spray booth applications

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sparky91

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hi all , fairly new here , question is i was asked to wire 4 fan motors in an auto body spray booth. They will be mounted in each corner of the spray booth as high as possible in the corners---installation will be done by the vendor not me .
Vendor tells me the fans are manufactured totally explosion proof. There will be 4 fans, each one is half hp, 3 phase 208, 2 amps each. I want to put one disconnect for ALL 4 motors. If i install the disconnect INSIDE the spray booth it will eventually get caked with paint. If im correct the disconnect has to be 25 feet within site of the motors. Is there any way i can mount the disconnect outside the spray booth and be LEGAL. I could probably mount 1 disconnect at each motor, but that would leave me with the same predicament with paint residue and it would probably cost me alot more for explosion proof stuff. And if i can mount it outside the spray booth ,do i have to mark where the disconnect is , or maybe lock the disconnect.
thank you for reading folks
 
I don't think the manufacturer would allow it inside. I am just starting to digest info on a privately owned unit that I will be wiring. For starters, nothing but explosion proof equipment within 3' of any door entering the actual unit.

I would contact the AHJ (firemarshall?) and the manufacturer to make sure you are up to speed on everything.
 
The "within sight" is 50 feet, and for a disconnect that is not lockable.

You could have your disconnect on another floor with the right lockable equipment. And yes, well labeled
 
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This sounds like a very unusual installation. It is common practice to locate all the electricals outside of the spray booth whenever possible. And better yet outside of the Division 2 areas as well. The cost of installing and maintaining explosionproof equipment is horrendous. Yes, it will get covered with overspray. I have been involved with spray finishing for years, but have never seen a booth such as you describe. It might be a wonderful design or a total disaster. If the exhaust fans and motors are not protected by effective filtration, they will quickly become coated with overspray and fail to operate as intended or worse (probably worse).

Please take a good look at NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials. The current edition is 2007.
 
This application falls within Section 430.102(B) Exception as condition (a). You can definitely mount the disconnect outside the booth; however it is the controller disconnect that must be lockable - not the motor disconnect. Read Section 430.102 carefully in its entirety. It isn't that long, but it is critical to understand it.

I'll defer to sgunsel with regard to the overall design - it does sound unusual, but depending on the manufacturer, I just may not be "picturing" it correctly.
 
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