This is rather interesting with all you US people saying that the Positive is always the Pole Grounded, here it would be the Negative,
people have been arguing about this since electricity was discovered, as in which way does the current flow?.
There is Conventional Current Flow(+ve to -ve) and there is Electron Current Flow (-ve to +ve), the US being (obviously) different to anything the English did, took on Conventional current flow ideas, that is why most cars in the US have a positive ground in them, while the rest of the world is negative ground.