ryan_618
Senior Member
- Location
- Salt Lake City, Utah
For a product (J-box)to be identified (or listed) as suitable for group E locations (Class II), does the enclosure need to be dust-ignition proof, or just dust tight?
Group "E" listing
- Thread starter ryan_618
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bphgravity
Senior Member
- Location
- Florida
Re: Group "E" listing
The code seems to indicate that dust ignitionproof boxes are a permitted technique for Division I and II locations, whereas dustight equipment is only permitted for Division II locations. My reference is 500.7(B)&(C).
The code seems to indicate that dust ignitionproof boxes are a permitted technique for Division I and II locations, whereas dustight equipment is only permitted for Division II locations. My reference is 500.7(B)&(C).
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Group "E" listing
I agree Bryan, but 500.7 is simply addressing protection techniques. Take a look at this:
I agree Bryan, but 500.7 is simply addressing protection techniques. Take a look at this:
There are rules that govern sealing if the box is required to be dust-ignition proof. So, if I am working in a group E class I division I location, I must seal if the box (for splices only) is required to be dust-ignition proof. If the box is only required to be dusttight, I wouldn't have to seal. I need to know what the the listing difference is between a group "E" and groups "F" and "G". Does that make any sense?
- Location
- Illinois
- Occupation
- retired electrician
Re: Group "E" listing
Ryan,
Just don't forget that you don't need any special fittings in most cases in Class II locations. The conduit itself can be the seal in many cases. See 502.5.
Don
Ryan,
Just don't forget that you don't need any special fittings in most cases in Class II locations. The conduit itself can be the seal in many cases. See 502.5.
Don
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Group "E" listing
Don, thank you, I agree. I am working on one of Mike's books right now to create/modify a graphic that shows exactly what you are talking about.
If I have a junction box located above a switch, the switch will have to be dust ignition proof. The J-box, however, needs to be identified as being suitable for a group "E" location. So, I need to seal between enclosures if one is required to be dust-ignition proof and the other is not required to be dust-ignition proof.
I am trying to figure out if a seal is needed in the above applicaiton, and that would be a function of whether or not the J-box is required to be dust-ignition proof, or just dust tight.
Thanks again,
Don, thank you, I agree. I am working on one of Mike's books right now to create/modify a graphic that shows exactly what you are talking about.
If I have a junction box located above a switch, the switch will have to be dust ignition proof. The J-box, however, needs to be identified as being suitable for a group "E" location. So, I need to seal between enclosures if one is required to be dust-ignition proof and the other is not required to be dust-ignition proof.
I am trying to figure out if a seal is needed in the above applicaiton, and that would be a function of whether or not the J-box is required to be dust-ignition proof, or just dust tight.
Thanks again,
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Re: Group "E" listing
Ryan,
I apologize for getting back so late. I haven't been able to log in as often lately.
I?m citing the 2002 NEC, so you will need to correlate the 2005 Sections.
A simple junction box need only be dusttight in Class II, Division 2 under the general rule. See 502.4(B)(4)
Enclosures that are required to be dust-ignitionproof are relatively limited: 502.6(1), 502.7(A), and 502.7(B)(2).
Note: in all three cases the enclosure is only required to be identified as dust-ignitionproof, not necessarily listed nor labeled for it. This is one of the few cases where I personally think CMP14 should have made listing or labeling a specific requirement. I've been working with this stuff for years and still wouldn't feel qualified to "identify" an enclosure as dust-ignitionproof without a NRTL certification.
Section 502(8)(B) permits dust-ignitionproof as one of several alternates, thus it is NOT required to be.
Ryan,
I apologize for getting back so late. I haven't been able to log in as often lately.
I?m citing the 2002 NEC, so you will need to correlate the 2005 Sections.
A simple junction box need only be dusttight in Class II, Division 2 under the general rule. See 502.4(B)(4)
Enclosures that are required to be dust-ignitionproof are relatively limited: 502.6(1), 502.7(A), and 502.7(B)(2).
Note: in all three cases the enclosure is only required to be identified as dust-ignitionproof, not necessarily listed nor labeled for it. This is one of the few cases where I personally think CMP14 should have made listing or labeling a specific requirement. I've been working with this stuff for years and still wouldn't feel qualified to "identify" an enclosure as dust-ignitionproof without a NRTL certification.
Section 502(8)(B) permits dust-ignitionproof as one of several alternates, thus it is NOT required to be.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Re: Group "E" listing
You know I've been just too tired to read the question carefully. (I overlooked the "Group E" qualification.)
Group E is always Division 1 (502.1) if classified at all and a J-box needs to be "identified" for Group E - 502.4(A)(1)(d); however this is not necessarily "listed." In this case the issue is two-fold. Will ignitable dusts reasonably enter the enclosure AND since they are metallic will they likely become the cause ignition themselves.
"Dusttight" is usually enough to answer both questions. In this case, it is "identification" enough if there are no other reasonable entry paths through the raceway.
[ June 09, 2005, 05:35 PM: Message edited by: rbalex ]
You know I've been just too tired to read the question carefully. (I overlooked the "Group E" qualification.)
Group E is always Division 1 (502.1) if classified at all and a J-box needs to be "identified" for Group E - 502.4(A)(1)(d); however this is not necessarily "listed." In this case the issue is two-fold. Will ignitable dusts reasonably enter the enclosure AND since they are metallic will they likely become the cause ignition themselves.
"Dusttight" is usually enough to answer both questions. In this case, it is "identification" enough if there are no other reasonable entry paths through the raceway.
[ June 09, 2005, 05:35 PM: Message edited by: rbalex ]
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Group "E" listing
Thanks for your input, Bob. I agree with you that the code should require a listed product for this application. I am going to try to contact UL about this, and see what they have to say.
Thanks again
Thanks for your input, Bob. I agree with you that the code should require a listed product for this application. I am going to try to contact UL about this, and see what they have to say.
Thanks again
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