UG Feeder Into Classified Location

[steveve1]

On a large truck maintence faculity, the service entrance/distribution equipment is located in an un-classified location. One transformer and one 400a panel are located within the classified location boundries. These are each fed by underground raceways from the DP and are located on the wall that defines the division between the classified and un-classified areas. The classified location is governed under art. 511. The installation of the feeder conduit is as follows:

1) 90 dergee bends were made in full sticks of GRC so that no fitting is below 30" above the floor in the classified location.

2) 10' lengths of conduit were used, and the direction of the underground system led away from the above classified location, thus the transition to PVC conduit is some 5' beyond the wall seperating the two locations and under the un-classified area.

My take on this installation is that art. 501-5 (b)(2) Exception No. 1 applies and no seal-offs are required.

I'm currently "discussing" this issue with the AHJ, who seems to find a violation, and wants to see seal-off fittings.

Your input would be appreciated. Thanks

 

[charlie]

Re: UG Feeder Into Classified Location

I "feel" like the inspector is correct, I would put in the seals.

However, the inspector is technically incorrect. 511.4 is clear where is states, "if any connections or extensions lead into or through such areas." That is not the case and the seals are not required.

 

[rbalex]

Re: UG Feeder Into Classified Location

I am assuming that the facility will not be dispensing fuel. That could markedly change the analysis.

Near the transformer and panel the Division 2 location is delimited:
Lower limit ? the floor
Horizontal limit ? the wall the transformer and panel are mounted on
Upper limit ? 18? above the floor

The transformer and panel are both mounted more than 12? above the upper limit.
The conduit below the floor extends more than 12? beyond the boundary.

Assuming the panel is otherwise approved for the application under 511.7(B), this is exactly the application 501.5(B)(2) Ex 1 envisions. The transformer should be no problem.