The way I understand de-rating of conductors per NEC 310.15(B)(3)(c) is that it applies only to de-rating conductors on a roof that are in circular raceways and conductors in other raceways such a gutters or in cables like armor interlock or outside rated mc cable are not covered by this section. Is this correct?
NEC 310.15(B)(3)(c)
- Thread starter wyboy
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chris kennedy
Senior Member
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- Miami Fla.
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- 60 yr old tool twisting electrician
Thats how I read it, "circular raceway" was a change from the 08 so crafty contractors couldn't say it doesn't apply to EMT. You bring up a good point that could lead to future change.
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