C I Div 2

[charlie b]

I have long understood that if I have a room that has reasons to be classified CID2, that classification ends 18" above the floor. Thus, I do not need explosion-proof outlet boxes if they are installed higher than 18" AFF. But I can't find anything that confirms this. Is it right? Where would I find this in the code?

 

[nhee2]

The guidance for classification boundaries will generally be in the references listed in 500.4(B), and will depend on what the material or process that is within the room. Class I Div 2 might extend through the whole room (in the case of some natural gas installs) or only 18" from floor (for instance some repair garages). Article 511/513/514/515 do provide some area classification guidance for certain areas.

Note just because it is Div 2 does not mean all installation needs to be exp-proof either - those requirements are in 501.

 

[don_resqcapt19]

I have long understood that if I have a room that has reasons to be classified CID2, that classification ends 18" above the floor. Thus, I do not need explosion-proof outlet boxes if they are installed higher than 18" AFF. But I can't find anything that confirms this. Is it right? Where would I find this in the code?

It all depends on the actual area classification documents. In the factories I work at, often the complete inside of the building is Class I, Division 2.
The code does really define the area classification other than in the specific occupancies in Article 511 through 516.

 

[petersonra]

It all depends on the actual area classification documents.

Yep. I have never worked any place that was C1D2 where the classification only went up 18 inches, although often it stopped at some arbitrary height like 12 or maybe 15 feet.

I think that was just to make it easier.

 

[GoldDigger]

Certain specific locations, such as airplane hangars and garages, have defined areas such as up to 18" from the floor where receptacles and other potential spark sources are not allowed. You may be thinking of those provisions rather than the general C1D2 classification.

 

[charlie b]

This is a helicopter engine test facility. Fuel is pumped from a tank outside the building into the engine mounted on a test base. I think I can use 513.3(B).

 

[rbalex]

Using Section 513.3(B) is largely dependent on whether the location is adequately ventilated. You might also want to consider the area around the engine under test itself as an application of Section 513.3(C)(1).