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Conduit size ?

grego

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Apr 25, 2009
Messages
251
Location
Sac, CA
It's getting late and I have been working around the clock but I must be going cross eyed.
I am planning to run 4x#2 copper wire to my garage and I am planning to use 1 1/2" pvc schedule 40.
Here's were the confusion starts, according to the NEC 2008 book table c.10 for the maximum number of conductors in a 1 1/2" pvc using thwn#2 wire is 5

When I use the calculator for the cross section - 4 x 9.754mm = 39.016mm & the nominal internal diameter for 1 1/2" pvc is 40.4mm, how is there room for the 5th conductor?

So I guess my question after searching ALL the pages of this section and finding nothing solid then taking the gaint leap of trying to understand the NEC book, is, will 4 #2 copper wire fit in the conduit?
The builders used a 1 1/2" sweep in the foundation and I will have to chip it out if I have to use 2", a huge pain in the behind and not something I want to do.
Time to go to bed.:bounce:
 
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tfi racing

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Apr 19, 2008
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Cedar,BC
Four individual #2 conductors?Around these parts the ground and neutral can be considerably smaller than the hots,better have a better look at your local code.
 

ArthurPE

Banned
Joined
Jun 14, 2009
Messages
423
you need the area, not the diameter

in round numbers:
cable 4 x Pi(10/2)^2 ~ 315 mm^2
conduit 1 x Pi(40/2)^2 ~ 1256 mm^2

% fill ~ 315/1256 ~ 25% < 30% you're good to go

you should use a full size neutral, and the ground can be reduced based on the upstream CB
 
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grego

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Apr 25, 2009
Messages
251
Location
Sac, CA
I plan to run all the same size as I got a deal on 400 feet of #2 wire. I can use a reduced sized ground if I need to depending on if all the wires don't fit in the conduit but it sounds like I can so no problem.
 

tfi racing

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Apr 19, 2008
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Location
Cedar,BC
If that's the case,I would use what you have then,but use a smaller ground because I don't like to work so hard!
 

Charles (in GA)

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Jan 11, 2006
Messages
12,489
Location
50 mi south of Atlanta
Table C.10 list seven as the number of conductors of #2 THWN in a 1-1/2 rigid PVC sch 40.

Chapter 9, table 4 says a 1-1/2 rigid PVC sch 40 has a max fill of .794 inches squared for over two wires (40% fill max) (total internal area is 1.986 in square)

Table 5 says that THWN #2 has an aprox area of 0.1158 inches square (each wire)

.4632 in square is the aprox area of four #2 THWN wires

Charles
 
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