Just a few questions

[joeyww12000]

Could someone explain to me conduit fill and code that states no more than 3 current carrying conductors in a raceway. On the conduit fill charts you are shown alot more conductors in a conduit than 3. Im sure there is an explanation that makes sense. I would just like to get a better understanding of how to come up with correct amount of circuits in my conduit other than taking someone elses word for it. I know bigger pipe usually means bigger wire not more wires, but I see alot of 3/4 emt upgraded to 1 inch just to be filled up with #12 wire and I know you shouldnt do it. I would appreciate your input.

 

[iwire]

You can put as many conductors in a raceway as the fill charts show.

However as soon as there are more then 3 current carrying conductors in a raceway you have to derate (reduce the rated ampacity) of the conductors.

 

[Dennis Alwon]

Look at T 310.15(B)(2)(a). You can have 20 wires in a conduit-- you just need to derate after 3 CCC

 

[realolman]

You can put more than three in the conduit. You just can't use them to their full capacity. You must derate the ampacity of the current carrying conductors according to table 310.15(B)(2)(a)

Edited... I may not be good, but I'm slow.

 

[EBFD6]

You can put as many conductors in a raceway as the fill charts show.

However as soon as there are more then 3 current carrying conductors in a raceway you have to derate (reduce the rated ampacity) of the conductors.

Look at T 310.15(B)(2)(a). You can have 20 wires in a conduit-- you just need to derate after 3 CCC

You can put more than three in the conduit. You just can't use them to their full capacity. You must derate the ampacity of the current carrying conductors according to table 310.15(B)(2)(a)

Yeah, what they said!

 

[Jim W in Tampa]

you use the 90 degree value.

 

[infinity]

you use the 90 degree value.

If you have a 90 degree conductor.:grin: