Awilson2s
Member
- Location
- Columbia, IL, USA
Newbee here looking for a little direction and a better grasp of Hazardous environment code.
I am working on a panel design that will house 2 racks of FLEX Thermocouple modules the area the panel will be located is a Class 2 Div 2 Group G area as determined by the plant. There will not be much heat dissipation from the components so temperature will not be an issue. The dust i am dealing with is Flour.
I am trying to decide my best option for an enclosure. I am looking into NEMA 9, Standard Dust Tight such as a NEMA 12, or a purged/pressurized enclosure.
I would like to use unclassified components inside the enclosure as the plant already stocks the standard FLEX modules and i would prefer not to use the FLEX EX modules and other non standard parts if it isn't necessary.
Please correct me if any of this is wrong im here to learn.
I can use a general purpose enclosure and a purging/pressurizing system to create an area inside the enclosure that is now considered to be "unclassified" therefore the electrical components i specify to be mounted inside do not need to be rated for a class 2 div 2 environment.
I see in 500.7(C) that dust tight enclosures are accepted as a protection technique. By not allowing dust in the enclosure is this area still considered class 2 div 2? are the components required to be class rated?
I have seen other postings online saying that you can use a NEMA 9 enclosure and use non class rated components but dont see this in the code. Can anyone point this out to me if this is so?
My current thoughts while approaching this is that i have an area that is Class 2 div 2. If i want to use parts that are not rated for this i need to create an environment that is unclassified. is this the best way of looking at it? This thought process has brought up my next question. When the door of the enclosure is open the area is Class 2 Div 2 do i need to supply an alarm or door switch to kill power to the panel when the door is open and if i go with a purging/pressurized system when the panel loses pressure? I probably need to browse through NFPA 496 more for answers to the pressurizing system but any direction you can give is much appreciated.
Thanks in Advance!
I am working on a panel design that will house 2 racks of FLEX Thermocouple modules the area the panel will be located is a Class 2 Div 2 Group G area as determined by the plant. There will not be much heat dissipation from the components so temperature will not be an issue. The dust i am dealing with is Flour.
I am trying to decide my best option for an enclosure. I am looking into NEMA 9, Standard Dust Tight such as a NEMA 12, or a purged/pressurized enclosure.
I would like to use unclassified components inside the enclosure as the plant already stocks the standard FLEX modules and i would prefer not to use the FLEX EX modules and other non standard parts if it isn't necessary.
Please correct me if any of this is wrong im here to learn.
I can use a general purpose enclosure and a purging/pressurizing system to create an area inside the enclosure that is now considered to be "unclassified" therefore the electrical components i specify to be mounted inside do not need to be rated for a class 2 div 2 environment.
I see in 500.7(C) that dust tight enclosures are accepted as a protection technique. By not allowing dust in the enclosure is this area still considered class 2 div 2? are the components required to be class rated?
I have seen other postings online saying that you can use a NEMA 9 enclosure and use non class rated components but dont see this in the code. Can anyone point this out to me if this is so?
My current thoughts while approaching this is that i have an area that is Class 2 div 2. If i want to use parts that are not rated for this i need to create an environment that is unclassified. is this the best way of looking at it? This thought process has brought up my next question. When the door of the enclosure is open the area is Class 2 Div 2 do i need to supply an alarm or door switch to kill power to the panel when the door is open and if i go with a purging/pressurized system when the panel loses pressure? I probably need to browse through NFPA 496 more for answers to the pressurizing system but any direction you can give is much appreciated.
Thanks in Advance!