Discrepancy in Annex C

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melissa.seals

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Centered around the 2005, I'm referring to #10 THW conductors fitting in 2 1/2" EMT. If you use Table 4 and 5, doing the calculation, it states that you can fit 96 conductors. If you flip to Annex C, in some of the publications, it states that you can fit 70 conductors, yet in some of the publications of like year that my student's own, it states the same answer as if you do the calculations in Table's 4 and 5!! My instructors and I have verified that in comparison to the 2002 and 2008 code books, they also state that you can fit 70 conductors in the 2 1/2" EMT!!! The only discrepancy, is the lack of THW-2 for #10 and #12 AWG in all the code books that reference 70 conductors for the pipe fill question!!

Do you have any insight on why this happened, if you have encountered this issue? This is highly irritating when you're trying to teach a student the correct information, then you encounter something like this.

Thanks for your time in reading and replying to this.
 
iwire

iwire

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melissa.seals said:
This is highly irritating when you're trying to teach a student the correct information, then you encounter something like this. .
Click to expand...

It is a great teaching tool, you teach them to do the calculations and ignore the Annex. :)

The Annex is not part of the code and if your students blindly follow it they could run into trouble.
 
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melissa.seals

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I do not introduce Annex C to my students at all, neither do my other instructors, but we found this by using a sample Experior Journeyman test and 96 was not listed as a possible answer, hence this question.
 
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Volta

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The annex also allows three 300 kcmil XHHW regular or three 350 kcmil XHHW compact conductors in a PVC schedule 40 conduit. It shouldn't.
 
roger

roger

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Volta said:
The annex also allows three 300 kcmil XHHW regular or three 350 kcmil XHHW compact conductors in a PVC schedule 40 conduit. It shouldn't.
Click to expand...

What size conduit and why not?

Roger
 
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melissa.seals

Member
WOW, now you're going to have me looking for all kinds of mistakes now!! Haha. This stands for more reason on why we don't introduce Annex C. Ought to just tear the section out of the code book!!
 
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