seal off's in class 1 div 1

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jmargolis79

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I have a 100 hp motor feed in a 2 inch imc pipe. From the starter it has a seal off the into the ground, a 90 the 8 feet of pipe the another 90 and back out of the ground. the into the motor with a flex fitting. Do I need a seal before the motor? I think I do because i am re-entering a class1 div 1 location after being under ground. Do I also need one to enter the motor houseing because it's a 2 inch pipe?
 
jmargolis79 said:
I have a 100 hp motor feed in a 2 inch imc pipe. From the starter it has a seal off the into the ground, a 90 the 8 feet of pipe the another 90 and back out of the ground. the into the motor with a flex fitting. Do I need a seal before the motor? I think I do because i am re-entering a class1 div 1 location after being under ground. Do I also need one to enter the motor houseing because it's a 2 inch pipe?
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Question for you is this motor and starter in the class 1 div 1 area . meaning is it all in the same room or hazards encompassing all electrical motor starter and just the underground conduit is out of the building ?

whats the hazard ?
 
The 2" entry does require a seal. See 501.15 (A)(1)(2).
Whether the underground is classified or not, is a matter of debate. It is generally accepted by the two most commonly use recommended practices (NFPA 497 and API RP 500) that it is Unclassified; but there are some that argue it is Division 1 or why even have 501.15 (A)(4) Exception 2 for general cases?
Ohmhead's point is still well taken; if both end's of the run are classifed because of the identical potential source or set of conditions, "boundary seals" at grade provide no additional protection.
 
I think I know what you're saying about the 2" requiring a seal, but need to clarify it in my mind. There will be a seal required at both ends per 501.15 (A)(1)(2), but only because of the 2" size, not for boundary sealing. Is the junction box on a Div 1 motor x-proof?
 
kameele said:
I think I know what you're saying about the 2" requiring a seal, but need to clarify it in my mind. There will be a seal required at both ends per 501.15 (A)(1)(2), but only because of the 2" size, not for boundary sealing. Is the junction box on a Div 1 motor x-proof?
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I'll assume your question was directed to me.

Only Section 501.15 (A)(1)(2), applies to the motor terminal box. A seal was required at the starter both for 501.15 (A)(1)(1) and (2). These are what I call integrity seals, since they maintain the explosionproof integrity of the enclosures involved, both starter and motor terminal box.

Division 1 motors do indeed have explosionproof motor terminal boxes.

For the installation as described, there is no benefit from boundary seals.
 
rablex,
Yes the motor has a internal seal. But as I understand that seal doesn't count for the boundry seal of the seal needed because of the the 2 inch pipe entry.
 
Since the internal seal is part of listed equipment, it's simply a feature of the listing and isn't any of the seals required by 501.15 (A).
 
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