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derating rooftop conductors #214531 12/18/14 11:28 PM
Joined: Mar 2004
Posts: 765
B
BigB Offline OP
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When derating THWN-2 copper conductors for ambient that will eventually terminate in a sub panel with a 125 amp rating can I use the 90C column?

2017 / 2014 NEC & Related Books and Study Guides
Re: derating rooftop conductors [Re: BigB] #214533 12/19/14 04:54 AM
Joined: Jun 2004
Posts: 1,273
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Tesla Offline
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The sole and only reason for that column IS derating.

For there are no 90 degree rated devices out there.

One then uses the lesser computed ampacity limit.

So, yes, you start with the 90 degree column.


Tesla

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