Selection of breather/drain for hazardous location conduits

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thebozak

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Jersey City, NJ, USA
First time posting to the forum, long time reader.

This is an NEC based question. Our typical design for a chemical plant install is Class I Div 2 area is with a type z purge/press control panel located in the hazardous area, non-incendive instrumentation, and insulated conductors in rigid galvanized steel conduit to connect. The only seals we install typically are at the control panel (to block purge flow, not necessarily to provide explosionproof protection) or at powered instrumentation when required. Voltages are typically 24VDC or 120AC for the power instruments.

At the bottom of all enclosures and vertical conduit runs, we typically install a Crouse-Hinds ECD18 "combination" breather/drain which is rated Class I Div 2 Group C,D. Are we overspecifying? Could this be an ordinary location breather drain?

If required to be hazardous rated per the area, can anyone suggest a suitable replacement (preferably a combination type) that would also cover Group B or CD + H2?

Thanks.
 
In my opinion, ordinary location drains are suitable for use in conduit runs in Class I. Division 2 locations. Drains in enclosures that are required to be explosion proof would also have to be explosion proof.
 
That was my interpretation. Explosionproof drains make for XP enclosures as they complete the protection of the enclosure. Once you are dealing strictly with conduit, ordinary listed fittings should suffice.

To go a step deeper, I would argue you could also apply this interpretation in Class I Div 1 as well. All arcing/sparking devices (including junction boxes) would be isolated from explosion with seals local to those enclosures.

Any thoughts?
 
thebozak said:
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To go a step deeper, I would argue you could also apply this interpretation in Class I Div 1 as well. All arcing/sparking devices (including junction boxes) would be isolated from explosion with seals local to those enclosures.

Any thoughts?
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I don't agree for Division 1 locations.
 
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