Calculating raceway fill. Rounding up or down

[little george]

1-1/4 in EMT #1 THHN Table C4 allows 4 conductors. This exceeds the 40% fill limit per Table 1 Why is this allowed?

 

[infinity]

1-1/4 in EMT #1 THHN Table C4 allows 4 conductors. This exceeds the 40% fill limit per Table 1 Why is this allowed?

Table C1 says 4 THHN in a 1.25" EMT. Table C4 for Intermediate Metal Conduit also says 4 conductors.

 

[augie47]

The "secret" is in Note 7 to the Tables (Pg 679) which allows you to go tp the next number of conductors when your math gives you a fill of 0.8 or more (you can round up)
Doing the math if you divide the available area for a 1-1/4 ( .589) by the area of the #1s you get 3.828 which allows you to round up to 4
The Tables in Annex C take this into account

 

[Dennis Alwon]

1-1/4 in EMT #1 THHN Table C4 allows 4 conductors. This exceeds the 40% fill limit per Table 1 Why is this allowed?

Table C1 is for EMT

The reason it is allowed because of Note 7

Gus got it ...