What size breaker would you need for 15 ton R.T.U?

To determine the appropriate breaker size for a 15-ton rooftop unit (R.T.U.), you typically use a rule of thumb that suggests sizing the breaker based on the unit's full load amperage (FLA). A 15-ton unit generally has an FLA of around 60-75 amps, depending on its specific efficiency ratings and electrical specifications. Therefore, a breaker size of 80 amps is commonly recommended to accommodate starting currents and ensure proper protection. Always consult the manufacturer's specifications and local electrical codes for precise sizing.