Conductor fill

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4wirenuts

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Warrenton, VA
Hey so I have a wire calculation issue. The contractor has 3” schedule 40 PVC with a fill rating at 40% is 2.907. The wire is #10 PV wire rated at 2000 volts with an outside diameter of .264. I think you have to solve for Cross sectional area of the PV wire which would be Pi times the radius squared. Then divide that number into the 2.907.... I come up with 26 conductors however the contractor is claiming he is allowed 50 conductors.
 
4wirenuts said:
Hey so I have a wire calculation issue. The contractor has 3” schedule 40 PVC with a fill rating at 40% is 2.907. The wire is #10 PV wire rated at 2000 volts with an outside diameter of .264. I think you have to solve for Cross sectional area of the PV wire which would be Pi times the radius squared. Then divide that number into the 2.907.... I come up with 26 conductors however the contractor is claiming he is allowed 50 conductors.
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I think you've made an error somewhere. I come up with 53 conductors with on OD of 0.264" fitting in a 3" sched 40 PVC.
 
Your methodology is correct. Cross sectional area of the raceway @ 40% when over 2 wires divided by the cross sectional area of wire being installed.
But your doing something wrong with your math. I use the numbers you've provided and get 53 conductors.

There are different types of Shc. 40 PVC and the result could potentially be higher, but not lower.
 
4wirenuts said:
Hey so I have a wire calculation issue. The contractor has 3” schedule 40 PVC with a fill rating at 40% is 2.907. The wire is #10 PV wire rated at 2000 volts with an outside diameter of .264. I think you have to solve for Cross sectional area of the PV wire which would be Pi times the radius squared. Then divide that number into the 2.907.... I come up with 26 conductors however the contractor is claiming he is allowed 50 conductors.
Click to expand...

You divided the OD of the conductor by the square root of 2, instead of by 2, to get the radius.
 
david luchini said:
You divided the OD of the conductor by the square root of 2, instead of by 2, to get the radius.
Click to expand...
Nicely done. I was trying to replicate the same result and couldn't get it. How you thought of this as the error I will never know, lol.

I was trying the radius without squaring, without pi, the diameter squared, the diameter without squaring and without pi... everything I could think of. This would have never occurred to me. Bravo sir.
 
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