Annex C1 error

[Rick S.]

While teaching my class how to use Annex C when using conductors of all the same size, I asked them how many #8 THW conductors could I install in a
1" EMT. They answered 8 and I agreed. But when we double checked the answer in Tables 4 and 5, we came up with a surprise.
Table 4 shows an allowable fill at 40% as .346 Table 5 shows a #8 THW to have a dimension of 0.0437
When calculated, it comes up to be .3496 which exceeds the 40% column in Table 4. In all my years of double-checking Annex C, this is the first time that I have found it to be inaccurate. would someone please double-check my findings?

 

[jumper]

What edition/year are you using?

Previous editions had errors but I thought they were fixed.

 

[Dennis Alwon]

What edition/year are you using?

Previous editions had errors but I thought they were fixed.

I get 8 both ways

.346/.0437 = 7.9--- now look at Note 7 last sentence

 

[Dennis Alwon]

You had me worried as I spent many hours formulating that table. I thought maybe there was an error somewhere in the table.

Back before the 2014 Nec there was an error with the labeling of the conductor insulation. I believe it was on the first page of each section where they switched the Rhw... and thw... column

 

[Rick S]

Thank you for clearing that up.

 

[Dennis Alwon]

You're welcome