Instead you need at least 25 amp.
Breaker size for electric hot water heater.
1 or 2.
Choose the right tankless electric water heater for you.
Wire a hot water heater with wire that s sized to accommodate the heater s current requirement.
I agree with you that this water heater circuit is not a typical configuration and the common circuit for a new home is 10 copper wire protected by a 2pole 30amp circuit breaker however lets look at this application carefully.
Multiply the current rating of the water heater with 125.
You can estimate the necessary tank capacity in gallons based on the number of people in the house.
Rheem tankless electric water heaters make it easy to enjoy instantaneous continuous hot water space saving design and significant energy cost savings.
This happens because 20 amp from the water heater is more than 80 of the breaker capacity.
So it won t work as effectively as it needs.
Thus the current draw for a 1 500 watt heater is 12 5 amps.
Electric water heaters require a 240 volt dedicated circuit which serves only the water heater and no other appliances or devices.
Just follow the three simple steps below to choose the right model and size you need.
In the above example we would require a 15 6 amp circuit breaker for our us readers.
Multiply the value for current by 125.
But with a 25 amp breaker the 20 amp water heater will only cover 80 of the total capacity of the circuit breaker.
For a tank style heater household size is a simple indicator of hot water needs.
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.
So it will work consistently and in a stable way.
The circuit wiring typically includes a 30 amp double pole breaker and 10 2 non metallic nm or mc cable.
Some large heaters draw up to 50 amps requiring 6 gauge wire.