Electrical 101

High Wattage Appliances

Appliances with high power consumption can use up most of the capacity of a 15 or 20 amp circuit. They could cause an overload when combined with other appliances and trip the circuit breaker.

If two hair dryers are used at the same time on the same circuit, the circuit breaker will trip. Outlets in two different bathrooms can be on the same circuit. Distributing high power appliances to a separate circuit, or not using them at the same time may help prevent tripping a circuit breaker.

Hair dryer
Electric space heater
Window air conditioner
Garbage compactor

Countertop microwave
Electric tea kettle
Toaster / toaster oven
Coffee maker

Dedicated Circuits

A dedicated circuit has only one outlet and is used for a load that has a high current rating. The list below shows common appliances that are usually (or should be) on a dedicated circuit. For more information see our dedicated circuits page.

Kitchen Appliance Wattage Ratings

Kitchen appliances should be arranged not to exceed the derated capacity of a circuit. Appliances have labels that show information including rated load in watts, amps, or volt-amps. The actual appliance load may be a bit smaller than the rated load, but the rated load should be used when calculating total appliance load on a circuit.

Add the wattage rating of each appliance on the same circuit, try not to exceed 1920 W on a 20 A circuit and 1440 watts on a 15 A circuit (ignore appliances on a dedicated circuit).

Circuit Breaker Trips Frequently

High Wattage Appliance Examples

Electric range and oven
Window air conditioner 1200 watts or more

Wall mounted microwave
Electric dryer

Maximum Watts on Circuits

Circuits should never exceed or carry their full load capacity except for very short times. Instead, they should be derated by a minimum of 20%. This prevents circuit breakers and wires from overheating.

The Derated Circuit Capacity Table shows the derated capacity of 20 and 15 amp circuits. Total appliance load should not exceed this derated capacity on a circuit.

Derated Circuit Capacity Table

Toaster Label

Not Enough Circuits for all Appliances

Sometimes the total wattage of appliances is higher than total circuit capacity, especially in smaller or older homes. In this case, arrange appliances that won’t normally be used at the same time on the same circuit. The countertop oven above right should not be on the same circuit as any other high wattage appliance unless they will not be used at the same time.

Built-in Microwave Label

Countertop Oven Label

1480 Watts on a dedicated circuit