A 1500 watt heater on a 120 volt circuit thus needs a breaker of 15 6 amps.
What size circuit breaker do i need for a hot water heater.
Electric water heaters require a 240 volt dedicated circuit which serves only the water heater and no other appliances or devices.
Which size of water heater breaker to go for.
Understanding water heater wiring.
If you need additional space in the panel for the circuit breaker then a quad circuit breaker may be allowed as specified by the make and model of the panel.
A tankless water heater will require a dedicated circuit as specified by the installation manual of the unit that has been selected.
The general rule of thumb is that circuit breaker size should be 125 of the ampacity of cable and wire or the circuit which has to be protected by the cb.
Multiply the value for current by 125 percent to determine the size of the breaker you need for the heater.
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.
The circuit wiring typically includes a 30 amp double pole breaker and 10 2 non metallic nm or mc cable.
To determine the appropriate size of circuit breaker for single phase supply it depends on multiple factors like type of load cable material and environment temperature etc.
Because it will use 25 amp in total getting a 30 amp breaker will cover it safely but a 35 amp unit will cover more than just a heater if needed.
You would need a circuit breaker that can handle 20 amps.
First lets start with the nec code for this water heater application 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.
This voltage in homes requires a double circuit breaker rated for the amperage draw of the hot water heaters.
Add up all the amps.
Let s say you need a total of 20 amps to run a certain area of the house.
This would be the perfect way to get a circuit breaker for your water heater.
In this case you need no less than 35 amp.
Voltage requirements most electric hot water heaters operate on 220 to 250 volts ac.