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#52670 - 06/02/05 01:04 AM #6/2 NM Good for 65 amps?
aldav53 Offline
Member
Registered: 08/22/01
Posts: 545
Loc: Chandler, AZ USA
The code book says #6 THHN is good for 65 amps. Is 6/2 NM considered THHN? Its not marked that. How many amps is 6/2 NM good for? At Home Depot they have 6/2 labeled rated at 50 amps. ??
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#52671 - 06/02/05 01:28 AM Re: #6/2 NM Good for 65 amps?
plcnewbie Offline
Junior Member
Registered: 05/18/05
Posts: 10
check out 334.80 ampacity NM is 60 degree rated conductor

[This message has been edited by plcnewbie (edited 06-02-2005).]
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#52672 - 06/02/05 02:22 AM Re: #6/2 NM Good for 65 amps?
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
Because of 334.80 6/2 NM is rated 55 amps.

With the use of 240.4(B) many times you can use a 60 amp breaker with 6/2 NM.
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#52673 - 06/02/05 09:56 PM Re: #6/2 NM Good for 65 amps?
aldav53 Offline
Member
Registered: 08/22/01
Posts: 545
Loc: Chandler, AZ USA
Couldn't find the code art. 6/2 NM is supposed to be 90 deg rated, which is the same as THHN, which would be 65 amps.
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#52674 - 06/02/05 10:56 PM Re: #6/2 NM Good for 65 amps?
gfretwell Online   content


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Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
334.80 Ampacity.
The ampacity of Types NM, NMC, and NMS cable shall be determined in accordance with 310.15. The ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The 90°C (194°F) rating shall be permitted to be used for ampacity derating purposes, provided the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.
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