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Thread: Wire size for 120V water heater?

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  1. #1
    DIY Member Artie's Avatar
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    Default Wire size for 120V water heater?

    I want to run this water heater, (10 gal., 120VAC, 1650W), at a remote location. (Approximately 20ft. from the breaker box.) Would 12-2 be sufficient?

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    Plumber jimbo's Avatar
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    1650 watts is about 13 amps. 12 guage wire is fine.

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    Homeowner Thatguy's Avatar
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    If you have an ohmmeter, before you install this heater check that the element resistance is at approx. (120v^2)/1650w = 8.7 ohms.
    It can't hurt to make sure.

    Their kwh rating for a year is based on it being on 17% of the time. I guess this is some consumer average usage.

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    DIY Member Artie's Avatar
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    Thanks guys.

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    Moderator & Master Plumber hj's Avatar
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    The KW for a heater is the "actual" wattage, not a "kw per year" statistic. The "kw/yr" number creates the "annual cost of operating the heater" which is a completely different thing.

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    Homeowner Thatguy's Avatar
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    Speaking of power usage,
    since the element runs on 120v, wiring an electromechanical analog clock across the element for 24 hours or so will tell the heat loss through his R8 insulation.
    If the clock advances 5 minutes every 600 minutes with no hot water being used then his loss is 1650w(5m/600m) = 14 w = 48 BTU/hr.

    I definitely have to find a day job. . .

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