DERATING

[Toros]

Hi , would you find answers to this, I have to run about six dengerous, 120v conductors in 1" emt. Rule says that I have to derate the conductors down to propoer ampacity. My friend says, " Do not derate them, just increase the size of raceway to 2" emt" his statment or remedy contradicts my belif , is this true???

 

[GoldDigger]

The NEC rules on ampacity adjustments for multiple wires in a conduit do not say anything about size. You will have to derate in any case.
The fill rules, on the other hand, depend completely on conduit size and are totally separate from the ampacity rules.

 

[infinity]

As GD said conduit fill requirements are for installing the conductors into the raceway without damaging them and they have nothing to do with ampacity adjustment. Your friend is incorrect.

 

[GoldDigger]

In the other hand, if you have to increase the size of all of the wires because of ampacity adjustments, you might just run into the fill rule.

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