Professional voltage testing of electrical lines and installations in a handy pen format. The non-contact voltage tester ensures high work safety by detecting existing alternating current. The device determines the polarity of the L/N conductors, detects live wires even at greater depths, and locates electrical voltages in cables, sockets, lamp holders, and fuses. Line interruptions can be effectively identified. A highly visible LED indicator, pocket clip, and integrated flashlight ensure comfortable use. Non-contact detection of live wires. Locates electrical voltages in cables, sockets, lamp holders, and fuses. Simple determination of polarity on L/N conductors, for example, at sockets and terminal blocks. Effective identification of line interruptions in cables and wires.