to be counted when applying the provisions of 310.15(B)(2)(a).
Here is the situation, the contractor ignored the electrical plans that called for no more than 3 branch circuits per homerun and ran a total of 6 branch circuits with 6 phase conductors and anywhere from (2) to (4) neutral conductors as well as equipment grounding conductors. In most cases, the branch circuits were rated 20 amps, 120 volt. Also, the contractor did not de-rate the conductors and ran # 12 wire. One of the conduits was a 1-1/2" and had 7 phase conductors, 6 neutral conductors and 4 equipment grounding conductors.
If the neutral is considered a current carrying conductor, the contractor will have to replace the #12 wire with # 8 wire since Table 310.15(B)(2)(a) states that 10 to 20 current-carrying conductors must be adjusted by 50%.
Any opinions as far as if the neutral conductors should be considered current carrying conductors?