NEC 334 Nonmetallic – sheathed cable (Romax) Type NM / NMC & NMS.
What does the B stand for in NM- B cable?
Aluminum or copper clad aluminum manufactures, are sending this information and it can not be found in the NEC
NM Cable manufactured before 1984 was rated at 60 Deg. C. The NEC required the temperature rating to be increased to 90 Deg. C because of the increased use in dwellings. Wire manufactured after 1984 and rated to 90 Deg. C is labeled NM-B.
Maybe that is true, but the answer lies somewhere in the UL listing. I pulled this off the internet just now:
The types are actually NM-B and NMC-B, where the -B suffix designates that the conductors have 90C insulation.
The difference between NM and NMC seems to be that NMC is additionally rated for moist, damp, and corrosive locations.
From UL 719, Nonmetallic-sheathed cables.
Read the Informational Note to 334.112 for the -B marking and 334.112(B) for NMC
Ah, good to know. I did not know about the IN Note. Then if we read on to 334.116, it gives us the difference about the sheaths. But still no mention of - B.
Thank Y'all, for all your help.
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