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#172030 - 12/11/07 05:57 AM 8/3wg romex
sparkync Offline
Member

Registered: 10/17/02
Posts: 811
Loc: NC
According to the wire table 310-16 ( 99 Code Book, I don't have my new book with me) # 8 wire is good for 50 amps in the 75 degree column, and I know this is good only if the terminals are rated 75 degrees, which they are. Does
8/3 with ground romex qualify for this rating also? I had an inspector tell me once that it didn't, but I can't find where he would have got that from unless it was in an old code at the time. Thanks, Steve...

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#172031 - 12/11/07 06:30 AM Re: 8/3wg romex [Re: sparkync]
earlydean Offline
Member

Registered: 12/22/03
Posts: 749
Loc: Griswold, CT, USA
He is maybe refering to 334.80, which limits the ampacity of NM cables to that of the 60 degree column.
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#172034 - 12/11/07 08:37 AM Re: 8/3wg romex [Re: earlydean]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
Yup that is what he is talking about and you can't get away with the "round up" trick you can with #6 since 40 is a standard breaker size. Even if you decide to go for SE/SER you still can't use the 75c column because of 338.10(B)(4)
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#172072 - 12/11/07 07:45 PM Re: 8/3wg romex [Re: gfretwell]
KJay Offline
Member

Registered: 11/27/07
Posts: 763
Loc: MA, USA
Hi Greg,
I could be wrong, but I thought 338.10(B)4 excluded 334.80 Ampacity.

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#172079 - 12/11/07 09:36 PM Re: 8/3wg romex [Re: KJay]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
You are right. I should try to read a little better before I speak. My original thought was that it was OK, then I looked it up. ;\)
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