Boundary Seals Between CL 1 Div 2 and Unclassified

[jscadman]

Forgive me if this has already been addressed, but I cannot find it by searching.

When installing a conduit seal between Div 1 and Div 2, and the conduit runs underground, the seal is permitted to be installed at the end that exits the ground if the boundary exists where the conduit is underground - 501.15(A)(4) Exception 2 I believe.

I'm not sure what to do if the same situation exists for Div 2 to unclassified. My thoughts are that if is good enough for Div 1 to Div 2, then it should be okay for Div 2 to unclassified, but the NEC does not specifically state this.

We have conduit entering the ground in a Div 2 area and installed underground for over 100' before exiting. The classification boundary exists a some point where the conduit is buried.

Thoughts?

 

[rbalex]

Forgive me if this has already been addressed, but I cannot find it by searching.

When installing a conduit seal between Div 1 and Div 2, and the conduit runs underground, the seal is permitted to be installed at the end that exits the ground if the boundary exists where the conduit is underground - 501.15(A)(4) Exception 2 I believe.

I'm not sure what to do if the same situation exists for Div 2 to unclassified. My thoughts are that if is good enough for Div 1 to Div 2, then it should be okay for Div 2 to unclassified, but the NEC does not specifically state this.

We have conduit entering the ground in a Div 2 area and installed underground for over 100' before exiting. The classification boundary exists a some point where the conduit is buried.

Thoughts?

Welcome to the forums.

Section 501.15(A)(4) Exception 2 was proposed by the API in the 2002 NEC to solve some issues created in Article 514. The problem has largely disappeared since the 2005 NEC.

The basic question is: "Why would a boundary exist underground in the first place?" The answer can be found by comparing Figure 514.3 in the 2002 NEC and earlier with the same Figure since 2005.

Typically, the underground is unclassified, so the "boundary" should always be at grade, never underground.

 

[jscadman]

Thanks For Your Explanation.

Thanks For Your Explanation.

Welcome to the forums.

Section 501.15(A)(4) Exception 2 was proposed by the API in the 2002 NEC to solve some issues created in Article 514. The problem has largely disappeared since the 2005 NEC.

The basic question is: "Why would a boundary exist underground in the first place?" The answer can be found by comparing Figure 514.3 in the 2002 NEC and earlier with the same Figure since 2005.

Typically, the underground is unclassified, so the "boundary" should always be at grade, never underground.

It appears that installing the seal on either side of the boundary is moot at this point as it must be installed in the classified area since the unclassified area (at least the first 10 feet past the boundary) is underground.

 

[rbalex]

It appears that installing the seal on either side of the boundary is moot at this point as it must be installed in the classified area since the unclassified area (at least the first 10 feet past the boundary) is underground.

It simplifies a lot.