maximum wire size for 1 1/2' conduit

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Siddiq Kilkenny

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want to run 220 to a pump, 100 ft underground through 1 1/2 PVC conduit. What is the maximum wire size that is safe to put into that size conduit.
 
According to table C.10 it appears you can fit one 800 Kcmil THWN conductor in 1.5" PVC.

I must say your question is backward.

What size wire does the pump require would be a better question.
 
iwire said:
According to table C.10 it appears you can fit one 800 Kcmil THWN conductor in 1.5" PVC.
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This a 220 pump...1 #800 ain't gonna cut it...how about 2 #250's? :D



iwire said:
I must say your question is backward.

What size wire does the pump require would be a better question.
Click to expand...
Yup...work back from the pump ~ what does it require?
30A @220V?
more...less?
 
celtic said:
This a 220 pump...1 #800 ain't gonna cut it...how about 2 #250's? :D
Click to expand...

What was the question?

maximum wire size for 1 1/2' conduit
Click to expand...

I will stick with my one 800. :grin:

But that was kind of the point, as it is PVC it is a safe bet we need 3 wires maybe 4. :cool: '220 volt' does not really tell us.
 
iwire said:
According to table C.10 it appears you can fit one 800 Kcmil THWN conductor in 1.5" PVC.

I must say your question is backward.

What size wire does the pump require would be a better question.
Click to expand...


Bob
1 conductor in a raceway is limited to 53% fill as per Table 1, Chapter 9...
See if your post from Table C1 will work with the table. My math says no, but I am not a mathematical genius. If I am correct, it would seem that the Annex C may have some conflicts with Table 1 of Chapter 9.
 
Pierre,
Chapter 9, Table 4 gives the 53% area of 1.5" PVC (schedule 40) as 1.052 square inches. 800 kcmil THWN is 1.1085 square inches. At first glance, this would say that you can't use the 800kcmil in that size conduit, but Note 7 to Table 1 lets us round up if the fraction is .8 or larger. The available area (1.052) divided by the area of the conductor (1.1085) gives an answer of 0.949 and we are permitted to round up to the whole number of 1 by Note 7.
Don
 
Pump feeder design.

Pump feeder design.

With all die respect, your question shows that you are not qualifies to perform electrical work. I suggest you hire an electrical engineer or a competent electrical contractor.:cool:
 
don_resqcapt19 said:
Pierre,
Chapter 9, Table 4 gives the 53% area of 1.5" PVC (schedule 40) as 1.052 square inches. 800 kcmil THWN is 1.1085 square inches. At first glance, this would say that you can't use the 800kcmil in that size conduit, but Note 7 to Table 1 lets us round up if the fraction is .8 or larger. The available area (1.052) divided by the area of the conductor (1.1085) gives an answer of 0.949 and we are permitted to round up to the whole number of 1 by Note 7.
Don
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Don
Why are you dividing the numbers?

Would you not just take the Size of the conductor and see if it is more than 53% of the raceway size.

PVC - 1.052 inSq

Type THHN -800s - 1.1085 inSq

It would seem to me that the 800s take up more than the permitted 53% inSq of the 1 1/2 PVC.
 
Pierre,
Why are you dividing the numbers?
Click to expand...
Because Note 7 says I can round up if the fractional result is .8 or larger.
(7) When calculating the maximum number of conductors permitted in a conduit or tubing, all of the same size (total cross-sectional area including insulation), the next higher whole number shall be used to determine the maximum number of conductors permitted when the calculation results in a decimal of 0.8 or larger.
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I would expect that is the method used for the Tables in Annex C as well. This removes the possible conflict that you mentioned in post #5.
Don
 
don_resqcapt19 said:
Pierre,

Because Note 7 says I can round up if the fractional result is .8 or larger.

I would expect that is the method used for the Tables in Annex C as well. This removes the possible conflict that you mentioned in post #5.
Don
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Don
Forgive me if I sound like I am arguing, I am not. I am just a little confused by your posts.

I am aware of Note 7. I believe Note 7 is used when actual calculations are performed, not when using the Table C directly. In other words, I perform a calculation to get a number of conductors, then use note 7 after performing that calc... Not using Note 7 for Annex C????
 
Pierre,
I am aware of Note 7. I believe Note 7 is used when actual calculations are performed, not when using the Table C directly. In other words, I perform a calculation to get a number of conductors, then use note 7 after performing that calc... Not using Note 7 for Annex C????
Click to expand...
The numbers in the Tables in Annex C result from the calculations. You were questioning the table that says one 800 kcmil will fit in the 1.5" PVC. The calculations using Note 7 support the table value of one 800kcmil in the raceway. I did not use Note 7 on the results of the table in Annex C, I used the actual calculations based on Table 4, Table 8 and Note 7 to show that the Table in Annex C is correct per the code rules.
Don
 
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