Why doesn’t that blow fuses? I presume that it's because the electrical conductance of the petrol is too low. As a supplementary question, the pump motor potentially produces sparks (if of a certain type) isn’t that a problem in a fuel tank? A couple of guesses. Because there isn't enough oxygen to ignite the fuel? Or because there isn't a spark if whatever causes it in air doesn't happen in petrol. I prefer the first as we don't hear about ignition when fuel pumps are run in tanks containing very little liquid petrol. Jonathan PS: Inflammable oil is commonly used in transformers etc as a coolant. And IIRC the petrol does cool the pump in ordinary cars. PPS: Ordinary bullets don't cause car fuel tanks to explode, pace Hollywood (Mythbusters episode 15). And just checking cigarette butts flicked in to the filler...