conductor volume

[jimport]

Can someone please tell me what I am not seeing? 1.25 EMT has an area of 1.496. For over 2 conductors the volume is 40%. 1.496 x .4= .598

Table 9 says 4 #1 THHN are allowed in 1.25". #1 has an area of .1562. .1562 x 4 = .6248 which is over the 40%. I also need to add a #6 with a volume of .0507. I get a total volume needed of larger than .6755.

Thanks,

 

[LarryFine]

According to this calculator, even a bare #6 takes you up to 1-1/2".

Raceway Fill Calculator

 

[wwhitney]

Can someone please tell me what I am not seeing? 1.25 EMT has an area of 1.496. For over 2 conductors the volume is 40%. 1.496 x .4= .598

Table 9 says 4 #1 THHN are allowed in 1.25". #1 has an area of .1562. .1562 x 4 = .6248 which is over the 40%.

.598 / .1562 = 3.83, and Chapter 9 Note 7 says that you can round up 0.8 or higher. So the Table lists 4 conductors. Definitely can't add anything else to those (4) #1 THHN.

Cheers, Wayne

 

[jimport]

I had not remembered the .8 method. I was just going on the straight math answer.

 

[steve66]

Can someone please tell me what I am not seeing? 1.25 EMT has an area of 1.496. For over 2 conductors the volume is 40%. 1.496 x .4= .598

Table 9 says 4 #1 THHN are allowed in 1.25". #1 has an area of .1562. .1562 x 4 = .6248 which is over the 40%. I also need to add a #6 with a volume of .0507. I get a total volume needed of larger than .6755.

Thanks,

Yes, you seem to have a valid point. (4) #1 THHN should not fit in a 1.25" conduit, but Table C.1 says it does for both THHN and XHHW.

My Square D Slide Ruler also seems to be taken from Table C.1, because it also says (4) #1's fit in a 1.25" conduit.