NEMA 4X enclosure in Cl II Div 2 area? dusttight?

[winslowfam]

Hi...code says that certain enclosures in a Cl II Div 2 area are required to be dusttight. Does a NEMA 4X stainless steel panel meet that requirement? Our client needs stainless, and area is Cl II Div 2.

Thanks !

 

[rbalex]

Hi...code says that certain enclosures in a Cl II Div 2 area are required to be dusttight. Does a NEMA 4X stainless steel panel meet that requirement? Our client needs stainless, and area is Cl II Div 2.

Thanks !

NEMA 4X alone is not dusttight; fortunately, many such enclosures are multiple rated. See the notes for Table 110.28 for other alternates.

 

[winslowfam]

Hoffman has published a "Classification of Hazardous Locations" document that has the following statement: "Dust-tight Enclosures. As defined by UL 50 and NEMA 250, dusttight enclosures are Types 3, 4, 4X, 12, 12K, and 13". Are they speaking only about their enclosures?

 

[rbalex]

As I mentioned, most Type 4X have multiple ratings. Did you bother reviewing Table 110.28 as I suggested?

 

[winslowfam]

Yes, I did...and now just got what you meant. I can specify a dual-rated enclosure, NEMA 4X/12... Is that what you were driving at?

 

[templdl]

Attached are the NEMA enclosure ratings

 

[templdl]

Attached is an explosion Proof classification document

 

[rbalex]

Attached is an explosion Proof classification document

I don't know the source of the document, but it appears to be unfamiliar with Section 502.5. Now if it were titled "Hazardous (Classified) Location Classifications" it would be relatively accurate.

 

[rbalex]

Yes, I did...and now just got what you meant. I can specify a dual-rated enclosure, NEMA 4X/12... Is that what you were driving at?

Yes. Sorry about the tardy response, I had some pressing business to attend to.

 

[templdl]

I don't know the source of the document, but it appears to be unfamiliar with Section 502.5. Now if it were titled "Hazardous (Classified) Location Classifications" it would be relatively accurate.

I may not be aware that there are different set of Classes, Divisions, And groups classifications for the NEC other than the ones that I had posted.
I was to understand that one needs to first identify the classification of the area that the enclosure is to be located in first and then source an enclosure that is listed for that area and installed as directed per the NEC but I may be mistaken.

Class II Locations: Are those which are hazardous due to the presence of combustible dust.
Division I Locations in which hazardous concentrations in the air exist continuously, intermittently, or periodically under normal operating conditions.
Division II Locations in which hazardous concentrations are handled, processed, or used but are normally within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown.

 

[rbalex]

I may not be aware that there are different set of Classes, Divisions, And groups classifications for the NEC other than the ones that I had posted.
I was to understand that one needs to first identify the classification of the area that the enclosure is to be located in first and then source an enclosure that is listed for that area and installed as directed per the NEC but I may be mistaken.

Class II Locations: Are those which are hazardous due to the presence of combustible dust.
Division I Locations in which hazardous concentrations in the air exist continuously, intermittently, or periodically under normal operating conditions.
Division II Locations in which hazardous concentrations are handled, processed, or used but are normally within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown.

If I'm just being grumpy, please forgive me.Today has been a tough one.

If you read Section 502.5, you will see that explosionproof equipment is neither required nor alone accepted in Class II locations. The somewhat Class II analog is dust-ignitionproof. The distinction between them is in Section 500.2 Definitions.

 

[winslowfam]

I really appreciate your comments, Bob...it has cleared it up for me. appreciate it.

 

[kwired]

If I'm just being grumpy, please forgive me.Today has been a tough one.

If you read Section 502.5, you will see that explosionproof equipment is neither required nor alone accepted in Class II locations. The somewhat Class II analog is dust-ignitionproof. The distinction between them is in Section 500.2 Definitions.

To add a little to what Bob said here:

Getting the terminology correct is especially important when trying to interpret rules for classified areas.

The source of the hazards is completely different between class I and class II locations, and does have some impact on some of the terms as well as installation practices commonly used for each.

 

[templdl]

If I'm just being grumpy, please forgive me.Today has been a tough one.

If you read Section 502.5, you will see that explosionproof equipment is neither required nor alone accepted in Class II locations. The somewhat Class II analog is dust-ignitionproof. The distinction between them is in Section 500.2 Definitions.

Grumpy? Not a chance. Sometimes it takes a bit to get tuned in to the same wave length is all. It's all about seeing the light and understanding what one another is referring to.

 

[rbalex]

To add a little to what Bob said here:

Getting the terminology correct is especially important when trying to interpret rules for classified areas.

The source of the hazards is completely different between class I and class II locations, and does have some impact on some of the terms as well as installation practices commonly used for each.

I appreciate your addendum. The somewhat subtle difference is that explosionproof (typically Type 7) cannot exclude gasses and vapors, dust-ignitionproof (typically Type 9) can and must exclude dusts. Fortunately, for Division 1 of their respective Classes many enclosures meet the criteria for both.

 

[rbalex]

Grumpy? Not a chance. Sometimes it takes a bit to get tuned in to the same wave length is all. It's all about seeing the light and understanding what one another is referring to.

Thanks for your kind words. This is my preferred reference document for NEMA Type enclosures. It come "straight from the horse's mouth" so to speak and is a free download for the trouble of giving them your email address.

EDIT ADD: BTW you will note both Types 7 and 9 are for indoor use only; they must have additional "outdoor" markings to be used outdoors. Again, fortunately most such enclosures have such markings.

 

[templdl]

Thanks for your kind words. This is my preferred reference document for NEMA Type enclosures. It come "straight from the horse's mouth" so to speak and is a free download for the trouble of giving them your email address.

EDIT ADD: BTW you will note both Types 7 and 9 are for indoor use only; they must have additional "outdoor" markings to be used outdoors. Again, fortunately most such enclosures have such markings.

I know that I have a copy of that document somewhere in a place that I couldn't loose it but filed away so good that I can't find it either.
I'm filing the PDF that you attached in my electronic tech. File.
Thanks