Understanding Household Electric Terms: Volts, Amps, and Watts

There are three terms that are often used when the subject of electricity comes up: ampere, volt, and watt. Each of these terms is used to described a very specific amount of electric power. Knowing what an ampere, volt, and watt are and how they relate to your electric usage can help you understand electric power requirements for new appliances, read your electric bill, and prevent overloading a fuse or circuit.

Electricity flowing through a wire is similar to water flowing through a hose. If the water hose were rigged to turn a water wheel, and the faucet was just slightly open, the wheel would turn slowly. When the faucet is fully open, water rushes out quickly turning the wheel faster. The more the faucet is opened, the greater the water pressure in the hose and the greater flow. Electricity also operates in this same way.

Greater pressure in the wires (volts) causes an increase in the flow of electricity (amps) and this results in more work (watts). There is one more related term: watt-hour.The watt-hour is a measurement of the amount of work done over time. This is the measurement used by the electric companies to determine the amount of electricity used in the home. The term that appears on the bill is kwh, which stands for kilo-watt hour, or 1,000 watt hours.

The electricity that powers the home comes in through two power lines of 120 volts each. A third line (neutral) also comes into the house from the pole. All three enter the meter box and from there they are installed in the home electrical panel. Then the power is distributed in usable amounts through circuits in various areas of the house.

Circuits are made up of wires that supply power to lights, receptacles, and appliances. The many circuits in a home electrical system include several 15-amp lighting circuits, at least two 20-amp small appliance circuits, and several single-appliance circuits that supply power to major appliances like refrigerators, electric ranges, washing machines and dryers, and air conditioning units.

Homes have either a main fuse panel or a circuit breaker panel. The difference is with a fuse panel, the fuses are screwed into a socket. When a fuse is subjected to a load that surpasses its rated capacity, it "blows", creating a disconnect in the circuit. The fuse must then be replaced and the overload corrected. With circuit breakers, under the same conditions, the switch on the breaker is "reset", and the current in the circuit becomes instantly active again.

Switches that are located in the home interrupt the flow of electricity within its assigned circuit. Plug-in receptacles are "live" all the time unless controlled by a switch. These outlets are generally assigned to a 20-amp fuse or breaker and there are often two or three that are operated on a single circuit.

Become familiar with the electrical system in your home. Know the location of the electrical panel and the type of circuit protection is in use.

Always work safely with electricity.