conduit fill table

[sabar]

When using the table for conductors allowed in conduit, is allowance arlready made for more than 3 current carrying conductors so you don't have to derate ?

 

[texie]

When using the table for conductors allowed in conduit, is allowance arlready made for more than 3 current carrying conductors so you don't have to derate ?

Absolutely not. Conduit fill is a physical thing and has nothing to do with derating.

 

[augie47]

agree,, two totally different animals... conduit fill is exactly what it states..number of conductors in the conduit... the ampacity of those conductors may vary for many reasons including number of conductors, ambient temperature, etc.

 

[infinity]

Maximum fill is calculated to keep the conductors from being damaged while being installed. Derating is calculated to keep them from exceeding their insulation temperature value and causing insulation failure.

 

[joebell]

This is probably wrong but I was taught that the tables are based on 40% fill and one reason for this is to aid in the dissipation of heat produced by the installed conductors. I do agree that the table does not account for any ampacity adjustments or corrections.

 

[ActionDave]

This is probably wrong but I was taught that the tables are based on 40% fill and one reason for this is to aid in the dissipation of heat produced by the installed conductors. I do agree that the table does not account for any ampacity adjustments or corrections.

No. 40% fill all about how much room there is for the wires in the conduit.

I don't know if you have ever looked at the pictures in the handbook; seems there is a whole lot more room on paper than there is in real life when you are the one stuffing all those wires in the pipe.