Electric Hot Water Heater Amp Draw
The amperage on such a tank is i w e.
Electric hot water heater amp draw. 120 volt elements consume 1125 watts while residential 240 volt heaters use 4 500 watts. The amperage of a water heater is governed by the wattage of the heating elements and the voltage that is applied to them. Unfortunately the average electric tankless water heater needs at least 120 amps to operate and the average household s total capacity is 200 amps. In a us household the current draw for a 1500 watt water heater is 12 5 amps.
Now in order to choose an electric breaker multiply the current draw of the water heater with 125 per cent in order to determine the size of the breaker you will need. You have stated that the calculated amperage load for 4500watt at 240volts is 18 75amps however nec article 422 13 states that the minimum circuit rating for a water heater must be 125 of the rated load so this 4500watt load requires a minimum circuit of 23 44 amps at 240volts. Water heaters running on 120 volt power have a long recovery time which is impractical for most households. What is average size of a hot water heater.
A 200 amp service allows operation of multiple appliances at once while a 60 amp service won t provide enough power to run an electric hot water heater air conditioner and hair dryer simultaneously. This means you will have to upgrade your electrical system to accommodate for the larger load demand which could cost you up to 1 500. Multiply the current rating of the water heater with 125. A 20 amp breaker would still be large enough.