What size circuit breaker for 240v 60hz garage heater?

The size of the circuit breaker for a 240V, 60Hz garage heater typically depends on the heater's wattage. A common rule of thumb is to choose a breaker rated at 125% of the heater's full load current. For example, if the heater is rated at 4,000 watts, the current draw would be approximately 16.7 amps, so a 20-amp circuit breaker would be appropriate. Always consult the manufacturer's specifications and local electrical codes for precise requirements.