Conductor Fill Class 1 Div 1 & 2 Seals

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killer76

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I could use some help to determine the conductor fill in a conduit seal ,

Article 501.15(C)(6)

my application has 24 # 12 THHN and 6 # 10 THHN

in table 5 I see approximate diameter and approximate area

do I use the diameter or area

I see the cross-sectional area must not exceed 25% the conduit

#12THHN =.130 x 24 conductors = 3.12
and
#10THHN =.164 x 6 conductors = .984

total 4.104


the next question do I use nominal or total area
a 3" conduit
if nominal is 3.085 and 25% is .7725


it must be area 7.457 and 25% is 1.86875


this is were need help


I have done this before I just can't remember the correct method



thanks
 
think I got it

area of wire #12 THHN is .0133 x 24 = .3192
#10 THHN is .0211 x 6 = .1266

=.4458

2" Rigid nominal diameter is 2.083 25% is .52075


so a 2" will have spare


someone please confirm, maybe I should have posted this in calculations area

thanks again
 
Use Chapter 9 Table 4 for the area of a raceway. Use Table 5 for the area of the conductors. The #12s are 0.0133 square inches each and the #10s are 0.0211. The total area of all of the conductors is 0.4458 square inches. If that is to repesent a 25% fill, then multiply by 4 for the minimum required area. That is 1.782 square inches and the smallest trade size of rigid conduit would be 1.5" with a total area of 2.071. It looks like you were working with the diameter of the conduit and not the area.
Don
 
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