derating wire in vertical run

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bgelectric

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I know the answer to this question but im still going to ask it, does wire that only runs vertically need to be derated. For example from a trough down to the panel in emt? because technically its not all bunched up on top of each other.

Also in the code book there is an exception for mc and ac without an outer sheathing about being derated I believe its some where in 310. Can somone expound on this I do not completely understand. thanks
 
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bgelectric

Senior Member
Im glad everyone got a good laugh out of this...

Any input on the second part of the question or is that too serious to reply to.
 
infinity

infinity

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bgelectric said:
Im glad everyone got a good laugh out of this...

Any input on the second part of the question or is that too serious to reply to.
Click to expand...

Is this what you're referencing?

310.15(B)(2)(a)Exception No. 5: Adjustment factors shall not apply to Type AC cable or to Type MC cable without an overall outer jacket under the following conditions:
(1) Each cable has not more than three current-carrying conductors.
(2) The conductors are 12 AWG copper.
(3) Not more than 20 current-carrying conductors are bundled, stacked, or supported on ?bridle rings.?
Click to expand...
 
kwired

kwired

Electron manager
Location
NE Nebraska
the same amount of heat will be given up by the conductors no matter what the orientation is. If vertical the lower section of the raceway is likely to be cooler than the top, but there is still going to be a heat issue someplace in there, so I say yes no need to derate differently just because the raceway is vertical.

In an industrial environment with high ceilings and vertical runs of raceways you may run into additional deration because of high ambient temperature at the upper ends of the raceway(s).
 
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