The adapter allows for easy measurement of alternating current and voltage on devices with a connected power plug. It is simply plugged in between the device and the socket. Individual currents of the phases L, the neutral conductor N, and leakage currents on the protective conductor PE can be measured contactlessly. The symmetrical load of the three phases can also be quickly and easily monitored. The insulated measurement bridges are suitable for most AC current clamps. Additionally, safety measurement sockets are available for direct measurement of individual conductors, such as for voltage measurements.