Hi guys I am confused as to how to calculate for conduit fill and calculate for derating. Does 310.15 work hand in hand with the fill chart or are they 2 totally different calculations? I am wondering if oversizing an EMT pipe run would have any barring on the derating calculation? Or do we derate 4-6 current carrying conductors to 80% even if they are running in a 3” EMT pipe?
Using table 310.15 and conduit fill chart
- Thread starter Dansos
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jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
Still gotta derate. Two different issues. You could run a 12” conduit and still have to derate four #14 CCCs.
kwired
Electron manager
- Location
- NE Nebraska
Different issues, but today where you typically are using 90C conductors @ 75 termination ratings -you usually don't have to increase conductor size until you get past 9 CCC's and get into the 50% or lower adjustment factors, unless ambient temp correction is also needed.
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