What Size Circuit Breaker Do I Need For A Hot Water Heater

The circuit wiring typically includes a 30 amp double pole breaker and 10 2 non metallic nm or mc cable.

What size circuit breaker do i need for a hot water heater.

Add up all the amps. Understanding water heater wiring. Electric water heaters require a 240 volt dedicated circuit which serves only the water heater and no other appliances or devices. 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.

In the above example we would require a 15 6 amp circuit breaker for our us readers. At the water heater the black circuit wire connects to the black wire lead on the water heater and the white circuit wire connects to the white wire lead on the water heater. Voltage requirements most electric hot water heaters operate on 220 to 250 volts ac. 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.

Multiply the value for current by 125 percent to determine the size of the breaker you need for the heater. You would need a circuit breaker that can handle 20 amps. 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. In this case you need no less than 35 amp.

This voltage in homes requires a double circuit breaker rated for the amperage draw of the hot water heaters. This would be the perfect way to get a circuit breaker for your water heater. 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. Multiply the current rating of the water heater with 125.

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. A tankless water heater will require a dedicated circuit as specified by the installation manual of the unit that has been selected. 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.