OleSparky
New member
- Location
- City of Parkland
I need clarification between 2011 NEC 334.80 and 334.112.
NEC 334.80 says to rate conductors at 60* C and 334.112 says 90* so long as the NM type cable is identified with a -B. Am I reading that right? This has come up several times when wiring 10K heat strips for instance with #6 NMC romex. At 60*C it's only rated at 55Amp. If the nameplate is one the AC AHU is 58A they would need to run pipe with #6 THHN or use a #4 romex? Or if it has the -B (NM-B) you can use the #6 romex because the 90* column gives you 75A rating instead of 55A in the 60* column.?
NEC 334.80 says to rate conductors at 60* C and 334.112 says 90* so long as the NM type cable is identified with a -B. Am I reading that right? This has come up several times when wiring 10K heat strips for instance with #6 NMC romex. At 60*C it's only rated at 55Amp. If the nameplate is one the AC AHU is 58A they would need to run pipe with #6 THHN or use a #4 romex? Or if it has the -B (NM-B) you can use the #6 romex because the 90* column gives you 75A rating instead of 55A in the 60* column.?