Electric Water Heater Not Measuring 240V

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Eddie G

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electric water heater not getting 240V. I have replaced both upper and lower thermostats and both elements. Three wires come from the wall into the water heater. Two are black and one is bare copper. Each black wire measures 120V when the other probe is on the metal ground. However, I do not measure 240v when one probe is on one black and the other probe is on the other black. See photos. Your help is immensely appreciated. Thank you so much !
twoWires 60929.jpg
Sticker Label 60929.jpg
 

Reach4

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I presume this WH used to work, and there has not been wiring work in the breaker box or at the WH since the WH stopped working..

What voltage do you read between the black wires? If near zero, I would have suspected the other ends of the wires were not wired to a 240 volt tandem breaker in the breaker box, but to two separate breakers. Yet the system used to work, so that cannot be it.

I guess I would next try temporarily powering a ~40 to 60 watt lamp between each black wire and the metal ground. If an open had developed on one of the wires, the disconnected wire could be capacitively coupled to the other. Your very high impedance voltmeter could see nearly full voltage.
 

Jadnashua

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If you can measure 120vac between each black/ground separately, but get essentially zero VAC between the two of them, unless there's an open somewhere and (as was said) you're getting some induced voltage (phantom), both leads are on the same side of the transformer, so that's why there's no voltage between them. It's like each of them are in parallel rather than being separate leads from separate sources.
 

Brent-o-be

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I have the same issue as described by Eddie G above. Was this problem ever resolved?
 
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