Line tester reads power to 220V outlet when the breaker is off Related: Splitting a 220v line into a 110v line and a 220v line? Line-to-Line Voltage Reads 0V (or low, 15V at most) on Primary of Main Breaker (L-N both read ~120V) GFCI outlet trips overnight. The breaker indicates there is ground fault. Outlet tester shows no lights (no power?) Tester reads “HOT / GRD. REVERSE” Using a U.S. 220v water heater in a foreign country where the line voltage is already 220v