I'm wiring an above ground, outdoor gasoline storage tank with a dispensing pump on it. The tank is surrounded by a chain link fence. I was going to run 1/2" IMC about 20' from the J box to the fence and up a mast to a weatherhead for an overhead feed.

Do I need any sealoffs in this run? Where would they be located?

thanks

I strongly suggest that you contact your local AHJ, with your plan in sketch form.

The J box in the pump?? If so, yes would be my answer. Conduit going underground? if so last fitting before it enters the ground at pump and first fitting after it exits the ground at fence

Pump mounted on top of the tank, 5' horizontally over to fence, turn 90D then another 5' to corner post/mast, turn 90D up and go 8' to weatherhead.

Feed is overhead.