Water Heater Circuit Size

A typical electric water heater requires a 30 amp 240 volt circuit this circuit is generally provided by installing a 10 2 nm with ground cable to the location of the water heater.

Water heater circuit size. 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. So if you have a heater using 6 000 watts in total in a 240 volt connection the operative ampere total would be 25 amp. To make your final choice we recommend getting a circuit breaker that offers at least twice the amount of amperage that your water heater will need.

If you can plug the heater into a regular wall outlet the specified voltage should be 120 volts. Electric water heaters require a 240 volt dedicated circuit which serves only the water heater and no other appliances or devices. If the location of the water heater requires a disconnect then a 240 volt 30 amp rated switch or disconnect should be installed at the water heater location. Wire a hot water heater with wire that s sized to accommodate the heater s current requirement.

Multiply the value for current by 125. Thus the current draw for a 1 500 watt heater is 12 5 amps. Hardwiring a water heater. In this case you need no less than 35 amp.

The circuit wiring typically includes a 30 amp double pole breaker and 10 2 non metallic nm or mc cable. 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. For example a 20 amp hot water heater needs 12 gauge wire a 25 amp hot water heater requires 10 gauge wire and a 30 to 40 amp hot water heater requires 8 gauge wire. Now lets consider this water heater circuit installation.

Just follow the three simple steps below to choose the right model and size you need. Some large heaters draw up to 50 amps requiring 6 gauge wire.