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.
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.
Doug Miller (alphageek at milmac dot com)
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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