Exterior Class1,div1&2 Ac Panel

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This is a two part question:
A customer is requesting a Killark panelboard (B7 series) to be installed in a Class1, Div2 location. They want it mounted on the exterior. This is where i'm getting confused.....

The panel is rated for Class1, Div1&2, Groups B,C,D; It also is listed under Nema3/4/4X (non-classified) and Type 7 & 9 (classified location).
Type 7 & 9 are indoor use, while Type 8 is indoor/outdoor. However, are Type 8 enclosures still available? I've seen charts that include Type 8 and charts that go from Type 7 to 9. My main concern is that those outdoor use ratings (3/4/4X) are ?non-classified? location ratings. Since this project has called for Class1, Div2 equipment all along, should the enclosure be rated for outdoor ?classified locations? (Type 8), or is the fact it's rated for Class1, Div1&2 AND outdoor rated (although under non-classified location), will this AC panel meet the code requirements or should we add a disclaimer? They are saying NEMA 7 is good for outdoor, and they have NEMA 7 outdoor all over the place. I don't want to 'over-analyze' but something just doesn't sound right and at a cost of >$11,000, I want to make sure this panel can be installed outdoors in a hazardous location. Any help would be greatly appreciated.
 

rcwilson

Senior Member
Location
Redmond, WA
NEMA 7 Outdoors

NEMA 7 Outdoors

In my refinery experience about 95% of the NEMA 7 equipment was outdoor.

I would be suprised that a NMEA 7 device could not be used outdoors.
 

don_resqcapt19

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Location
Illinois
Occupation
retired electrician
Bob,
I would be suprised that a NMEA 7 device could not be used outdoors.
If you want to use it outside it must also have a NEMA 3R, 4 or 4X listing. The finished surfaces on many NEMA 7 devices are not water tight. When they get wet and rust, the joint may not be able to do its job....drop the pressure of the expanding gases from the internal explosion enough to cool them below the auto-ignition point of the flamable gasses outside of the enclosure. Some NEMA 7 fittings have a O ring or other gasket to make them NEMA 4 while the threads of finished surface joint makes them NEMA 7. Note a quick check of the Appleton online catalog shows that most of the NEMA 7 and 9 devices are also rated 3, 3R, 4 or 4R, but not all are,
Don
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Each NEMA ?Type? is a separate designation and means the enclosure has been examined for a specific set of conditions. Where an enclosure has been given multiple ?Type? recognitions it has been found suitable for all the conditions (sometimes they overlap) associated with each type.

If the enclosure were ONLY recognized for ?Type 7? it would be limited to indoor use. But, where it has recognition for other ?outdoor? types also, then it may also be used outdoors.
 
rbalex said:
Each NEMA ?Type? is a separate designation and means the enclosure has been examined for a specific set of conditions. Where an enclosure has been given multiple ?Type? recognitions it has been found suitable for all the conditions (sometimes they overlap) associated with each type.

If the enclosure were ONLY recognized for ?Type 7? it would be limited to indoor use. But, where it has recognition for other ?outdoor? types also, then it may also be used outdoors.
Thanks, Bob. You helped it make sense!
 
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