A new dishwasher I removed an old dishwasher that was wired into a box in the wall. The box and the dishwasher only had a black and a white wire no ground. I was surprised by the lack of a ground all these years. Looks like the box was added on when the dishwasher was installed as a bx cable is running up to an outlet that is above the counter. The wall under the counter looks like it was patched when the wires were run. The new dishwasher had a 3 prong plug. So i wired a GFI outlet to the existing black and white wires and mounted it to a box I nailed to a stud Seems my dishwasher is not grounded. Will the GFI trip and prevent shock in this case? Or will my circuit breaker trip? FWIW My house was built in 1960 and had two prong oulets when we moved in. We had all the outlets replaced with 3 prong outlets 20 years ago I'm getting a sinking feeling that all these outlets are not grounded either.