KentAT
Senior Member
- Location
- Northeastern PA
I had an installation on a prefab building that I modified, although it appeared to be a gray area.
We have a Class 1, Div 1 room housing hi-pressure natural gas metering equipment at a facility that feeds the local gas company. Other side of the wall is Div 2. There is a 12"x12"x6" Ex-P JB mounted on the inside wall (Div 1), and contains relays serving solenoids on the outside of the wall, in the Div 2 area. The mfg of the room (prefab) ran the 3/4" conduit out the side of the JB, with a union, then to an LBY, then a short nipple through the 3" thick precast concrete wall that the box is mounted on, to a GUA box w/ a GUA sealing cover just on the outside of the wall. This was the boundary seal. (All fittings were listed for haz. locs.)
I wanted a seal in the Div 1 area for the enclosure, but I think the mfg intended for the GUA on the outside to serve as the seal for the boundary and for the inside enclosure, since it was technically within 18" (of conduit measurement) of the enclosure.
Can the original GUA serve as the required seal within 18" of the enclosure in the Div 1 area, although it was located on the Div 2 side of the boundary?
I can accept the fact that even if I had a seal on the inside instead, there will be the same amount of exposed threaded connections, etc in 10" or so of conduit/fittings in the Div 1 area so there really is no increased risk one way or the other, but I preferred to have the enclosure seal in the same rated area as the enclosure that is requiring the seal to begin with.
Am I splitting hairs, or what?
We have a Class 1, Div 1 room housing hi-pressure natural gas metering equipment at a facility that feeds the local gas company. Other side of the wall is Div 2. There is a 12"x12"x6" Ex-P JB mounted on the inside wall (Div 1), and contains relays serving solenoids on the outside of the wall, in the Div 2 area. The mfg of the room (prefab) ran the 3/4" conduit out the side of the JB, with a union, then to an LBY, then a short nipple through the 3" thick precast concrete wall that the box is mounted on, to a GUA box w/ a GUA sealing cover just on the outside of the wall. This was the boundary seal. (All fittings were listed for haz. locs.)
I wanted a seal in the Div 1 area for the enclosure, but I think the mfg intended for the GUA on the outside to serve as the seal for the boundary and for the inside enclosure, since it was technically within 18" (of conduit measurement) of the enclosure.
Can the original GUA serve as the required seal within 18" of the enclosure in the Div 1 area, although it was located on the Div 2 side of the boundary?
I can accept the fact that even if I had a seal on the inside instead, there will be the same amount of exposed threaded connections, etc in 10" or so of conduit/fittings in the Div 1 area so there really is no increased risk one way or the other, but I preferred to have the enclosure seal in the same rated area as the enclosure that is requiring the seal to begin with.
Am I splitting hairs, or what?
