The size of the circuit breaker needed for a dryer depends on the wattage of the electric dryer. Most residential dryers require a 30-amp circuit breaker, according to the National Electrical Code. However, it is important to check the back of your dryer to see what size breaker you need, as some dryers may require a different size. The breaker size should match the wattage of the dryer to prevent electrical issues and ensure safe and efficient operation. If the wattage of your electric dryer is 240 volts, then it will require a 30-amp circuit breaker. However, if the wattage is more than 4,000 watts, then it will require a 40-amp circuit breaker. It is always important to consult a licensed electrician if you are unsure about your dryers electrical requirements or breaker size.