Class II division I sealing question

[ltkogelmann]

I am in a power house running conduit from a non hazardous room through a block wall into a hazardous coal dust location, i ran 30' of conduit to an explosion proof motor, i have a seal off and a 2' piece of explosion proof seal tight. where does the seal off go?? thanks.

 

[augie47]

Not to answer your question with a question, but how are you addressing 430.102(B) ??

 

[kwired]

I am in a power house running conduit from a non hazardous room through a block wall into a hazardous coal dust location, i ran 30' of conduit to an explosion proof motor, i have a seal off and a 2' piece of explosion proof seal tight. where does the seal off go?? thanks.

Class II locations don't need a seal off.

You are not trying to contain an explosion if one should happen like you are doing for class I locations.

Difference is you are dealing with a dust and not a vapor. Vapor can still find its way into the raceway, motor, or other enclosure, dust is not as sneaky.

You do need a seal where you leave the classified area but this can simply be simple duct seal in the end of raceway in the first enclosure outside the classified area.

Your motor didn't necessarily need to be explosion proof - just rated for division II, and your flex could have been liquidtight flexible metal conduit as far as I know.

 

[rbalex]

To address Augie?s issue; both Exceptions to 430.102(B) will probably apply. See the FPN / IN No.1 for examples of ?increased or additional hazards? (classified locations).

Some additional comments to kwired?s post:

• Explosionproof equipment is neither required nor acceptable unless it is also specifically identified for Class II (Section 502.5)
• Boundary seals are not generally required at all as long as associated equipment is sealed in accordance with Section 502.15, which applies to both Class II, Division 1 and 2.
• The explosionproof motor you mentioned is probably also listed for Class II. Although it isn?t clearly stated, most totally enclosed motors with a NEMA Class B temperature rise will meet Section 502.125(A)(1). The term identified does not necessarily mean listed or labeled. It means ?recognized as suitable ...? See the definition of identified in Article 100 and Section 500.8(A) for Hazardous (Classified) commentary on Suitability. BTW See Section 500.8(B)(5) for some interesting commentary on normal as applied to motors.