Class II Conduit Sealing

[filterengineer]

I'm new to this forum and appreciate everyone's help!

I have an installation where we are installing new equipment in a Class II, Div 1, Group G location. Conduit will pass through a wall into a Class II, Div 2, Group G location.

We are installing dust-ignitionproof (NEMA 9) enclosures in the Div 1 location. We are installing dusttight (NEMA 12) enclosures in the Div 2 location. Per 502.15, we are required to seal the conduit between the Div 2 and Div 1 location. Do we only have to seal that (those) conduits passing between the Div 1 and Div 2 locations, or do we also have to seal conduits running between dust-ignitionproof enclosures in the Div 1 location?

Also, where should the seal be installed in the conduit between the Div 1 and Div 2 locations? At the enclosure located in the Div 2 area or at the enclosure located in the Div 1 area? Is there a spacing requirement?

 

[rbalex]

You cited the correct Section (502.15), but incorrectly. Reread all of it carefully. There is no classified ?boundary? condition as in Class I locations.

The key is preventing dust from entering the dust-ignitionproof enclosure through the raceway. Section 502.15 lists several acceptable methods. If you can use 502.15 (2) through (4) that?s best. Technically the seal, if necessary at all, can be anywhere in the raceway and they don?t need to be explosion proof.

Note: if the raceway extends all the way to a nonclassified location a seal isn?t necessary at all (where would the dust be coming from )

 

[filterengineer]

Thanks for the response. I should have been more clear in my question. There are several locations where I cannot use the methods described in 502.15 (2) through (4). In those locations, I will have to use method (1). The lack of a boundary condition was throwing me. Thanks for clarifying.

Am I correct that conduit between dust-ignitionproof enclosures located in a Div 1 area does not have to be sealed?

 

[rbalex]

...
Am I correct that conduit between dust-ignitionproof enclosures located in a Div 1 area does not have to be sealed?

That would be correct.