This Socket Tester works for most European grounded sockets, but not for UK 3-hole sockets (for this, you'll need the country-specific grounding adapter).

With this socket tester, you can easily test whether your grounded socket is working and whether it is correctly connected to the ground via your home's ground loop or ground pin.

You can easily identify a grounded socket by the metal strips on the side (Dutch, European) or the metal pin that sticks out (Belgian, ...). If you do not see metal, your outlet is not grounded. Then, it makes no sense to use this tester.

Download the Test Chart for the Socket Tester