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TEFC in Class 2 Div 2 Group G

TEFC in Class 2 Div 2 Group G

TEFC in Class 2 Div 2 Group G

I have an area classified as Class 2, Div 2, Group G for occasional dust.  We have plenty of TEFC motors in this area, but no XP motors.  Is this appropriate?  The only guidance I can find says TEFC motors are suited to dusty environments and that XP motors are only needed in Class 1 environments.  Class 2 is termed Dust Ignition Resistant.  
Then again, I have read that TEFC motors are not suitable in hazardous locations.  Am I OK with plain, generic TEFC?

Also, am I good to use a NEMA 4 enclosure, knowing that it is not suited in 'hazardous' locations, but is dustproof?  Do I need to go with NEMA 9 which is used for Class 2 Div 1 Group G even though I am in Div 2?

Thanks for your helpful response.

RE: TEFC in Class 2 Div 2 Group G

If you r location is Class-II, Division 2 ( not dust blanketed) you are allowed to use TEFC motors.

The USA NEC States for Motors and Generators; “Section 502-8(b). In Class II, Division 2 locations, motors, generators and other rotating electrical equipment shall be totally enclosed nonventilated, totally enclosed pipe ventilated, totally enclosed fan cooled or dust-ignition-proof for which maximum full-load external temperature shall be in accordance with Section 500-3(d) for normal operation when operating in free air (not dust blanketed) and shall have no external openings.”
“NEC Section 500-3(d) states: “ Class-I I  Temperature. The surface temperature marking specified in (b) above shall be less than the ignition temperature of the specific dust and in no case shall it be higher than the temperature given below for Groups E,F and G. ( See Clasification of Gases, Vapors, and Dusts for Electrical Equipment in Hazardous(classified) Locations NFPA 497M for minimum ignition temperatures of specific dusts.) “

RE: TEFC in Class 2 Div 2 Group G

That is about as good an answer as you are going to get. Bravo.

"Venditori de oleum-vipera non vigere excordis populi"

RE: TEFC in Class 2 Div 2 Group G

Thanks, aolalde.  That is quite helpful.    Can I use NEMA 4 enclosure?

RE: TEFC in Class 2 Div 2 Group G

First, aolade's response is solid. For what it's worth UL began listing motors specifically for Division 2 (Both Class I and II) sometime last year - they are NOT XP, Essentially, they are TEFCs that they have tested.

More info here:

Click on the "View Listings" in the upper left-hand corner for a list of the manufactures.

RE: TEFC in Class 2 Div 2 Group G

My personal opinion is that enclosures must be “Dust tight” not only NEMA 4.

The National Electric Code Section 502-6(b) “In Class-IÍ,  Division 2 locations, enclosures for fuses, switches, circuit breakers, and motor controllers, including pushbuttons, relays, and similar devices, shall be DUSTTIGHT.”

NEMA 250-2003 defines Enclosures Type 4 as “to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, and hose-directed water; and that will be undamaged by the external formation of ice on the enclosure.”

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