Seal offs where you're just 'passing through' art. 514

[nhfire77]

Situation is an Rigid Conduit Raceway- It begins as stub from in non-hazardous location up into a fueling station canopy and ends as a stub- without any fittings, couplings etc. it's carrying data cables.

514 classifies any raceway passing under a Class I Div. 2 area as a Class I Div. I until it exits the concrete.

Is there an exemption for an XP seal off when there is no break in the raceway, and it starts and end outside the boundaries? (Is 10' above the boundary in the canopy outside the boundary?)

Could it just be duct seal in a seal off for this situation?

 

[ptonsparky]

No break means no coupling...is the distance that short?

 

[nhfire77]

Ummm yea my bad, there are couplings it's 80 feet or so underground into a building. What I meant to type was no unions, boxes or fittings (other than couplings :ashamed.

 

[rbalex]

Tom (ptonsparky) asked the right question. However you will need a bit of history to understand my answer. Before the 2005 the NEC indeed "classifies any raceway passing under a Class I Div. 2 area as a Class I Div. I until it exits the concrete." That is no longer the case. Since 2005, Section 514.8 now reads:

514.8 Underground Wiring. Underground wiring shall be installed in threaded rigid metal conduit or threaded steel intermediate metal conduit. Any portion of electrical wiring that is below the surface of a Class I, Division 1, or a Class I, Division 2, location [as classified in Table 514.3(B)(1) and Table 514.3(B)(2)] shall be sealed within 3.05 m (10 ft) of the point of emergence above grade. Except for listed explosionproof reducers at the conduit seal, there shall be no union, coupling, box, or fitting between the conduit seal and the point of emergence above grade. Refer to Table 300.5.

The 2002 Figure 514.3 also indicated a Division 1 location below grade. The revised Figure 514.3 since 2005 has limited the Division 1 location to pits. This is consistent with more general practices.

If you are using an NEC version later than 2002 then grade is a "simple" Division 2/unclassified boundary and the rules of boundary sealing are whatever that particular version requires.

 

[nhfire77]

We are under the 2011 NEC. We have seal off fittings, what I am trying to understand is specially 501.15 that refers to the seal off not being XP, but the sealant being identified for its purpose of stopping the transmission of gases and vapor.

Other than a listed product such as Killark sealing compound, what products are regularly used as an "identified" product?

 

[rbalex]

...

Other than a listed product such as Killark sealing compound, what products are regularly used as an "identified" product?

Good question and CMP 14 hasn't seen fit to answer that directly. Many have considered "duct seal" in a common (non-explosionproof) conduit body as suitable. See Section 500.8(A)(3).

Note: If you use an explosionproof fitting, they are intended to be installed per Section 501.15(C) including 501.15(C)(2) and Section 110.3(B) may come into play. However, 501.15(C) Ex. does specifically exempt 501.15(B)(2). (That's why we have AHJ's )​

 

[Fulthrotl]

Situation is an Rigid Conduit Raceway- It begins as stub from in non-hazardous location up into a fueling station canopy and ends as a stub- without any fittings, couplings etc. it's carrying data cables.

514 classifies any raceway passing under a Class I Div. 2 area as a Class I Div. I until it exits the concrete.

Is there an exemption for an XP seal off when there is no break in the raceway, and it starts and end outside the boundaries? (Is 10' above the boundary in the canopy outside the boundary?)

Could it just be duct seal in a seal off for this situation?

IIRC, the first thing out of the ground is the seal off. no couplings first.
so any raceway exiting the ground needs a seal off in a CL 1 situation.
the other end will require one as well...