Romex for HVAC

[scnkapc]

Can you run 8/2 romex to a Air Handler in residential.
334.80 says romex is rated at 60*, but 334.112 says the insulation is rated 90*.
Confused!

 

[Scratchbuilt]

If its NM cable, then 60* ampacity is required regardless if the conductor inside is rated for 90* per 334.80. the 90* rating is only to be used for ampacity adjustments. Lets say you are feeding a 50A rated range receptacle, then you would need to install # 6 instead of # 8. I have this discussion all the time with electricians. Even though # 8 is rated at 50A from the 75* column, It's only rated 40A at 60*.

 

[Scratchbuilt]

I forgot to ask, what is the MCA and MOCD for the unit?