5 ton air conditioner for commercial

[la2151]

HI.. Am I correct in reading art 440 that i can use #8 Thwn/Thhn for a 43 amp minum / max 50 amp circuit? tThe panel is a square D QO. Breaker is rated at 75 degrees. This is a commercial roof top unit. A friend says that rule is for resi only? Thanks for the advice & help.

 

[LarryFine]

The allowance is for all HVAC equipment so marked.

 

[Dennis Alwon]

#8 thhn if installed in a raceway with no other derating involved is rated for 50 amps anyway. No issue. There is a lot of false beliefs that commercial code is different than residential. There are some differences but overall the code is the same.

The fact is if this were nm cable in a residence it would not be allowed with #8