What Size Breaker Do I Need for My Microwave?

With an average lifetime of nine years, microwaves are more prone to replacement than larger appliance such as gas stoves or refrigerators. Because microwaves require lots of power, they sometimes fall victim to overloading and overheating. Installing a properly sized circuit breaker on your service panel will help prevent damage to your microwave and other appliances during electrical system failures.

Woman microwaving bottle
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Installing a circuit breaker reduces the chance of microwaves overheating during power surges.

Function

The main purpose of circuit breakers is to break or "trip" the electrical current traveling between your home's service panel and the actual circuit or outlet connected to your appliance. Shutting off the power to the circuit during power surges prevents wires from overheating and permanently damaging sensitive appliances such as microwaves. When circuits overload, permanent metal strips inside the breakers bend and trigger a tripping mechanism. The trip flips the switch and cuts power flowing to the circuit.

Voltage

According to the Electrical Safety Foundational International. breakers are sized for handling either 120-volt circuits or 240-volt circuits, depending on the appliance. Because120-volt circuits are used for small appliances, they are also appropriate for microwaves. The voltage refers to the amount of pressure pushing the electrical current through the circuit.

Amperage

Additionally, check your microwave's amperage, which is the microwave's wattage divided by the circuit's voltage. Amperage is the actual amount of electrical current running through the circuit. Typical wattage for microwave ovens ranges between 750 and 1,100, according to the U.S. Department of Energy. Though utility companies such as Georgia Power estimate that amperage for most small appliances falls between 15 and 20, some microwaves have an amp rating as low as 10.

Installation

Circuit breakers work in conjunction with the microwave's electrical outlet, as well as the wiring leading to the outlet. Ensure that both the outlet and circuit breaker can handle the same amperage. Otherwise, the breaker can trip prematurely. Also, installing an outlet with a lower amperage rating than the circuit breaker can interrupt the breaker's tripping mechanism when the maximum rated current is exceeded. Some manufacturers also recommend installing a separate circuit for built-in microwave wall units to avoid repeated tripping.

Considerations

To avoid circuit tripping, install a breaker that accepts a current slightly higher than the microwave's listed amperage. If your microwave oven has a 14.7 electrical current requirement, buy a 20-amp breaker to prevent breaker-tripping. Purchasing a breaker with a slightly higher amperage rating gives the appliance some room for margin of error. Older breakers also tend to trip more easily.