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Discussion Starter · #1 ·
I have experience with class 1 (gas) but am new to working in class 2 (dust). Although i've read section 18 of the CEC about 15 times already, I'm having a hard time getting it straight in my mind as to what's acceptable.

If someone can help explain some things in simple terms that'd be great. Specifically I'm looking to find out the wiring methods differences between class 2 zone 21 and class 2 zone 22.

If its zone 21 do you need EXP enclosures (ones with thick bolt-on covers) or can you use an enclosure with metal latches on the cover? And what about in zone 22?

Also, the way I'm reading this I'm understanding that if you were to have an enclosure in a class 2 zone 22 location and inside the enclosure had circuit breakers and contactors you would be required to pack/pour seals on every cable/conduit entering that enclosure. Am i reading that right?

Since I'm new to working around grain dust I could use some insight. I know that its still a hazardous location but I'm not sure how different it is from a gas plant or oil facility when it comes to enclosures and cable/conduit seals.

Thanks in advance!
 

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Sealing is different than Zone 1 or 2..

18-204 Sealing, Zone 21
Where a raceway provides communication between an enclosure that is required to be dust-tight and one that is not, the entrance of dust into the dust-tight enclosure through the raceway shall be prevented by
(a) a permanent and effective seal;
(b) a horizontal section not less than 3 m long in the raceway; or
(c) a vertical section of raceway not less than 1.5 m long and extending downward from the dust-tight enclosure.

They've also dropped the "Class 2" and it is now just Zone 20, 21 or 22....

All the Zone 22 places I've done have been gasketted condulet fittings, rigid conduit or teck cable..
 

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Discussion Starter · #3 ·
So are you saying the common practice should be pouring an eys seal (or something to the same effect) going into a contactor cabinet that is located in a zone 21 location? Thats what i would think, but i just don't know if thats actually whats being installed in newly built sites.
 
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