When it comes to wiring, the most important consideration is to use the proper gauge. Wiring comes in different sizes depending on the circuit amp requirements and number of wires, or conductors. So, if you have a wire in your home that feeds a standard electrical outlet, it will have two conductors… the black wire which is the hot leg, and the white wire which is the neutral leg. It will also have a ground wire but this is not considered a conductor so is not used to label the wire.
Depending on how much current flows through the wire, it will be rated by size and the electrical industry uses a set of numbers to indicate this size like, #8 gauge or #12 gauge. They combine the wire size with the number of conductors and name the wire like that. So, a typical circuit might have a wire labeled, 10-2.
This means it is 10 gauge and has 2 conductors. It is absolutely vital to choose the right size wire for the amp draw of a circuit or appliance. If you are replacing the power cord for an appliance that is rated at 10 amps, would you know what size wire to use?
I can never remember if black goes to the copper screw and white goes to the silver screw or vice-versa…