You can check if your box is grounded by using a volt meter . one side to the black wire and the other lead to the box, if you get 120v then the box is grounded.
thanks, but i ended up buying those little plug in things..... a lot safer, and then i don't even have to open it up --- too bad all the plugs are 2 prong......
i got the regular tester and the gfci tester
