Once you take the fear of the unknown out of it, working with your home’s electricity isn’t that scary. Of course, you should treat it with respect and know when to call on a professional. But you should be able to deal with simple jobs, such as adding a new outlet or installing a new fixture, with little problem.
For electricity to run an appliance or light, we need at least 2 wires. The hot wire (black in a standard 2-wire cable) carries the electricity to the outlet or appliance. Until something is switched on, the electricity is dormant, waiting to be called into action. When you switch on a light or turn on your dishwasher, you complete a circuit, allowing the electricity to flow into the electrical device, and back out through the white neutral wire.
(A note of caution. While black is usually hot and white neutral, this may change depending on how a circuit has been wired. You can determine which wires are hot by using a simple circuit tester. Touch one end to the wire and the other to a ground, such as the outlet box or even the screw. If the little light comes on, the wire’s hot.)
Back in the old days, that’s all there was. Now, a standard 2-wire cable also contains a 3rd wire (makes sense, doesn’t it?) called the ground. This bare wire is basically a backup. In case of a fault anywhere in the circuit, such as a hot wire coming loose, it provides a quick return for the electricity to “ground”, literally, the earth. This sudden surge should blow the circuit breaker, and prevent such scenarios as a hot wire sparking continuously.
Now that you know the very basics of wiring, let’s replace an outlet next time.