How to calculate.

[bora43]

How many current carrying conductors #12 THHN can be install in 1" EMT, based on derating factors. What is the best way to calculate?

 

[roger]

Go to chapter 9 for conduit and wire dimensions, the number of conductors allowed in the conduit will be the same regardless of any derating.

Roger

 

[Eastham11]

Also, don't forget to derate for temperature as applicable to the location, and for neutrals if the load is non-linear.

 

[bora43]

How to calculate

How to calculate

I installed 20 #12 THHN in 1" EMT 10 ckts, all dedicated. Inspector sad that I violated the NEC. He sad it should be no more then 4 #12 conductors in 1" EMT because of derating factor. Any one knows the answer?

 

[chris kennedy]

I installed 20 #12 THHN in 1" EMT 10 ckts, all dedicated. Inspector sad that I violated the NEC.

See T310.15(B)(2)(a) if you have them all on 20A breakers.

He sad it should be no more then 4 #12 conductors in 1" EMT because of derating factor.

My guess is he meant 4 circuits with their own neutrals.

 

[roger]

My guess is he meant 4 circuits with their own neutrals.

That would be my guess as well.

Roger