Could you send me the Crouse Hinds link for this?All true above. Often times when you buy a classified disconnect or enclosure, it will be listed on the spec sheet as Nema 7/9. Which means it will work for Class I or Class II and is applicable for any division 1 or 2. Like they say above, pay close attention to the group listed such as A, B, C or D and make sure it meets your application.
If you are in a Class I area, that means there are explosive gases in the vicinity which means a spark could ignite the gas or even cause an explosion. If you are in a rated area, don't forget that you need threaded rigid conduit with seals. At least 5 threads for your threaded conduit. Keep in mind that sometimes there will be an explosion in your enclosure or disconnect or whatever the case may be. The explosion will cool off as it travels around the 5 threads in front of the seal which keeps the explosion contained and then releases harmlessly in the area. Typically no need to replace the enclosure or disconnect as it is generally a flash on the inside. Look in NFPA 497 for more information, it is all there.
Crouse Hinds also makes a great catalog which details how to properly install conduits in hazardous areas.