7/10/2016
High Wattage Appliances ­ Electrical 101
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High Wattage Appliances
Electrical
Troubleshoot
ing
Electrical
Meters and
Testers
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. Receptacles 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.
High Wattage Appliance Examples
Battery
Testers
Hair dryer
Countertop microwave
Electric space heater
Electric tea kettle
Input
Impedance
Window air conditioner
Toaster / toaster oven
Garbage compactor
Coffee maker
High Wattage
Appliances
Circuit
Breakers
Test and
Troubleshoot
Outlets
Test and
Troubleshoot
GFCIs
Troubleshoot
Lights
Troubleshoot
Switches
Troubleshoot
3­way
Switches
Troubleshoot
4­way
Switches
Open Neutral
Dedicated Circuits
A dedicated circuit has only one receptacle 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.
Electric range and oven
Wall mounted microwave
Window air conditioner 1200 watts or more
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.
Derated Circuit Capacity Table
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.
Kitchen Appliance Arrangement
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 volt­amps. 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).
Toaster Label
Built­in Microwave Label
Countertop Oven Label
Open Neutral
Multi­wire
Circuit
No Power to
Outlets
Troubleshoot
Garage Door
Opener
1480 Watts on a dedicated
circuit
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.
Circuit Breaker Trips Frequently
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