Voltage divider and 277 120 in same conduit question

I run into this sometimes, not as often as I have seen in the past. But I would see a single conduit have both the 277v and 120v circuit or switch legs or combination of both for 2 gang box with 2 switches. Problem here is that even though some 'try' to provide a divider for the 2 switches they sometimes end up cheating and modifying the divider because both circuits are in conduit and coming in on one side, versus have 2 separate conduits coming in on opposite sides.

This would be a NEC violation would it not?
 

don_resqcapt19

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Illinois
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retired electrician
Just choose the correct phases for the 120 volt and 277 volt circuits and the voltage won't exceed 300 volts between devices, so no divider required :D . Two of the 3 combinations exceed 300 volts between devices, but one is only 183 volts.
 
Just choose the correct phases for the 120 volt and 277 volt circuits and the voltage won't exceed 300 volts between devices, so no divider required :D . Two of the 3 combinations exceed 300 volts between devices, but one is only 183 volts.
LOL. that seems a bit much, and who could really be sure when on some installations they dont stay consistent with the color code so phase A can be black in one box then orange in another box. Better to just put a barrier or run a separate conduit.
 

ActionDave

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Licensed Electrician
You dont think this would be a violation of them bending it or drilling a hole in it to get to the other side, because they didnt run conduit for the other side? This seems to defeat the purpose of the barrier to me.
No. The divider is only for the switches. The conductors are allowed to be in the conduit and box. 300.3(C) specifically allows it.
 
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