Electricity is brought to your house by high-voltage wires carried on utility poles. Just outside your home, these high-voltage wires enter a transformer, which reduces the voltage to the 120 volts necessary to power home electronics. From the transformer, the lower-voltage electricity the flows into the meter, which monitors the amount of electricity that you use and sends the electricity inside.
Once through the meter, power now enters your home electrical system. It begins at the circuit breaker panel. In most homes, this can be found in the basement, garage, or somewhere out of the way. The circuit breaker panel is the nerve center of your home: it controls the flow and distribution of electricity into every room.
Your home electrical system typically enters the circuit breaker panel through three wires, two of which are hot, and one of which is a neutral ground wire. Each of the hot wires runs through the main shutoff switch and down the bus bars, which span the length of the panel. Individual circuits branch off of these bars, beginning with a circuit breaker.
Electricity flows in a circuit: it moves out of the circuit breaker panel, into a room in your house, out of (for example) an outlet, into an appliance, and then it flows back out of the appliance, following the same path back the circuit breaker panel. If this circuit is interrupted at any point, the electricity stops flowing. Circuit breakers are so called because they are designed to break the circuit of electricity in an emergency or to do work on your home electrical system. They will break the circuit automatically if it becomes overloaded.
Once it leaves the circuit breaker panel, electricity is carried through electrical wiring. Typically, it leaves the circuit box in a black wire, and is returned to it in a white wire. There will also be a ground wire, which carries electricity in the event of an overload to the neutral white wire in the circuit breaker panel, where it is discharged harmlessly into the earth.
Each circuit will supply electricity to several outlets and switches in your home, although larger appliances like washing machines and refrigerators may have their own dedicated circuit. Circuits are usually organized by room, both for efficiency in wiring and to make the circuit breaker that corresponds to a particular outlet or switch easy to identify on the panel.
Behind the walls, electricity is carried by insulated copper wires. The bigger the wire, the higher the current it will be able to carry. Wires will overeat if they carry a higher current than they’re rated for, which is why a proper circuit breaker is so important.
Electricity is dispersed to everyday appliances by switches and power outlets. Switches affect the flow of your electricity most typically by either breaking or completing the circuit. Switches called dimmers also control the amount of electricity flowing through the circuit. The standard outlet has contact points inside that complete the circuit when they touch the plugs of electronic devices. Today, one side of the outlet will be wider than the other, which is a safety measure to ensure that electricity stops flowing through a device when it’s turned off.
Although electricity is obviously an important utility found in most homes, it can also prove to be dangerous when tampered with by those of us who don’t know what we’re doing. So, if you’re planning on starting any major projects in your home or office that require electrical work, it might be worth your while contacting your local certified electrician to seek advice.