Amperage is a measure of the flow of electricity from power lines into your home and to appliances that use electricity. At one time, most homes were wired for 60-amp electrical service, but today 100-amp service is standard for new homes.

Service Panels

Amperage is controlled at the service panel or main fuse box. The flow of electricity from outside power lines runs through the main breaker.

Maximum Amperage

Each circuit breaker controls electricity to a specific zone of the home. Breakers are set up so that a maximum of about 80 percent of the rated amperage can be in use.

Circuit Breakers

An appliance rated at 1,200 watts, divided by 120-volt electrical current, gives an amperage of 10. If this appliance is used on a circuit breaker rated at 15 amps, it should work fine. If it used in the same zone with another appliance rated at 15, the circuit breaker will overload and trip. You will have to reset the breaker.

Electric Bills

Your monthly electrical bill is a measure of the number of watts you have used, which is figured by metering the amperage in use and multiplying it by your voltage rating. Most utility companies charge by the kilowatt-hour (KwH), which is 1,000 watts in use for one hour.

Use

The more appliances you use, the more amperage you use. Larger appliances such as dryers and window air conditioners generally pull more amps than smaller devices such as notebook computers and lamps.

Source:

WiseGeek.com: What is Amperage?

NDT Resource Center: Amperage