Class I, Division 1, Group D & Class II, Division 1, Groups E, F, G Junction boxes.

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Class I, Division 1, Group D & Class II, Division 1, Groups E, F, G Junction boxes.

I am designing a system that is in a Class I, Division 1, Group D & Class II, Division 1, Groups E, F & G hazardous location.

My main panel is x-purged and all the inputs on the machine are intrinsically safe and wiring to isolation barriers in the main panel.

My outputs (hydraulic and pneumatic solenoid valves) are explosion proof with an 18" potted cable coming off of the coil.

My potted cable is not long enough to go all the way to the main panel, can I use a standard NEMA 4 junction box with terminals snf seal-offs entering and exiting the junction box to the main panel? Or, do I need to use an explosion proof junction box as my termination point for the valves?

Thanks, Dan
 

Jim1959

Senior Member
Location
Longmont, CO
CID1 J-BOXES

CID1 J-BOXES

You would need to use J-boxes that are rated CID1 Per NEC 501.10.A.3

I would use Appleton GR series with terminal kits.

Nema 4 boxes are not rated CID1. The only seal offs you should need would be at the purged panel from the info you shared.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
If this were an animal you were describing, I'd call it a chimera. If all the inputs are truly intrinsically safe (IS) then you don't need a purged panel or explosionproof equipment in the field. See Sections 504.10(C) and 504.20. Do you have a control drawing from the manufacture of the barriers? In fact, you have read Article 504 and ANSI/ISA RP-12.06 very carefully, right? Note Articles 501 (Class I) and 502 (Class II) don't mention IS Systems at all.

Your purged panel needs to be per NFPA 496, Type X. That can be a nightmare and it's own right. Technically, if the panel is installed properly, it may not need to be sealed if the maintained pressure is proper. It's still isn't a bad idea to seal it To maintain pressure.

Also explosionproof equipment can be problematic in Class II. See Section 502.2.

If it turns out the solenoids and field wiring actually need to be suitable for Class I, Division 1 and Class II, Division 1, because it isn't an IS installation, then Jim1959's advice is fine.

I don't mind helping you interpret the relevant standards but I do mind doing your engineering for you. You are placing yourself in a DIY position.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I am designing a system that is in a Class I, Division 1, Group D & Class II, Division 1, Groups E, F & G hazardous location.

My main panel is x-purged and all the inputs on the machine are intrinsically safe and wiring to isolation barriers in the main panel.

My outputs (hydraulic and pneumatic solenoid valves) are explosion proof with an 18" potted cable coming off of the coil.

My potted cable is not long enough to go all the way to the main panel, can I use a standard NEMA 4 junction box with terminals snf seal-offs entering and exiting the junction box to the main panel? Or, do I need to use an explosion proof junction box as my termination point for the valves?

Thanks, Dan

If I am understanding your situation, you want to make the solenoid valve wires longer. You can do that by adding a junction box. If the junction box is in a Class I, Division 1 area, it would need to be XP. If by some miracle you managed to be able to reach a Division 2 area with your 18" leads, the junction box would not need to be XP.

However, chances are you won't get that lucky and will need some kind of XP junction box. Killark and others make small XP junction boxes just for this purpose.

https://www.automationdirect.com/ad...tion_Control_Stations/Device_-z-_Splice_Boxes

The problem you may have is getting something that is simultaneously suitable for both Class I and Class II.

I am not really up on Class II, Division 1 all that much but I don't think XP is where it is at there.

Is there anyway you can move the valves to a division 2 area, or unclassified area?
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
...
The problem you may have is getting something that is simultaneously suitable for both Class I and Class II.
...
The Appleton conduit bodies (Crouse-Hinds and several others make them too) Jim 1959 suggested and the boxes you suggested are suitable in both Class I and II.
 
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