I have a customer w/a outdoor diesel tank which has a pump. (purpose to fill trucks)
It is not a pump like a gas station. Just a big cylindrical tank with a pump motor.
Need to run 115 cir from adjacent building.
All conduit to be surface mounted on interior wall, through to outside and pump location. Question is is this a Class 1 Div 1 area? diesel is not a gas, but has a flashpoint of 160F to 180F. I am mounting a disconnect w/in eysight of the pump behind the tank (about 12') Does it have to be explosion proof? Are EYS seals required. Customer wants keyswitch to turn on pump when filling. Assume I need EYS fitting there too. (never done explosion proof before). Will conduit in building have to be rigid? Would like to run EMT in building out to disconnect than rigid to pump. Acceptable??
Do not see "diesel" mentioned in 500 section of NEC.
Called inspection agency and they said treat diesel same as gas.

I don't believe that a diesal fuel dispenser is a hazardous location that would require seals, threaded pipe etc.

Take a look at 514.3(A)

Tom

It seems to me a tank outside cannot be a Class I area.

ayrton,
Lots of outside areas are Class 1 locations. Some are even Class 1 Division 1.
Don

I still cannot determine from 500 sec of NEC whether or not this falls under a classified area. Is it up to me to determine or an engineer?

Diesel has a flashpoint of 160 deg F to 180 deg F. According to International fire Code Flammable liquid is anything under 100 deg F. So that tells me it is not a "flammable liquid", so it doesnt fall into a classification in Sec 500- of the NEC

Diesel fuel does not fall into article 500.

Not classified.

Seal Tite would be what I have used many times on Diesel, Kero, or 2 oil. Unless gasoline is on the same island.

I have the same situation here, and this is what I found...read on...

Diesel fuel is considered combustible, not flammable. Therefore, a diesel dispensing area is unclassified, and associated electrical equipment and wiring need not comply with the requirements of Chapter 5. But it's common to wire diesel fuel dispensers adjacent to gasoline dispensers. If conduit for the diesel dispenser passes through the Class I, Div. 1 or 2 areas around the gasoline dispenser, the wiring methods and sealing requirements in Art. 501 apply.
I found this at http://ecmweb.com/conference/holt/electric_preventing_fires_gas/

Hopes this helps.