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 !