Annex B table B.310.11???

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nathan

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Until yesturday I did not even know this was there (I hate to admit)I had always used310.15(b)2(a). Do you guys use it much, do you have much luck with it (arguing with inspectors), and is my thinking correct that as long as my loads are diversified (lighting and power in the same raceway) that this table is applicable?? thanks in advance.
 

don_resqcapt19

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Illinois
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retired electrician
Re: Annex B table B.310.11???

In my opinion, you can only use the Annex B tables if the drawings show the use of those tables and the drawings are stamped by a PE.
Don
 

bob

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Location
Alabama
Re: Annex B table B.310.11???

Nathan
I do not see a table 310.11 but 310.5 thru 310.10
are for underground duct bank installations.
Figures 310.2, 310.3 and 310.5 show the typical installations.
 

charlie b

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Lockport, IL
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Re: Annex B table B.310.11???

Originally posted by nathan: ? is my thinking correct that as long as my loads are diversified (lighting and power in the same raceway) that this table is applicable??
I?m afraid not, Nathan. Sorry. That is not the meaning of the term ?load diversity,? as that term is used in Table B.310.11. The meaning is obscure enough, and justifying a specific load diversity percentage is hard enough, that I have to agree with Don. You need a Registered PE to perform (and seal) a calculation, in order to take advantage of the bottom three entries in that Table.

Just to press the point one step further, the following is the definition of ?Load Diversity,? as taken from an old college textbook of mine: ?The ratio of the sum of the individual maximum demands of the various subdivisions of a system to the maximum demand of the whole system." Whatever that might mean, it is not as simple as running power and lighting in the same raceway.
 

nathan

Member
Re: Annex B table B.310.11???

Hey guys thanks for the heads up. It was my foreman that actually brought the table to my attention and some thing just didnt sound right to me, I think Ill just stick to 310.15(B)2(a). Thanks again....if you guys dont mind I have another question if you want to give it a shot its more an NEC question so thats where Im posting it
 
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