Class-1 div-2 boundary seal

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Dsg319

Senior Member
Location
West Virginia
Occupation
(Green)Master Electrician
Anyways around having 2 boundary seals in this situation?

I have problems understanding the exceptions.

Conduit will not pass completely through the div-2 without a coupling or fitting.
 

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DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Anyways around having 2 boundary seals in this situation?

I have problems understanding the exceptions.

Conduit will not pass completely through the div-2 without a coupling or fitting.
Is it threaded rigid? Why would you not put the first seal before the underground submerges below grade?

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Dsg319

Senior Member
Location
West Virginia
Occupation
(Green)Master Electrician
Is it threaded rigid? Why would you not put the first seal before the underground submerges below grade?

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Yes it is, and the reason I drew both in the same area is because from where the conduit originated is from a remote I/O panel and will be full of other conduits and the seals will take more space.

I got to thinking though I could put one seal smack dab in the middle of the div-2 area as long as I can get a 10’ joint of conduit out both sides of the seal and extend beyond the boundary back to non-class.

That’s
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Yes it is, and the reason I drew both in the same area is because from where the conduit originated is from a remote I/O panel and will be full of other conduits and the seals will take more space.

I got to thinking though I could put one seal smack dab in the middle of the div-2 area as long as I can get a 10’ joint of conduit out both sides of the seal and extend beyond the boundary back to non-class.

That’s
If you're using threaded RMC and couplings and they are factory threads, you should only need one seal. The Steel Tube Institute states that factory threads and couplings (the one that comes with the length of conduit), when made wrench tight are acceptable in class 1 div 2 areas. I've done it many times and it passes around here. This is certainly a gray area though. Might be worth checking with the inspector to avoid rework.

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rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Except as it relates to the location of the seal(s), threading has nothing to do with the issue. Both indicated “boundary seals” are required UNLESS a single seal can be located within 10’ of both boundaries and no prohibited intervening fittings or devices (including “wrench-tight” couplings) are present between the seal and the boundary OR if Exception No. 4 possibly applies. That said, the seal(s) are not required to be explosionproof in any case.
 
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