I was plugging in my iPhone charger to a surge protector; I was pushing it in, as it didn't go in easily, the surge popped and started smoking, of course tripping the breaker. The charger block has black smears on it, as well as on one of the prongs that goes into the outlet. The USB was also connected during the incident, but it does not show any signs of damage. It appears the charger is no longer able to be used; I'm afraid to even try. But my question is, is the USB still usable? Would it damage another charger or my computer if I tried to plug it into that?