3 three phase circuits cfrancka

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Can you put 3 three phase circuits in the same raceway?

I want to run three 30amp 3 phase ac circuits in the same raceway, do I need to de rate and if so how much?
 
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petersonra

Senior Member
Location
Northern illinois
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engineer
Can you put 3 three phase circuits in the same raceway?

I want to run three 30amp 3 phase ac circuits in the same raceway, do I need to de rate and if so how much?

what are you "derating" for? ambient temperature? number of current carrying conductors in the raceway?

what is your calculated load?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
22.2 amps per unit. I am asking do I need to derate for current carrying conductors?

Table 310.15(B)(3)(a) may be of some help. Also Table 310.15(B)(16).

Read carefully the second paragraph of 310.15(B).

Incidentally, instead of "calculated load" I should have asked what the required ampacity of your conductors is.
 

kwired

Electron manager
Location
NE Nebraska
note that if it is not possible to run all of your loads at the same time you can reduce the conductor count for application of 310.15(B)(3)(a).

2014 NEC even added text to the notes below the table to help clarify some of the situations that were questionable before, but they also added text indicating they want you to count spare conductors in the raceway - someday they might be used.
 
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