conductors from two services, 277 and 120V in same box

I have a 277/480 and a 120/240 three phase delta service. I plan to install a 277V and a 120v receptacle in the same box. Other than color coding requirements, any other issues to be aware of? I think that requirement for voltage between adjacent switches has me paranoid.....
 

MD84

Senior Member
Location
Stow, Ohio, USA
I think in that case all ungrounded conductors need to switch off together. I may be confusing that with same yoke vs same box. Not quite an easy proposition. Let me check....

406.5(H) voltage between adjacent devices shall not exceed 300v

I would think you are good there
 
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Damn you guys, you ruined my plan, thanks a lot ;) So that would preclude even two 277V receptacles fed from a MWBC in the same box. I was aware of the 404 article, but didnt know the same thing was in 406. If one really wanted to get cute, with different systems I believe the voltage could be kept below 300 with proper phasing. IF there is a 30 degree phase shift on one system due to the transformer arrangement, that would make things interesting. Ill have to do the math on that one.....
 
No, that would be allowed because it would have a single disconnecting means due to the handle tie requirements for MWBCs.
That would be a separate issue than the voltage between devices requirement no? Oh, you must be imagining a duplex receptacle with each half fed from a MWBC. I meant 2 single (or duplex) receptacles, each fed from a MWBC.
 

jap

Senior Member
What if you pulled (2) neutrals and kept the (2) 277v circuits on the same phase ?
You should be able to do that legally in the same box.


JAP>
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
What if you pulled (2) neutrals and kept the (2) 277v circuits on the same phase ?
You should be able to do that legally in the same box.
That would work since the voltage between them would be zero.
 

MD84

Senior Member
Location
Stow, Ohio, USA
I have seen those and would think they fit the purpose but they are always described as a partial for voice/data. The catalog page indicates they are NOT UL listed.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
I have seen those and would think they fit the purpose but they are always described as a partial for voice/data. The catalog page indicates they are NOT UL listed.
There is no requirement that the divider be a listed product. There is not even a general requirement that says the box and plaster ring has to be listed.
 
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