Propane Filling Station

[mister223]

Hi guys a Hardware store I work for had a propane filling tank installed and needs it wired. There is a 20 amp post mounted receptacle about 30 feet away. The gas companies electrician and gas technician told the owner that the post power would be adequate. It is a GFCI mounted in a Arlington PVC post. It is on it's own 20 amp circuit. How could I make this comply with code? Thanks