In terms of running a present day home, the Electrical System is probably second only to indoor Plumbing in importance. Without electricity we would still be using blocks of ice to power our refrigerators, and candles to light our rooms at night. And then there are the various gadgets that are virtually dead without access to electricity.
In most homes, electricity enters the house via an Electrical Service Panel that is hooked up to an electrical grid. However, there are also a number of homes that are effectively off the grid via solar panels as well. Either way, there is a central point at which electricity enters the rest of the home. From there, it is transported throughout the house via insulated wires. As a safety measure, the wiring is broken up into several sections known as circuits. In addition, these circuits will all run through a central panel capable of interrupting the circuit in the event that the power load exceeds the capacity of the circuit to handle. In older systems, the central panel uses fuses that burnout in the event of a circuit overload, and is often referred to as the Fuse Box. Newer systems use switches that can be tripped back and forth.
The wiring then conducts the electricity to a variety of sockets that can then be used by the homeowner to plug or screw things into, as well as switches that are used to control the flow of electricity to light fixtures.