differnt voltages

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Jeff Rae

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can you run both 277/480 volt wireing in the same raceway as 120/208 volt what about the juction box any provisions?

[ August 31, 2005, 04:04 PM: Message edited by: Jeff Rae ]
 

charlie b

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Location
Lockport, IL
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Retired Electrical Engineer
Re: differnt voltages

The technical issue is that they must all have a voltage rating on their insulation systems that is at least as high as the lowest rated system. In this case, all of those conductors will have an insulation system rated at 600 volts. So I agree: "yup."
 

infinity

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New Jersey
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Re: differnt voltages

Didn't want to be short with my first answer got called away, but as Charlie had mentioned the insulation rating is one consideration and the the second consideration would be the identification of the neutrals.

Under the 2002 NEC the neutrals from different systems had to be identified by one systems' neutral having a stripe. This has been changed in the 2005 NEC whereas one system may have a neutral that is grey in color while the other has a neutral of white in color.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Re: differnt voltages

Originally posted by charlie b:
...they must all have a voltage rating on their insulation systems that is at least as high as the lowest rated system.
Mayhaps you meant highest?
 

charlie b

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Location
Lockport, IL
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Retired Electrical Engineer
Re: differnt voltages

I might have. In fact, I might have meant that all insulation systems must be rated for the highest circuit voltage applied to any conductor in the raceway. 300.3(C)(1).

That's one "attaboy" to Larry, and one "oops" to me. (Note: An "oops" is not as bad as an "ah-shoot," in that it doesn't erase all previous "attaboys.") :D
 
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