The US electrical code uses several different receptacles to ensure devices will only be plugged into a circuit that can sustain its power requirements. The lo

The US electrical code uses several different receptacles to ensure devices will only be plugged into a circuit that can sustain its power requirements. The lower voltage 120V commonly used in the US does necessitate a doubling of the number of receptacles needed (NEMA-5 vs NEMA-6), versus 230v countries which run all their appliances on a higher standard voltage in the first place. Then you have historical plugs that don't entirely go away like NEMA-1.