jazer
Senior Member
- Location
- Gibsonia, Pa
I have such a hard time with this concept. Ok, from a 3 phase, 4 wire 120/208 volt panelboard, I have a 1 1/2" emt conduit that runs to j-box about 10' away. Inside of this conduit are 5 individual circuits, each designed to be 20 amp, 120 volt receptacle loads. The conductors are THHN #12. 5 blacks (hots) 5 whites (nuetrals) and a single EGC. Now, 310.15(B)(3)(a) and it's sub paragraphs talk about conductors that carry "unbalanced" current from other conductors of the same circuit shall not be required to be counted blah, blah, blah..... So, initially I want to believe that there are only 5 CCC's in the conduit, which would require an 80 percent derating. With THHN, that would still allow overcurrent protection to be 20 amps. However, since this is coming from a 3 phase system, the nuetrals of the first 3 circuits would not count, balancing each other out. How would the remaining 2 be counted? Seems to me that they should count as CCC's, bringing the total up to 7 total CCC's??? Drastically altering the calculation.....or am i overthinking this???
P.S. All other adjustment factors do not apply to this application.
Thanks
P.S. All other adjustment factors do not apply to this application.
Thanks