Sizing pvc for wire pull

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crtemp

crtemp

Senior Member
Location
Wa state
I am going to be pulling seven 12 gauge THHN wires (six current carrying and a ground) and am trying to figure out what size schedule 80 conduit would be required. It looks like I am ok using 3/4 pvc to do this. I come up with the wires having a size of .0931 in sq and the 3/4 conduit having a total fill of .164 in sq. Am I ok to do this or do I have to adjust for heat?
It's going to be a 240 volt wall heater circuit, and 120 volt bath receptacle circuit, a 120 volt sump pump circuit and a 120 volt lighting circuit. The bath and sump pump circuit will share a neutral.
Thanks for any advice.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
crtemp said:
I am going to be pulling seven 12 gauge THHN wires (six current carrying and a ground) and am trying to figure out what size schedule 80 conduit would be required. It looks like I am ok using 3/4 pvc to do this. I come up with the wires having a size of .0931 in sq and the 3/4 conduit having a total fill of .164 in sq. Am I ok to do this or do I have to adjust for heat?
It's going to be a 240 volt wall heater circuit, and 120 volt bath receptacle circuit, a 120 volt sump pump circuit and a 120 volt lighting circuit. The bath and sump pump circuit will share a neutral.
Thanks for any advice.
Click to expand...
Derating (adjustment for heat) affects wire ampacity. Conduit fill is solely a function of wire size. So you are good with 3/4" unless your pull tension warrants a larger size.
 
crtemp

crtemp

Senior Member
Location
Wa state
Smart $ said:
Derating (adjustment for heat) affects wire ampacity. Conduit fill is solely a function of wire size. So you are good with 3/4" unless your pull tension warrants a larger size.
Click to expand...

Ok thank you for the response. I will only have two 90's and one LB so I should be ok.
Thanks again.
 
Little Bill

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
For future reference, if you're pulling the same size/type wires, you can use Annex C in the back of the code book.

Example in your case: you can have up to 12 of THHN 12AWG in Sch 80 3/4" conduit.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
crtemp said:
The LB is just a pull point going into the crawl space. Is this a problem?
Click to expand...
Pull point is fine. Pull through is not.

See smiley after comment? It was meant more as a tongue-in-cheek comment, since you stated "so I should be ok" rather than asking.
 
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