Recently went to install a new hot water heater as the old one was leaking, old one was a small 110v unit but I opted to go to a large 240v unit to replace it. When I opened the wiring panel there are only a black and red wire, I was under the impression that 240v required 2 hot wires and a neutral. Is there something that I am missing or how differently do I wire this in. I have a 240v, 30amp breaker but don't know how to wire it with only a single hot and neutral wire.
Electric Hot Water Heater
Nov 21, 2006
3 Replies
If the unit is 4500 watts it will require a 30 amp circuit breaker, #10 cable of three wires: Two hot and a ground.. There is no neutral used
240V circuits use two hot wires and a *ground* (the bare wire), but no neutral. If the wire to your old 120V unit is 10-gauge or larger, you can use the same cable to connect the new 240V unit. In the breaker panel, connect the black wire to one pole of the 240V breaker, and the white wire to the other pole. At the water heater, connect black to black, and white to red. Mark the white wire at each end with black or red tape, paint, felt-tip marker, or whatever, to indicate that it's being used as a hot conductor.
A 240 volt circuit only has two hot wires. They are both 120 volts above ground. If you run the third wire (neutral wire) then either of the other 2 wires will be a hot wire and will be 120 volts between that neutral wire and either of the other two hot wires. YOu will also have a ground (usually bare wire) that goes to the fram of the water heater for safety.
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