class 1, div 2 devices in class 2 div 1 location

[jimmy_mcquade]

Hi all,

I saw dad pulling out the code book looking at the hazardous section and i started
asking questions. Now i am studying the hazardous code.

Dad showed me the ul rating certificate number for a design he is doing. i then went to the website and started reading.

My question is this, is a class 1 div 2 device such as a pushbutton ok to use in a class 2, div 1 area? i read in 500.7D that a purged/pressurized system would make
devices acceptable for the envorinment for devices that are not listed for the environment so i am going to say yes.

But would they be acceptable if you didn't have a purge/pressurized system?
Class 1 is a gas, but this is a class 2 dust. Doesn't the class 1 requirements make it satisfactory for class 2 since its more strict?

thanks in advance,
jimmy

 

[rbalex]

Possibly, but not necessarily. The basic rule is Section 500.8(B)(1): “Equipment shall be identified not only for the class of location but also for the explosive, combustible, or ignitable properties of the specific gas, vapor, dust, or fibers/flyings that will be present...” The rest of the Section outlines temperature restrictions of each of the various Classes (I, II, or III) The temperatures are a separate issue and, if you compare, Section 500.8(D)(2) requirements with 500.8(C) you will find the maximum permitted Class II temperature is below most of those permitted in Table 500.8(C).

 

[jimmy_mcquade]

thanks,
jimmy