surface light feed in a class1 div 2 ceiling

[ajfoyt]

I am roughing in lighting feeds for surface lights in a class 1 div 2 ceiling in a lab. Can I just put in 4 square boxes with a plaster ring in the ceiling or do I have to run rigid or seal-tight on the surface to all the fixtures after the seal off?

 

[rbalex]

As always, you need first to have proper electrical classification documentation. [Section 500.4] Once you have identified the proper classification(s), you are permitted to install any wiring method and equipment approved for that location. SO, what is the electrical area classification that the surface lights are actually in? Is that wiring method suitable for Class I, Division 2? [See Section 501.10(B)] There are a few cases where wiring and equipment above a classified location must be special, but that is generally not true for laboratories.

 

[ajfoyt]

Thanks for your reply rbalex. The room is classified as a class 1, div 2. It's a 35' by 25' area with outside walls. I think what I will do is run bell boxes outside and go to the inside with a rigid nipples with a seal off.

 

[rbalex]

The seals are probably overkill. Are the luminaires suitable for Class I, Division 2? [See Section 501.130.]

 

[ajfoyt]

Yes they are Paramount Industrial for Class 1 Division 2. I thought because I was penetrating the wall barrier to go outside the room I would need a seal off.

 

[rbalex]

You are correct - the seal is probably appropriate; however, it doesn't have to be explosionproof. [See especially the last sentence of Section 501.15(B)(2) (but read the whole main text)]