Class 1 Division 1 501.15(A)(1) seals in dead end conduit?

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Hey all,

Been lurking the forum for a long time, great info. I have a question about the application of conduit seals in a Class 1 Division 1 space for a product we are manufacturing.

I have an explosion proof enclosure with a make/break contactor inside, so a sealing fitting for a conduit entry would be required by 501.15(A)(1)(1)

I have a single 1/2" conduit run out of the enclosure for only about 8" which ends at an explosion proof pressure transducer with an NPT electrical connection. The one fitting in the run is an explosion proof coupling (not the standard leaky straight thread sort). The cable on the transducer is factory sealed, and the transducer is NEMA 7 & 9.

The final 2 paragraphs of 501.15(A) indicate that a factory sealed "enclosure" is not adequate to count as a seal for a conduit run, and the next paragraph indicates that explosion proof fittings may exist between the explosion proof enclosure and the sealing fitting.

In my scenario, would a seal be required between the explosion proof enclosure and the explosion proof pressure transducer? The question I believe is whether or not this transducer constitutes a factory sealed enclosure or if it is considered more like a plug. I ask because plugging an NPT hole in an explosion proof enclosure with something other than a sealing fitting has already been accepted in my experience (our product had a few such plugs when we went through UL with it).

The safe answer is of course to include the sealing fitting, but we are running very tight on space here.

Thanks in advance for any help you may offer
 

rbalex

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Location
Mission Viejo, CA
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Professional Electrical Engineer
The primary enclosure must be sealed in compliance with Section 501.15(A)(1)(1). The solenoid cannot act as a "plug". Only a plug can act as a plug.
 
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