Raceway indoors to outdoors

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DAWGS

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Virginia
We are installing a feeder that is supplied from a switchgear inside one building running through that building, penetrating a wall, running about 6' through an outdoor vestibule, and back into another building. The buildings are not air conditioned, and should not have much difference between outside and indoor temperature difference. Would 300.7 come into play? What does the temp difference need to be were moisture will start to accumulate? Thanks.
 
excellent question !
I have no answer. I normally seal just to be "safe". The location of the conduits as they terminate does influence my decision (probably shouldn't), Conduite entering below live parts don't concern me as much as those above that "magic" line.
 
augie47 said:
excellent question !
I have no answer. I normally seal just to be "safe". The location of the conduits as they terminate does influence my decision (probably shouldn't), Conduite entering below live parts don't concern me as much as those above that "magic" line.
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They will enter above the magic line.:)
 
I wonder how far back that 300.7 starts off, " Where portions of a cable raceway or sleeve

are known-----". The 2008 and the 2005 both say, cable raceway,.

It's most likely a typo and should say, "Where portions of a cable, raceway, or sleeve--"
 
DAWGS said:
We are installing a feeder that is supplied from a switchgear inside one building running through that building, penetrating a wall, running about 6' through an outdoor vestibule, and back into another building. The buildings are not air conditioned, and should not have much difference between outside and indoor temperature difference. Would 300.7 come into play? What does the temp difference need to be were moisture will start to accumulate? Thanks.
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Are they heated during the winter?

If so, then I think they need to be sealed.
 
I would probably agree with John. Where you are I can imagine that the building could be 72 and the outside in the 30's. It's kind of like, how much expansion joint do you need?

And I also agree with augie, that it's an excellent question.
 
Augie,

I assume that you figure that the pipes are going to condesate anyways, so as long as it's not coming in above the buss, but below you don't worry about sealing it?

I would agree with that. Out here about the only time we really have to worry about it is when they install coolers.
 
as worded, it's definitely an AHJ type call. Coolers are about the only place I see it required also. From the condensation I have seen in "back-to-back" load center-meter installs, many of us should be more diligent in our enforcement of this Article.
 
Yes the buildings do have heat, very little just space heaters. One building is a chiller plant. the other is production. This leads me to another question. My feeder is parralell 2-1/2" conduits. Can I install Cee condulets before penetrating the walls? They will only be used for sealing and we will pull strait thru them not utilizing as a pull point.
 
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