#2 NM Cable

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Jimmy7

Senior Member
Location
Boston, MA
Occupation
Electrician
Can you use #2 NM cable on a 100 Amp breaker? I believe NM cable can be used only at 60 degrees, so if that's the case, #2 copper is good for 95 amps. Can't you utilize the next size up rule and use a 100 Amp breaker?
 
Jimmy7 said:
Can you use #2 NM cable on a 100 Amp breaker? I believe NM cable can be used only at 60 degrees, so if that's the case, #2 copper is good for 95 amps. Can't you utilize the next size up rule and use a 100 Amp breaker?
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I have used #2 copper NM cable several times to feed sub panels and used a 100 amp circuit breaker on jobs that had permits & passed inspection. Used #6 NM cable that were feed by 60 amp circuit breakers. Was taught that you can use the next higher breaker ampere. Done 800 amp services and used 500 MCM copper THWN in parallel that were at the time rated for around 380 amps or 760 amps total on a 800 amp circuit breaker. Came back to one 800 amp service that had 500MCM copper wire and drawing between 680 & 715 Amps to see if customer could add additional equipment. Performed IR scan & voltage drop readings several times and did not find any problems
 
Use MC. I was talking about it in another thread. It’s cheaper(by me at least) and easier to work with. I used for a 100 amp sub feed. I normally buy sub feeds in mc. For smaller circuits it’s nm for sure
 
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