They are organized as a continuous loop of two-core-and-earth wire that goes through the walls from the consumer unit, all the way around the house's footprint, and returns to the same terminal in the consumer unit. The other end of this circuit loop is connected to the opposite terminal on the other side of the meter.
The two cores of the wiring system represent a hot line and a neutral line. The entire circuit is called a "hot wire", since both lines are always live with respect to ground.
The typical household has several outlets for various appliances. These include a lamp, a refrigerator, a microwave, a dishwasher, and any other device that uses electricity but doesn't need to be on all the time. Each of these appliances has its own breaker which shuts off power to that section of the house when it is turned off. For example, if you flip the switch for your refrigerator, it will shut off power to everything else in the kitchen while the refrigerator runs. When you're finished using the refrigerator you have to restart it by turning it back on. There is no way to stop it from running all day long like a light bulb! The same thing applies to all your other appliances. Anytime you turn off the power, you're done using that feature for that cycle of the program; then you have to manually start it up again later.
The cable leaves the consumer unit and runs to each outlet position before terminating at the last fitting on the line. Most houses have at least two lighting circuits, usually one upstairs and one downstairs. For your safety, electrical products must be installed in accordance with local building regulations. Check with an electrician if you have any doubts about how to proceed.
A ring circuit connects all of the electricity outlets in a residence. The live, neutral, and earth wires of a ring circuit form a cable loop that runs from the consumer unit to each socket in turn, and then back to the consumer unit. The live wire delivers high-voltage current to the house/appliance. The hot wire carries current when the appliance is on but not plugged in. The neutral wire is supposed to be dead (zero voltage) when the appliance is off or unplugged. The third wire serves as a ground for the ring main, which means that it should have no voltage on it anywhere in the house.
The ring main enters the house through the breaker box, where it divides into individual branches to reach each outlet. These branches include the supply line, which goes to the street meter; the return line, which returns back to the breaker panel; and one branch for each outlet.
The supply line cannot connect directly to any outlet but must first go through the breaker panel. This is because power companies place safety switches inside most homes that shut off the power immediately if something interrupts the line voltage. If these breaks were not there, someone might receive a shock if an animal bit the line or a person bumped a cord while trying to move a refrigerator or air conditioner.
The return line comes directly out of the wall and back into the breaker panel.