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Electrical Circuit Considerations For Water Heaters

I am replacing an electric water heater. The original is 240 volts. Can I install a 120 volts…

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Dedicated Circuit Requirements for Electric Water Heaters
Background: Lonnie, a Homeowner from Oxnard, CA
[ad#block]Question: I am replacing an electric water heater. The original is 240 volts. Can I install a 120 volts? What changes do I need to do? All help is appreciated.


Dave’s Reply:
Thanks for your electrical question Lonnie.
Lonnie,  due to the amount of wattage that a water heater requires a dedicated circuit would need to be installed sized according to the specifications of the water heater manufacturer. This circuit will be either 120 or 240 volts. If there is an existing dedicated circuit with the correct size wire for the new water heater then the circuit can be converted either way by identifying the circuit wiring at both the electrical panel and the water heater location, color coding the wires appropriately and connecting the wiring to the required circuit breaker which is sized correctly to protect the wiring. Terminations to the circuit breaker and the neutral terminal will need to be adjusted for the specified required voltage configuration. Be aware that a 120 volt water heater is less energy efficient than a 240 volt water heater.

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2 Responses to “Electrical Circuit Considerations For Water Heaters”
  1. Piccolo James says:

    Dear Dave,
    Please advice and print a circuit for an Electrical Water Heater fully automatic, named
    ‘ BERLIN ‘ made by England. This electrical water heater was given by a renovation contractor of which all the wiring had been cut off. The base plate of the heater is 8kw 220v. AC only. The capacity of water volume is approx. 30 liters.
    Please sketch a circuit from main power supply to the Turntable nob, the +/- terminals, earthing and the pilot light. Thanking you very much in anticipation and help.

    Yours sincerely,


  2. Dave Rongey says:

    Hi Piccolo,
    The model number would be very helpful, and the label on the water heater should indicate the amperage and circuit requirements. In US calculations 8kw 220 volt would equate to a minimum 40 amp circuit, however in the UK this may be a little different so for best results please consult with a local electrician who will be able to convert the circuit into UK standards. Be sure to test the internal electrical components, especially the heating elements, because typically when electrical equipment is not functional it is common to cut the connection wires off short to disable wiring of the device.