48. •• A 5.5-kW water heater operates at 240 V.

(a) Should the heater circuit have a 20-A or a 30-A circuit breaker?

(A circuit breaker is a safety device that “opens” the circuit – shutting down the current – at its rated current.)

(b) Assuming 85% efficiency, how long will the heater take to heat the water in a 55-gal tank from 20 °C to 80 °C?