Quick Answer
A microwave typically draws around 10-20 amps when starting, with some models peaking at 30 amps or more. This high inrush current is due to the magnetron's high-power startup requirement. It's essential to account for this surge when sizing a generator or electrical system.
Understanding Microwave Starting Current
When a microwave starts, it requires a high amount of electrical power to energize the magnetron, which is responsible for producing the high-frequency microwave energy. This high-power startup phase is a critical consideration when sizing a generator or electrical system for a microwave. A typical household microwave can draw up to 10 amps during normal operation, but when starting, it can surge to 20 amps or more.
Calculating Surge Current
To calculate the surge current for a specific microwave model, check the device’s nameplate or manufacturer’s documentation for the maximum startup current. This value can range from 10 to 30 amps or more, depending on the microwave’s power rating and design. For example, a 1200-watt microwave might require 20 amps to start, while a 1200-watt model from a different manufacturer might require 25 amps.
Generator Sizing Considerations
When sizing a generator for a microwave, it’s essential to consider the surge current requirement in addition to the device’s normal operating current. A general rule of thumb is to add 20-50% to the device’s maximum power rating to account for the surge current. This ensures that the generator can handle the high power demands of the microwave during startup. For example, a 2000-watt generator might be sufficient to power a 1200-watt microwave, but a 2500-watt generator would be a safer choice to account for the surge current.
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