Conduit penetraiting a slab in a CLass 1 Div 1 area

[redwiggler]

My question relates to NEC Article 513.13 (B)...

(B) Areas Not Cut Off or Ventilated. The entire area of the hangar, including any adjacent and communicating areas not suitably cut off from the hangar, shall be classified as a CLass I, Division 2 or Zone 2 location up to a level 450 mm (18") above the floor.


Would this article prevent me from coming up through a slab with an unbroken conduit to height above 18" in order to avoid being in the Class I, Division 2 or Zone 2 location?

 

[lakee911]

I don't have the code section, but isn't there something that says in Class 1, Div. 2 one can pass a single continuous length of metallic conduit through the area w/o seal offs and without treating it like a typical hazardous area?

 

[johnmccoll]

As long as your wireway is continuous through your classification, you are not required to seal. In this case, your hazerdous location ends at 18" above the floor. You have passed through the classified area unbroken and are now in an unclassified area. This assumes that you are wiring in a hanger where that classification stops at 18". In a standard class I Div 2 building, the hazardous area is floor to ceiling.If as your title suggests, you are wiring in a class I Div 1 area, then the answer is no, that conduit must pass all the way through the building unbroken or must be properly sealed.

 

[kwired]

My question relates to NEC Article 513.13 (B)...

(B) Areas Not Cut Off or Ventilated. The entire area of the hangar, including any adjacent and communicating areas not suitably cut off from the hangar, shall be classified as a CLass I, Division 2 or Zone 2 location up to a level 450 mm (18") above the floor.


Would this article prevent me from coming up through a slab with an unbroken conduit to height above 18" in order to avoid being in the Class I, Division 2 or Zone 2 location?

Your area is likely class 1 div 2 but rules are basically same for both cases.

501.15(A)(4) covers div 1 and (B)(2) covers div 2 boundaries and seals.

Exception 1 to both those sections are nearly identical and say that if a metal raceway passes through the classified location with no unions, couplings, boxes or fittings no less than 12 inches beyond the boundary that a seal is not necessary. So if your boundaries are the floor and 18 inches above the floor then your first fitting(s) must be at least 12 inches below the floor and 30 inches above the floor. A coupling flush with the floor like concrete finishers like to see would not be acceptable.