Article 514.9(B)

[hannibal1]

Will be installing conduit from natural gas dispensing pumps (which are class1 - div1 locations) to a 1600AMP 480V Main distribution board that is NEMA 3R and will sit outside in free air in an unclassified area. If I understand correctly at least 1 additional seal would be required when I come up from underground directly into the bottom of the MDP. Where can I put this seal where it will be accessable for inspection? Am I interpreting this correctly?
Hoping someone can shed some light before I visit with the UL inspector.

 

[rbalex]

This is a tough one because Art 514 technically shouldn?t apply to natural gas dispensers.

The Article is largely extracted from NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair Garages, which expressly states various natural gas fuels are not in its Scope. Table 514.3(B)(2) is a direct extraction from NFPA 30A Table 12.6.2 and reflects the properties of ?heavier than air? fuels. Natural gas is a ?lighter than air? fuel.

I don?t know the basis for the electrical area classification in the immediate area of the pump but I know that unless other fuels that are subject to NFPA 30A are also being used the second seal is useless.

Having said all that if a second seal is necessary it will most likely need to be at the switchgear stub-up.