How should I wire my GFCI?
There are 5 wires from the box, two blacks, two whites and a copper wire. I used a multi-meter to test the blacks they both have voltage of 117v (-ish). One white has 30v (-ish) and the other white has none.
If I wire all of them to GFCI, two for Line and two for Load, its led turns green but it cannot be reset and there is no power from its socket.
If I only wire 1 set of black and white it works.
What should I do? Should I connect them to the same line port?
To fully power of this I have to switch the Disp and DW breaker off. (They are link together as the picture)