Instrument Enclosure and JB Breather and Drain

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Thread Starter

Utz

Please check the below sentence as our Client requirement.

"Instrument enclosures and junction boxes having an internal volume exceeding 2,000 cm³ shall be provided with Type 300 Series stainless steel breather and drain fittings, or a combination."

Why it is so? I mean what is the purpose of breather and drain? Why only JB with volume exceeding 2,000 cm³ requires those?

 
Typically it is to drain condensation that can collect in the bottom of the panel if the air is damp (and sometimes not so damp). I even have that problem once in a while here in Phoenix.

The surface area specified is just to minimize cost factors on small panels where this is not as much of a problem. Since the amount of condensation is dependent on the surface area exposed, the larger panels have more water than can condense. The breather is simply to easily allow the moisture to exit if the door gasket really does make a tight seal.

Russ
 
A lot of thanks for the answer.

I would like to know if it has no impact against the hazardous gases around the JB/Panel. I mean, perhaps the breather and drain could degrade its protection preventing explosion on the plant.
 
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Bruce Durdle

If the panel is flameproof or explosion-proof, then any breather or drain needs to be certified accordingly. You cannot fit a non-certified breather or drain to a certified panel without invalidating the certification.
 
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