For hardwired versions: FLO Home X3 hardwired versions are factory set to 48 amps as it accommodates most installations more easily. A 60 amp circuit breaker is required for this installation. However, to take advantage of the full 50 amps, an electrician can adjust the amperage up and will need to use a circuit rated for 70 amps. For NEMA 14-50 plug-in versions: You will need a circuit rated for 50 amps, which will give you the output of 40 amps.