[BigLew]

The the issue here is the fire/explosion potential during fueling. If there's a voltage potential between the gas nozzle and the filler pipe there is a potential for spark. Because the tank filler hose is rubber and thus nine conductive, it is better to electrically link the filler pipe to the fueltank. Generally, it is done with a green colored insulated wire coil wrapped around the fuel hose and connected to both the filler pipe in fueltank. The fueling nozzle should be touched to the filler pipe before removing the threaded fuelpipe cover, thus dissipating any electrical potential, i.e. spark.