501.15(B)(2) Class 1, Div 2 Boundary Seal Requirement

[Richard S]

We have a situation where EMT (20' segment) passes completely through a Class 1, Div 2 area without any couplings, boxes or fittings within 12" of each boundary. 501.15(B)(2) Exception No. 1: states that "Metal conduit that contains no unions, couplings, boxes, or fittings, and passes completely through a Class I, Division 2 location with no fittings less than 300 mm (12 in.) beyond each boundary, shall not require a conduit seal if the termination points of the unbroken conduit are in unclassified locations."
Since EMT is steel (metal), this would appear to be acceptable, but I'm not sure if they are implying rigid metal conduit. 358.18(4) EMT Uses not permitted, states "not in any hazardous location except as permitted by other articles of this Code." This is vague and doesn't help.

Any comments or experience??

 

[rbalex]

Unfortuately, EMT simply isn't an acceptable wiring method in Division 2 except for a nonincendive or intrinsically safe application, seals or not. See 501.1(B)(1) and compare with 501.1(B)(3) or 504.20.

I guess with the addition of RTRC in 501.1(B)(1)(7) the Exception is due for a revision - THANKS for the Proposal material.

 

[IamJonscranium]

Unfortuately, EMT simply isn't an acceptable wiring method in Division 2 except for a nonincendive or intrinsically safe application, seals or not. See 501.1(B)(1) and compare with 501.1(B)(3) or 504.20.

I guess with the addition of RTRC in 501.1(B)(1)(7) the Exception is due for a revision - THANKS for the Proposal material.

Assuming you mean 501.10. (2008)

Does the no EMT rule apply since it is passing through unbroken? I would think Class1 Div2 wiring methods would not apply since it isn't wired inside the classified area.

 

[rbalex]

Assuming you mean 501.10. (2008)

Does the no EMT rule apply since it is passing through unbroken? I would think Class1 Div2 wiring methods would not apply since it isn't wired inside the classified area.

You're correct; I should have cited Section 501.10 (B)(1) rather than 501.1(B)(1). Nevertheless, when a wiring method passes through a Division 2 location, it is also in the Division 2 location and is not recognized unless it is part of an nonincendive or intrinsically safe installation.

 

[petersonra]

I say cut it off before it gets to the classified area and change to IMC or rigid.

Having said that, it seems like an odd requirement given it is a div 2 area and it is an unbroken chunk of EMT. I don't see how gases could ever get into the chunk of EMT.