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#6/2 NM Good for 65 amps? #52670 06/02/05 04:04 AM
Joined: Aug 2001
Posts: 545
A
aldav53 Offline OP
Member
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. ??


The Golden Rule - "The man with the gold makes the rule"
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Re: #6/2 NM Good for 65 amps? #52671 06/02/05 04:28 AM
Joined: May 2005
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plcnewbie Offline
Junior Member
check out 334.80 ampacity NM is 60 degree rated conductor

[This message has been edited by plcnewbie (edited 06-02-2005).]

Re: #6/2 NM Good for 65 amps? #52672 06/02/05 05:22 AM
Joined: Jan 2003
Posts: 4,391
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iwire Offline
Moderator
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.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: #6/2 NM Good for 65 amps? #52673 06/03/05 12:56 AM
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Posts: 545
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aldav53 Offline OP
Member
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.


The Golden Rule - "The man with the gold makes the rule"
Re: #6/2 NM Good for 65 amps? #52674 06/03/05 01:56 AM
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gfretwell Offline
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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.


Greg Fretwell

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