The non-contact voltage and magnetic field tester is used to detect alternating voltage at sockets and cables, as well as magnetic fields. The Voltcraft MS-520 can detect both. In addition to alternating voltage, the tester can also check the functionality of current-carrying coils, such as those found in relays and solenoid valves.

The tester is specified according to the highest safety class CAT IV 1000 V. It operates without contact, meaning that direct contact with the test object is not necessary. As a result, housings usually do not need to be opened.

When an electrical alternating field is detected, the test tip lights up red, and an audible signal is emitted. The built-in antenna in the tip responds only to the phase and not to the neutral conductor. When a magnetic field is detected, the test tip lights up yellow. In the case of simultaneous detection of electrical fields and magnetic fields, the yellow and red LEDs alternate in lighting up.

The MS-520 is designed to withstand rain and snow, or even a water jet, without malfunctioning. It can be used and stored in locations with high humidity, such as industrial sites, machine rooms, and not entirely dry garages, without any issues.

The housing and all control elements are constructed to be completely dustproof. Even after many years, the tester remains as functional as on the first day.

By pressing a button, a white LED lights up at the front, allowing the measurement point to be illuminated. This function also helps to find the way to the fuse box in dark rooms.