Enclosure fan for Class 1 Div. 2

[jamesrw]

I have a control panel in a Class 1 Div 2 area that needs a cooling fan installed inside. 501.125(B) states " the installation of open or nonexplosionproof enclosed motors, such as squirrel cage induction motors without brushes, switching mechanisms, or similar arc producing devices that are not identified for use in a Class 1 Div 2 location, shall be permitted". I am not having any luck with the technical specs of different fans as to what type of motors they are using. Does anyone have any recommendations?
Thanks.
Jim

 

[rbalex]

This is a tough one to explain to even otherwise experienced electricians and engineers.

Essentially, motors are not required to be specifically listed or labeled for Class I, Division 2 applications. Many ?general purpose? motors are quite suitable; nevertheless not all are. Since it is not part a listing requirement, most manufacturers will not tell a user that their product is suitable or not for Class I, Division 2.

This leaves it up to the AHJ to determine the suitability. In general, most three-phase motors of standard NEMA design are suitable, most single-phase motors are not. Unfortunately, the process of selection beyond that initial generality can be extremely complicated. It takes someone familiar both with a specific motor?s design and Hazardous Locations to make the ultimate selection.

 

[petersonra]

I think the bottom line is that a cooling fan for use inside a control panel is unlikely to be suitable.

OTOH, no reason you cannot just pressurize the whole panel and make the inside of the panel non-hazardous and not have to worry about it. Might end up not even needing a fan anymore.

But, air is an expensive commodity.

One thing that some people have done is put the fan in a non-hazardous area and run duct work to the panel.