Pipe fill calculation

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Danny89

Member
Location
Indian Land
Happy weekend fellas!

Want to make sure I got this right.

Situation...
3 inch emt 16 inches long from feeder distribution panel to troth.

Therefore no need for 310.15(b)(3)(a)
Reference chapter 9 table 1 note (4)

Now calculate 60% fill thhn wire for 3inch emt.

Chapter 9 table 4. Emt 3 in:

60% fill = mm2 (3421) , in2 (5.307)


Chapter 9 table 5. Thhn 12awg:

Mm2 (8.581), in2 (0.0133)


So...

3421÷8.581= 398.67...

398 wires 12 awg thhn can legally fit in 3 in emt that is 16 inch long because it is filled just below 60%.

I think that's right...

Thanks in advance!

Sent from my Moto Z (2) using Tapatalk
 
Fulthrotl

Fulthrotl

~Autocorrect is My Worst Enema.~
Location
HB, CA (19 Hrs. 22 Min. from Winged Horses)
Occupation
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Danny89 said:
Want to make sure I got this right.

Situation...
3 inch emt 16 inches long from feeder distribution panel to troth.

Therefore no need for 310.15(b)(3)(a)
Reference chapter 9 table 1 note (4)

Now calculate 60% fill thhn wire for 3inch emt.

Chapter 9 table 4. Emt 3 in:

60% fill = mm2 (3421) , in2 (5.307)


Chapter 9 table 5. Thhn 12awg:

Mm2 (8.581), in2 (0.0133)


So...

3421÷8.581= 398.67...

398 wires 12 awg thhn can legally fit in 3 in emt that is 16 inch long because it is filled just below 60%.

I think that's right...

Thanks in advance!
Click to expand...

40% fill is 266#12's.
actually, you can use 399 #12's legally.

hope that extra wire helps you out.

i have a bag of pretzels and a soda here...
can i come watch while you lace this up?
:cool:
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Doesn't seem likely this is a real life scenario but if it is, be careful when you get to your "troth" because 310.15(B)(5) does apply once you exceed 30 cc conductors in any cross section.
 
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