To determine how many watts a branch circuit can handle, you need to know two things. First, you need to know how many amperes, or amps, for which a circuit is rated. An amp is the amount of electrical current that flows through a circuit. In most homes lighting and small appliance circuits are 15 or 20 amps, and major appliances are on 20, 50 or even 60 amp circuits.
Second, you need to know the volts flowing through the wires. Volts are a measure of the pressure that causes current to flow through a circuit. Generally, household wiring is 120 or 240 volts.
To determine the amount of wattage a branch circuit can handle, multiply the circuit's amperage by the circuit's volts. A 20-amp, 120-volt circuit can handle 2,400 watts.
The following list gives you the average wattage rating for common household equipment. For specific information on your home equipment, check the manufacturer's listing found in your owners manual or on the information plate of the equipment.
For lighting, check the wattage rating of the bulbs being used.
|Average Wattage Rating|
|Frost Free Deep Freeze||500|
|Frost Free Refrigerator||615|
|2 Burner Hot Plate||1,650|
|Range||4,000 - 5,000|
|Vacuum Cleaner||750 - 1,350|
|Water Heater||2,000 - 5,000|
|Standard Deep Freeze||400|
|Garbage Disposal||450 - 950|
|Oven||4,000 - 8,000|