Each charging level has its own plug design to prevent damage when charging. IIRC, the 500e uses a max of 6.6 kW, the same rate as the 2013 Leaf. If you plugged it into a CCS, I assume nothing would happen, since CCS isn't receiving a response signal. If it did start charging, would 40 to 90 kW (200V to 450V) make the batteries burst into flames or just fry the components? 6.6 kW sounds really slow today, but at its release it was a reliable standard. As a CA and OR compliance car, early articles said they made that choice for reliability and compatibility.