Agreed, but there's more to it I think. The primary design goal of the system is don't accidentally start a fire or electrocute yourself. The other effect however is the inverse, a mechanism by which the power company can come up with the right distribution of transformers to get the power to your home. If you have not been wired by an electrician to handle that much electricity, your block may not be sufficiently wired and fused to deliver that much. Because presumably the electrician checks such things before putting buildings on the grid.