CalculationsQuestion 26 of 110
Six current-carrying THHN conductors share one raceway. If the 90 C ampacity of #6 Cu is 75 A, what is the adjusted ampacity after the fill adjustment factor for 4-6 conductors?
a.75 A
b.60 A
c.55 A
d.52.5 A
Explanation
For 4 to 6 current-carrying conductors, apply an 80% adjustment factor: 75 A x 0.80 = 60 A.
Law Reference: 2023 NEC Table 310.15(C)(1)Practice all 110 questions free — no signup required.
Related questions on this topic
- A 208-V three-phase feeder carries 40 A over 150 ft using #6 Cu (CM = 26,240, K = 12.9). What is the approximate voltage drop?
- For a 112.5-kVA, 208-V, three-phase transformer with 2% impedance, what is the approximate available fault current at the secondary terminals (infinite primary)?
- A 45-kVA, 208-V, three-phase transformer has 2% impedance. What is the approximate available fault current at its secondary (infinite primary)?
- A #3 Cu THHN conductor has a 90 C ampacity of 110 A. In a 50 C ambient (correction factor 0.82), what is the corrected ampacity?
- A #2 Cu THHN (90 C ampacity 130 A) runs with 6 current-carrying conductors (0.80 factor) in a 40 C ambient (0.91 factor). What is the adjusted-and-corrected ampacity?
- An office has 45 general-use receptacle outlets. At 180 VA per outlet, what is the receptacle load before demand factors?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against Master Electrician Licensing Exam (NEC-based) · How we review