Table 310.15(C)(1) Adjustment Factors For More Than Three Current Carrying Conductors

[VSAT LLC]

In the 2020 code book. In Annex C conductor fill Table C.1 page 731 the number of THHN 12 awg conductors allowed in a 1 1/4 EMT = 45.

Table 310.15(C)(1) states that if you have (21-30) 12 awg THHN current carrying conductors in a raceway those conductors have to be adjusted by a factor 45%.

My question is do I need to perform an ampacity adjustment of 45% if I put 25 THHN 12 awg current carrying conductors in a 1 1/4 EMT that allows a conductor fill of 45 THHN 12 awg conductors?

If the answer is yes because they are in a raceway. Then the raceway size does not matter. If I installed the same 25 THHN 12 AWG conductors in a 4 inch EMT raceway that allows a conductor fill 443 conductors they would still require a 45% ampacity adjustment. Are my thoughts correct?

Thank you for your responses.

 

[david luchini]

So my question, is do I need to perform an ampacity adjustment of 45% if I put 25 THHN 12 awg current carrying conductors in a 1 1/4 EMT that allows conductor fill for 45 THHN 12 awg conductors?

Yes, the size of the raceway has no bearing on the adjustment factor.