Since this is a purely resistive load 5500 watts at 240 volts is 23 amps, breaker is sized at 30 amps and 10 awg wiring is used. In your case if the elements are strapped for 4500 watts draw is 18.75 amps, permanent draw loads should be sized at 80% of breaker capacity so a 20 amp breaker is limited to 16 amps.read more >>