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#96350 - 11/20/05 12:02 PM 366.7
ngoody24 Offline
Member

Registered: 09/25/05
Posts: 34
Loc: pace,FL, United States
Hi guys i have a question for yall.
366.7(a) says when you have 30 or less current carring conductors the correction factors specified in 310.15(b)(2)(a) shall not apply.
(b)however a nonmetallic auxiliary gutter the derating factors specified in 310.15(b)(2)(a) shall be applicable.

Is this because one is plastic and one is metal. one has a chance to melt and one doesnt? any help would be great. thanks

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2014 / 2011 NEC & Related Books and Study Guides
#96351 - 11/20/05 01:07 PM Re: 366.7
earlydean Offline
Member

Registered: 12/22/03
Posts: 749
Loc: Griswold, CT, USA
A quote from Mark Ode of NFPA in Electrical Contractor Magazine from 2000: "The metal wireway dissipates heat better than the nonmetallic wireway, which is likely to be affected by excessive heat from the conductors."

I guess your assumption about maybe melting the plastic gutter was correct.
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Earl

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