These outlets are the ones you’re most likely have in your house.
Ok, so lets talk about the types of outlets you’ll find in your house. For the most part you are going to see 120 volts, 15 amp and 20 amp. And 220 2 wire, 3 wire and four wire types.
Please remember not all 220 volt outlets use a neutral (white) wire. To give you a general idea, lets say you just bought a air compressor from Home Depot. It requires 220 volt but the plug only has three prongs. You’ll have the two that look a like will be the two separate hot’s and other round looking on would be the ground. And of course more than likely it would be 20 amp.